The go-to phaser builds for DIY'ers are:
Phase 45 – Intermediate build. 2 stages. FET matching required. No regen. Very subtle.
Phase 90 – Advanced build. 4 stages. FET matching required.
Ross Ropez – Advanced build. 4 stages. OTA design.
Small Stone – Advanced build. 4 stages. OTA design.
The design concept for "Causality 4" was to achieve a musically useful intermediate build 4 stage phaser with regen, using easily available parts, and requiring no matching of components. It has two swept stages using a dual OTA, and two fixed stages using opamps. The LFO utilises a dual opamp and is based on the MXR phasers, much simpler than the LFOs in either the Small Stone or Ross Ropez. The fixed stages came from an idea suggested by Mark Hammer in this thread: http://www.diystompboxes.com/smfforum/index.php?topic=80111.0 Having four stages, even if two are fixed, allows for the addition of regen, which for me is a phaser essential. The Regen control goes from zero to just short of self oscillation - some great sounds available here. The Depth control is particularly interesting and useful, specifying where in the spectrum the phasing occurs.
Your critiques are welcome!
Soundclips, perf and PCB layouts to follow - it's on the breadboard ATM, I want to build it first.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PhaserRev10.jpg)
great work! I wish you will post sample soon! It's so interesting to me, I love phaser...
Looking pretty cool. I'm keeping my eye on this thread...
Looks really good mate, I was looking at Mark's post the other day, fixed stages sounds very interesting. I'll be very interested to hear some sound samples.
Excellent. Thanks for putting the time into this, Rick. I think I just found my phaser.
Even before the first post I got it down and then this morning started designing up a PCB, my favourite part and it's really quite an elegant set of traces. With the opamps hanging off each end of the OTA it makes sense to have the quad opamp below the Ota and amps A and D as those on either end. It gets rather confusing for the VR feeds but a little complication always makes the PCB design process interesting. Thanks for the challenge Rick :icon_biggrin:
Looks interesting, can you please explain how the output mixer/amp is configured - gain etc?
Those 33nF capacitors attached directly between two outputs look bit weird to me ;)
Output buffer mixing 3.5*dry - 2.5*wet as well (there is maybe "typo", is not? That 47k resistor connected this way makes no sense there imo)
But you say it works, so.. :)
Please give us samples asap :) Thanks, T.
Quote from: sean k on November 24, 2009, 01:07:33 AM
Even before the first post I got it down and then this morning started designing up a PCB, my favourite part and it's really quite an elegant set of traces. With the opamps hanging off each end of the OTA it makes sense to have the quad opamp below the Ota and amps A and D as those on either end. It gets rather confusing for the VR feeds but a little complication always makes the PCB design process interesting. Thanks for the challenge Rick :icon_biggrin:
I'm starting to think that using two duals instead of the quad will make for a neater, more compact layout.
Quote from: StephenGiles on November 24, 2009, 06:26:17 AM
Looks interesting, can you please explain how the output mixer/amp is configured - gain etc?
Quote from: Thomeeque on November 24, 2009, 09:34:04 AM
Output buffer mixing 3.5*dry - 2.5*wet as well (there is maybe "typo", is not? That 47k resistor connected this way makes no sense there imo)
I screwed up on the schematic drawing the output stage, I've re-uploaded it now, refresh your browser to see the revision. Does that look better? I originally tried to output/mixing stage of the Ross, but I was getting slightly less than unity, so I reconfigured it to what it is now, which gives unity at the output. Sorry for the error guys, :icon_redface:
Quote from: Thomeeque on November 24, 2009, 09:34:04 AM
Those 33nF capacitors attached directly between two outputs look bit weird to me ;)
This design takes a little from the Ross, a little from the Phase 90, and a little from me. The two OTA stages are identical to those in the Ross though: http://www.tonepad.com/getFile.asp?id=99
I've also added a 10K resistor between lug 1 of the Depth pot and ground, as I found weird things were happening with the pot fully grounded. It doesn't do much to limit the range, but sorts out the issue.
Quote from: frequencycentral on November 24, 2009, 12:42:40 PM
Quote from: Thomeeque on November 24, 2009, 09:34:04 AM
Those 33nF capacitors attached directly between two outputs look bit weird to me ;)
This design takes a little from the Ross, a little from the Phase 90, and a little from me. The two OTA stages are identical to those in the Ross though: http://www.tonepad.com/getFile.asp?id=99
Oh, I see! :icon_redface:
Quote from: Thomeeque on November 24, 2009, 01:24:19 PM
Oh, I see! :icon_redface:
Don't be bashful! And thanks to you and Stephen for alerting me to the error in my drawing of the output stage.
Ah, that makes more sense now, many thanks. For a fatter sound, perhaps a second phasing network in parallel with the first but using different capacitors.
Quote from: frequencycentral on November 24, 2009, 01:29:59 PM
Quote from: Thomeeque on November 24, 2009, 01:24:19 PM
Oh, I see! :icon_redface:
Don't be bashful! And thanks to you and Stephen for alerting me to the error in my drawing of the output stage.
To be honest, I've made one error in that second statement either :icon_mrgreen: - dry signal ratio would be different (I've forgot to calculate-in influence of that 47k resistor) ;)
T.
....................and sorry Scruffie (http://www.diystompboxes.com/smfforum/index.php?action=profile;u=19060) I won't be doing a vero layout! :icon_mrgreen:
Ah yes, you finished your sooner than me. And it probably sounds better. ;D :icon_redface: >:( ;D
Backgound:
http://circuitworkshop.com/forum/index.php?topic=174.0
My dual OTAs are in and I'll start working on OTA version over the long holiday weekend.
Quote from: culturejam on November 24, 2009, 02:16:27 PM
Ah yes, you finished your sooner than me. And it probably sounds better. ;D :icon_redface: >:( ;D
Ah yes CJ, but if you hadn't asked this question (http://circuitworkshop.com/forum/index.php?topic=173.0) around the same time as Mark Hammer posted this thread (http://www.diystompboxes.com/smfforum/index.php?topic=80111.0) I never would have done this design. So props to you both. :icon_biggrin:
Quote from: frequencycentral on November 24, 2009, 02:03:26 PM
....................and sorry Scruffie (http://www.diystompboxes.com/smfforum/index.php?action=profile;u=19060) I won't be doing a vero layout! :icon_mrgreen:
:D I actually thought about asking... but I thought seeing as how much you love it you'd be doing it anyway.
Looks great, Rick. I can barely find the time to build a booster, I don't know how you manage to be so productive.
Quote from: Ben N on November 24, 2009, 03:49:18 PM
Looks great, Rick. I can barely find the time to build a booster, I don't know how you manage to be so productive.
Well, y'know, at the expense of everything else, life, work, relationships, family............... :icon_rolleyes:
Anyway, here's a soundclip for ya: http://dl.dropbox.com/u/967492/Causality%204%20Phaser.mp3
Signal Path:
My below average guitar fumblings >>> Squier Tele Custom (bridge humbucker) >>> Big Muff Violet Rams Head (clone) >>> Causality 4 (on the breadboard) >>> Harley Benton GA5 (VJ clone) >>> Shure SM58 >>> Wavelab.
No other processing. A montage of different settings, a bit of extreme knob twiddling going on too.
.....and here's a clean clip: http://dl.dropbox.com/u/967492/Causality%20Clean.mp3
Signal Path:
My below average guitar fumblings >>> Squier Tele Custom (bridge humbucker) >>> Magnus Modulus (a bit of chorus and delay) >>> Causality 4 (on the breadboard) >>> Harley Benton GA5 (VJ clone) >>> Shure SM58 >>> Wavelab.
I listened to the first set of clips you posted .
I liked the first riff the 3rd time you played it as having the sound I liked best.
SO what sub minis does this pedal use again? :icon_lol:
Those little black low profile ones that you can get nowadays...... :D
Rick, those sound great!
Finally listened to the clips. Very impressive. One of the things that I was sure I had heard on my 4-swept/2-fixed Ropez was that the effect got more intense as it swept upwards, and the same seems to be even more true with 2-swept/2-fixed in this instance. Very musical sounding. Thanks.
Dang you, Rick. Just when I think I am caught up with builds, you go and do something like this and make me put another project on the to-build list. The wife doesn't like you much, I don't think. That's okay, she doesn't know it's your fault.
Quote from: Mark Hammer on November 26, 2009, 10:43:24 AM
Finally listened to the clips. Very impressive. Very musical sounding. Thanks.
Wow, praise indeed from from high priest of DIY phasers, thanks Mark!
Quote from: Ripthorn on November 26, 2009, 11:21:15 AM
Dang you, Rick. The wife doesn't like you much, I don't think.
:icon_mrgreen:
I'm working though the perf/PCB layouts at the moment. Not sure yet if it will end up using a quad opamp or if I'll go for all duals. I was aiming to get it on a 20 x 20 pice of perf, but the more I think about it the more I think I should spread it out a bit, as the concept is for an intermediate, easy build phaser, so I might try 20 x 25 which is the same size as the Tonepad Ropez. What do you guys think?
Oh, and
cathexis - do you fancy doing a vero layout for this?
20x25 is still a reasonably small piece of board, so I would be fine with that. This is going to be fun.
Could we have one layout for your normal users, and one for us perfboard masochists :icon_biggrin:. For some inexplicable reason I get a kick out of building the tiniest layouts I can find, it takes longer, it's incredibly fiddly, you can't just use any old parts and there is normally no real advantages.... but I like it :icon_lol:
Can we get it in an Eddystone 111x60x27 ?
Well it looks like it's going to be 20x22, which will easily fit in an Eddystone 111x60x27, that's the size enclosure I plan on using anyway. I'm a perfboard masochist myself, but I'll only be doing the one size layout (sorry Aston), it could be smaller but I want to make it an accessible and easy build for less experienced DIY'ers. If this project becomes popular I'm sure we could persuade John Lyons to do a run of PCBs.
Fair enough :icon_biggrin:, a bit cheeky to hope for a separate layout just for me! Its just that I'm getting glasses for the first time in my life next week, so I'm looking forward to being able to see what I'm soldering and consequently build even smaller thingamajigs.
Thanks for this build Rick, it's on the list and I've got free time coming up *rubs hands together*
Quote from: frequencycentral on November 26, 2009, 05:13:43 PMI'm a perfboard masochist myself...
Pain is good. Embrace the pain.
Here's the perf layout, as yet unverified, I'll go over it with a fine toothcomb and build it this weekend. Anyone wanna check for errors with me? The only variance from the schematic is that I've used the two OTA's of the LM13700 in the opposite order, which just made the layout easier. I've also included a LED resistor (R33) with a nominal value of 1k.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PerfLayout.gif)
..............and here's a reveal view of the same layout:
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PerfReveal.gif)
I'd be happy to look through the schematic/perf, but the safest way for me to check it is to build it, unfortunately even after 3 mammoth orders recently I'm still missing two of the IC's. :icon_confused:
I'll run through it, perhaps fresh eyes will catch something.
Too much dry signal for me in them clipz...
I`d replace that 10k going to the 1st stage (drawn above that input-1k) with a link...
(or should I say: Carbon-comp 39 Ohm in parallel with a bifilar wire-wound non-inductive 5.6 Ohm :icon_razz: )
and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip (:icon_wink: :icon_wink: :icon_wink:) , while turning up the "Regen"...
Quote from: Skruffyhound on November 27, 2009, 03:47:51 PM
I'll run through it, perhaps fresh eyes will catch something.
Thanks, I've already spotted a missing jumper between u16 and u17. I'm going to update the layout when I'm sure I've thouroughly debugged it.
Quote from: puretube on November 27, 2009, 04:21:57 PM
Too much dry signal for me in them clipz...
I`d replace that 10k going to the 1st stage (drawn above that input-1k) with a link...
Thanks Ton, I'll try that.
Quote from: puretube on November 27, 2009, 04:21:57 PM
and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip (:icon_wink: :icon_wink: :icon_wink:) , while turning up the "Regen"...
Police siren?? :icon_wink:
Quote from: frequencycentral on November 27, 2009, 04:40:59 PM
Quote from: puretube on November 27, 2009, 04:21:57 PM
and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip (:icon_wink: :icon_wink: :icon_wink:) , while turning up the "Regen"...
Police siren?? :icon_wink:
Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...
On another try, I`d feedback
from the last stage...
or even try to feedback
to an earlier stage (tweak, tweak...)
Quote from: frequencycentral on November 24, 2009, 12:42:40 PM
I've also added a 10K resistor between lug 1 of the Depth pot and ground, as I found weird things were happening with the pot fully grounded. It doesn't do much to limit the range, but sorts out the issue.
Kinda reminds me of a similar issue (last year ?) in an other OTA-project,
where the CV needed to get over the "diode-drop-hump" to become effectively turned into a proper I
ABC :icon_wink:
Quote from: puretube on November 27, 2009, 04:59:17 PM
Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...
Ah, a vibe switch. I misunderstood, I read as replace with a link. :icon_redface:
Quote from: puretube on November 27, 2009, 04:59:17 PM
On another try, I`d feedback from the last stage...
I'll try that - but should it make any difference? Please explain.... :icon_eek:
Quote from: puretube on November 27, 2009, 04:59:17 PM
or even try to feedback to an earlier stage (tweak, tweak...)
But it has to be an odd number of stages right?
Quote from: frequencycentral on November 27, 2009, 05:33:42 PM
But it has to be an odd number of stages right?
Who says: "ODD" anymore, when such a circuit is
shifting its phase-relations from at least zero° to almost or even over 360°
for almost any frequency ??? :icon_mrgreen:
Quote from: frequencycentral on November 27, 2009, 05:33:42 PM
Quote from: puretube on November 27, 2009, 04:59:17 PM
Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...
Ah, a vibe switch. I misunderstood, I read as replace with a link. :icon_redface:
No: it`s not a so-called: "Vibe-switch", but rather a: "Wet-Only-switch"... :icon_razz:
You know about where I am with this stuff so this is by no means guaranteed correct, but I downloaded the datasheets and checked all the pins, cross referenced the layout with the schematic, writing in the resistor and cap numbers from the layout to the schem and crossing them off on the component list. I didn't find any mistakes. I didn't catch the missing jumper though :icon_eek:
Quote from: Skruffyhound on November 27, 2009, 06:34:08 PM
You know about where I am with this stuff so this is by no means guaranteed correct, but I downloaded the datasheets and checked all the pins, cross referenced the layout with the schematic, writing in the resistor and cap numbers from the layout to the schem and crossing them off on the component list. I didn't find any mistakes. I didn't catch the missing jumper though :icon_eek:
Thanks Aston, great to have another set of eyes on it. I've just completed the PCB layout, with red traces for +ve, brown for ground and orange for vref - much easier to check the connections. BTW, the missing jumper is under C1, I'll re-upload the perf layout over the weekend.
Oh I saw the jumper after you mentioned it (u16 to u17) and of course you were right, I just didn't catch it on my own :icon_rolleyes:
I've had a bunch of CA3080's collecting dust for the past 3 or 4 years. I'll have to try this out so I can put them to good use.
I would save the 3080's for projects that specifically call for them. The LM13700 is biased differently than other OTA's and so you wouldn't be able to just stick them in a circuit anyways, there would be a bit of redesign to do first. The 13700 is a solid chip though, I've used it quite extensively with a lot of luck (it has its limitations though, i.e. it can't deal with currents above about 500uA).
Quote from: Cliff Schecht on November 28, 2009, 03:14:21 AM
I would save the 3080's for projects that specifically call for them. The LM13700 is biased differently than other OTA's and so you wouldn't be able to just stick them in a circuit anyways, there would be a bit of redesign to do first. The 13700 is a solid chip though, I've used it quite extensively with a lot of luck (it has its limitations though, i.e. it can't deal with currents above about 500uA).
I don't think there would be too much to it to drop a couple 3080's in that circuit but since the breadboard rig is tied up right now I do have time to make an order so I may try the 13700. Never used them. Are they still readily available? I'd love to find some CA3280's somewhere (a better quality dual OTA).
BTW, Hello to all. I've been absent from here/electronics for 3 years or so. I missed everyone and everything here.
Quote from: puretube on November 27, 2009, 04:21:57 PM
Too much dry signal for me in them clipz...
I`d replace that 10k going to the 1st stage (drawn above that input-1k) with a link...
I've taken Ton's advice (of course) and removed that 10k resistor. Now the wet is louder relative to the dry. Also the whole circuit got louder, so I've replaced the output buffer's 47k to vref with 100k to vref to compensate. I'll alter the schematic and layouts to reflect this, and re-upload them to replace the existing (as I don't want to bog this thread down with lots of updated schematic/layouts)
The option is also there for people to add a wet/dry mix pot, or a wet only switch as Ton suggests. But I want to keep it simple right now, so just three knobs, though I will include a couple of pads on the PCB for a wet only switch which can be jumpered if not required.
Quote from: ragtime8922 on November 28, 2009, 10:19:06 AM
I don't think there would be too much to it to drop a couple 3080's in that circuit but since the breadboard rig is tied up right now I do have time to make an order so I may try the 13700. Never used them. Are they still readily available?
LM13700 are easily available. I'm assuming this circuit should also work with LM13600 and NE5517, though I haven't got any of either to try. To build this circuit with 3080's you'd have to add a couple of transistor after each 3080 configured as a darlington pair to replicate the 13700's built-in buffers. I've got a bunch of (extreme mojo) metal can 3094's and 3080's myself, but I'm saving them for another project
I've corrected the perf layout (and reveal) on page 2, so they reflect the Rev 1.2 schematic now on page 1.
Here's the PCB layout and it's Pnp, It's a bit different to the perf layout in that I've tried to lie the resistors flat wherever possible, though I guess you could build a perf layout from the PCB layout - much easier to follow actually, with the colour coding of +ve, ground and vref.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PnP.gif)
Sounds quite nice, I particularly like the length and shape of the LFO sweep. I suspect that you could do with refining the mix between the clean and the phased signal. It sounds as if it's not quite as deep as it could be, slightly more vibrato than phasing.
Quote from: Jaicen_solo on November 28, 2009, 06:12:20 PM
Sounds quite nice, I particularly like the length and shape of the LFO sweep. I suspect that you could do with refining the mix between the clean and the phased signal. It sounds as if it's not quite as deep as it could be, slightly more vibrato than phasing.
Quote from: frequencycentral on November 28, 2009, 10:57:29 AM
I've taken Ton's advice (of course) and removed that 10k resistor. Now the wet is louder relative to the dry.
Yeah sorry about that, the two extra pages weren't showing up on my PC for some reason!
Hi,
built it today, but with no success. Though I have to say, that I redraw your layout in sprint layout as I don't like diy lc layouts and all that scaling trouble that comes with it. I'll double check this afternoon but at the moment I have no hope, that it will be successfull.
Cheers
Helge
Edit: I attached my layout. Sorry, no component values at the moment, but as it is similar to yours it should be clear.
(http://i62.photobucket.com/albums/h92/hellge/Causality4.jpg)
Hi Helge, quick work! But sorry you're having trouble. The layout is not verified yet though. I think it's correct, but I need to build it to confirm it's correct. What are the symptoms of your units non-functionality?
Quote from: frequencycentral on November 29, 2009, 03:19:59 PM
Hi Helge, quick work! But sorry you're having trouble. The layout is not verified yet though. I think it's correct, but I need to build it to confirm it's correct. What are the symptoms of your units non-functionality?
Hi,
yeah, I'm sorry. I have to admit that my malfunction description wasn't that detailed.:D First to name the things that I think do work: The LFO works and the phase stages around the OTA (only a guess). So my suspicion is that something around the fixed phase stages and the mix stage of the Tl074/84 doesn't work. I only can hear some phasing sounds with the depth and speed pot up while R13 is unconnected. With R13 connected the phasing sound is barely noticable also on lower speed settings the effect seems to dissappear. I knew that the layout was still unverified, but to me it looked correct too. What a pitty!:D
Cheers
Helge
Quote from: Fuzz Aldryn on November 30, 2009, 04:20:14 AM
Quote from: frequencycentral on November 29, 2009, 03:19:59 PM
Hi Helge, quick work! But sorry you're having trouble. The layout is not verified yet though. I think it's correct, but I need to build it to confirm it's correct. What are the symptoms of your units non-functionality?
Hi,
yeah, I'm sorry. I have to admit that my malfunction description wasn't that detailed.:D First to name the things that I think do work: The LFO works and the phase stages around the OTA (only a guess). So my suspicion is that something around the fixed phase stages and the mix stage of the Tl074/84 doesn't work. I only can hear some phasing sounds with the depth and speed pot up while R13 is unconnected. With R13 connected the phasing sound is barely noticable also on lower speed settings the effect seems to dissappear. I knew that the layout was still unverified, but to me it looked correct too. What a pitty!:D
Cheers
Helge
Helge, I've spotted an error in your layout. There is a missing trace under R26. If you look on my layout and PnP you'll see there is an orange trace to vref that is under R26. Probably easier to see on the PnP than on the layout itself. Which means that the second OTA stage, the final fixed stage and the output buffer on your build are not receiving a vef. Hope that helps.
Hi Rick,
thanlks for your help. I did fix that little mistake and now I have somewhat of phasing. But now new strange bugs appeared. I guess this phaser is not supposed to be an envelopephaser, that stucks in the low sweep if you hit youir strings harder? Mine does that atm. Also it tends to distort (I'm using Mini HB with about 8kOhm) and the regeneration pot is pretty... hm, touchy, not to say useless? I gues I still have something made wrong here.... :icon_lol: After building about 25 FXs without debugging the last year I guess now it's time to have some bad luck.:D
Cheers
Helge
I just drew up my layout again, referencing the schematic and my original layout. A very intensive part by part examination. It came out the same. I can't find any issues with it, so I'm just gonna build it.
@ Helge: Your envelopephaser thing sounds very weird. I used a humbucker for my soundclips, I'm not getting any distortion. Did you use any part substitutions in your build? I did a few experiments on my breadboarded prototype tonight, the only way I could get it to @#$% up was to replace the TL084 with a LM324.
Just finished building this onto perf. It worked first time, sounds exactly the same as the one on the breadboard. I still have a little fine tuning to do, Helge is right about the regen being touchy, maybe it need to be 10k or 22k. I also need to up the value of the resistor to ground from the depth pot. I perf'ed mine referencing the PCB layout, which is very close to the perf layout but neater and easier to follow.
Here's a couple of photos of my verified build:
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0001-5.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0002-3.jpg)
I did experience some strange behaviour though when I first turned it on (with the Depth control at minimum), which could have passed for the 'envelopephaser' effect that Helge mentioned. It turns out that the Iabc inputs of LM13700 don't like to be so close to ground (actually two diode drops above) , and phasing didn't start for me straight away. I played around on the breadboard and replaced R8, 10k on my PCB layout, with a 47k. Now that problem is solved.
I also used a 47k Log for the Regen control instead of 47k Lin, which makes sense as it's actually audio that the pot is dealing with. The most usable resonance sounds are higher up, but I'm still finding I want the whole range of the pot rather than using a lower value pot.
Finally, the regen on my build is a little further from self oscillation than on my breadboarded version, so I'm going to experiment with maybe dropping the value of R24 to 8k2.
I will update the schematics and layouts with these changes ASAP.
Hey Rick,
I've been watching this thread. I'm curious how this one compares sound-wise with your Phase Revolution? I've been playing the heck out of that guy pretty much every day, and I love it, especially in the box with a Magnus Modulus. Does this phaser bring something new to the table in your opinion?
Thanks!
Quote from: doc_drop on December 04, 2009, 01:55:46 PM
Hey Rick,
I've been watching this thread. I'm curious how this one compares sound-wise with your Phase Revolution? I've been playing the heck out of that guy pretty much every day, and I love it, especially in the box with a Magnus Modulus. Does this phaser bring something new to the table in your opinion?
Thanks!
Hi Chris,
The concept with this project was for a phaser that anyone could build with no matching of components. Do a search for builders who have issues around FET matching in Phase 45, Phase 90 and Phase 180 builds and you'll see what I mean.
This is my third phaser build. My first was the Phase 45 with Maillet mods (http://www.diystompboxes.com/smfforum/index.php?topic=76657.0) a.k.a. Phase Evolution, I was so disappointed in the (lack of) phasing that I added two extra phase stages, which makes it a nice phaser, somewhat akin to the Phase 90. My second was the Phase 180 Plus (http://www.diystompboxes.com/smfforum/index.php?topic=76762.0) a.k.a Phase Revolution, it's taken some tinkering to get it near to what I want, and I'm still not entirely satisfied with it. Causality 4 has some great sounds, more flexible IMO than my Phase Evolution, easier to use than my Phase Revolution - as you'll know there are a number of settings on the Phase 180 which just do nothing.
So, all in all, Causality 4 is not trying to compete with a Phase 180. It has a sound of it's own, there are no settings that 'do nothing', and the Depth control works particularly well and gives a broad palette of tones. I'd say it's probably 'more' than a Phase 45 or Phase 90, and an easier build than either of them. For it's sound, simplicity and utility, Causality is my favourite of my three phasers right now - but I do have the PCB's to build an 8 stage Ross Ropez, to which I'll add 8 extra fixed stages making 16 in all, I'll have each set of four stages switchable, and it's going to have every concievable mod................
My brain waves are getting a little "phasey" trying to keep the names all straight! ;D
But, it sounds like this one might be a fun build to do, one way or the other. I'll let you sort out the details, and put this on the to do list. (I'll have to wait see what your 16 stage phaser winds up looking like...)
It is true that there are settings that don't phase on my Phase Revolution. But what I love about it is that you can get everything in between nothing and wide crazy resonant phasing. By the way, I have found that running something that buffers the signal in front of it helps with the sound. I especially like a valvecaster in front. It can easily overload with a hot signal, so keeping the signal tamed really helps pushing it to the edge of madness and not having hiss n' stuff.
Thanks as always for the in depth response!
Quote from: frequencycentral on December 04, 2009, 01:09:48 PM
Finally, the regen on my build is a little further from self oscillation than on my breadboarded version, so I'm going to experiment with maybe dropping the value of R24 to 8k2.
Whoa! 8k2 makes it into a
SIREN! I think I'll stick with 10k. :icon_biggrin:
Hey Rick , what are the dimensions for the PCB layout?
Thanks,Carlos
Quote from: invalidcd on December 05, 2009, 11:00:42 AM
Hey Rick , what are the dimensions for the PCB layout?
Thanks,Carlos
My perfboard is 50mm x 56mm approx. The PCB layout should be the same size.
Well I doubt it would be as small as whats already done but I just gotta do things my way.
(http://i4.photobucket.com/albums/y115/quickkiwi/effects/causality4.jpg)
Your layout has it's own unique beauty Sean, as always. Did you catch these couple of important updates?
Quote from: frequencycentral on December 04, 2009, 01:09:48 PM
I did experience some strange behaviour though when I first turned it on (with the Depth control at minimum), which could have passed for the 'envelopephaser' effect that Helge mentioned. It turns out that the Iabc inputs of LM13700 don't like to be so close to ground (actually two diode drops above) , and phasing didn't start for me straight away. I played around on the breadboard and replaced R8, 10k on my PCB layout, with a 47k. Now that problem is solved.
I also used a 47k Log for the Regen control instead of 47k Lin, which makes sense as it's actually audio that the pot is dealing with.
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0004-10.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0009-7.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0006-9.jpg)
Nope, I didn't Rick but it easy enough to change those things as I haven't bought parts or even started the etching so its all good. I'm looking forward to this one actually. In the future, theres going to be a museum devoted to your stuff...well a section anyways in the great little DIY analog FX museum... thy will catch on! :icon_biggrin:
Quote from: sean k on December 06, 2009, 10:33:55 PM
Nope, I didn't Rick but it easy enough to change those things as I haven't bought parts or even started the etching so its all good. I'm looking forward to this one actually. In the future, theres going to be a museum devoted to your stuff...well a section anyways in the great little DIY analog FX museum... thy will catch on! :icon_biggrin:
Definitely--I can see it now: "The 21st century guitar effect designer: A picture of complete and hopeless insanity"
:icon_cool:
Rick - any idea where to tap an LED for a "speed" indicator ?
Thanks !
Dan
Hi all,
Quick intro to get out the way first. Been a lurker for ages, learnt loads while i've been here. I'm sure i'll post an official hello at some point but for now........
Anyone working on a vero layout for this?
I'm about half way through one and hope to post it for all at some point over the weekend, (if my wife and daughter allow me!)
Probably won't get to build it till next week so a few eyes glancing over it would be great.
Quote from: danielzink on December 17, 2009, 08:46:06 PM
Rick - any idea where to tap an LED for a "speed" indicator ?
Thanks !
Dan
If you look at the LFO on the schematic, it's made up of two opamps. It's basically a Phase 90 LFO with a unity gain buffer tacked on. I would think tapping off the output (via a suitable resistor) of either of the opamps would do the job. I'd try the second opamp, so tap off from lug 3 of the Depth pot. Personally I avoid speed indicator LED's as the current drawn by the LED as it switches on can cause ticking.
Quote from: sundgist on December 18, 2009, 10:39:46 AM
Hi all,
Quick intro to get out the way first. Been a lurker for ages, learnt loads while i've been here. I'm sure i'll post an official hello at some point but for now........
Anyone working on a vero layout for this?
I'm about half way through one and hope to post it for all at some point over the weekend, (if my wife and daughter allow me!)
Probably won't get to build it till next week so a few eyes glancing over it would be great.
Uh, I have a real problem deciphering vero layouts. :icon_redface: But I'll give it a shot if you want to post yours.
cathexis is the vero expert around these parts though.
Have checked this out as much as I was able to last night, should hopefully be ok, but had to keep breaking off to do home and family stuff so possibly some mistakes have crept in.
My parts references are a bit random to say the least and with the many similar resistor values makes following this layout a bit of a PITA. Should have followed the numbering of the existing layouts.
For some reason DIYLayout didn't show the complete parts list so i've left this off and typed them out below.
If anyone feels courageous enough to have a look over it and notices any mistakes let me know and I'll update. But I don't envy the task. I'll do another check before I start building tomorrow.
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard.gif)
Watch for jumpers and trace cuts under the IC's and trace cuts under R25, R16, C4.
No track cut between pins 1 and 16 of IC1.
R1: 220K
R2: 220K
R3: 1K
R4: 470K
R5: 27K
R6: 27K
R7: 6.8K
R8: 100K
R9: 100K
R10: 10K
R11: 10K
R12: 10K
R13: 10K
R14: 10K
R15: 10K
R16: 10K
R17: 1.8K
R18: 27K
R19: 10K
R20: 27K
R21: 1.8K
R22: 27K
R23: 27K
R24: 10K
R25: 4.7K
R26: 220K
R27: 220K
R28: 220K
R29: 47K
R30: 220K
R31: 10K
C1: 10uF
C2: 10uF
C3: .1uF
C4: .1uF
C5: .0047uF
C6: .047uF
C7: .033uF
C8: .033uF
C9: .01uF
C10: 10uF
IC1: lm13700
IC2: tl084
IC3: ne5532
Quick edit on the above to add wet only switch.
Refresh browser.
Awesome! This looks great, thanks for the layout. ;D
This is definitely going into my BUILD NOW FOR THE LOVE OF GOD pile. Question, is it possible to somehow make a wet only output in tandem with the regular output?
Re-checked my vero layout. Have updated so refresh browser if you don't see v1.1
Found a resistor in the wrong position (10k at bottom right of board).
Have re-labelled all parts with their values (makes it easier to follow), all caps are in uF.
Should be fine to build, I was hoping to start today but don't think I'll get a chance. Unless anyone else has a go I should be able to verify the layout next weekend.
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard.gif)
Quote from: deathfaces on December 19, 2009, 10:03:58 PM
Question, is it possible to somehow make a wet only output in tandem with the regular output?
I would imagine you would need to tap off from the output of the final fixed phase stage opamp (top right of the schematic) and feed it into a duplicate of the output buffer stage. Not 100% sure that this would work but worth a try.
@ sundgist: I'll try to look your layout over by next weekend.
A guy on another forum asked about adding extra swept stages. "Causality 6", unverified.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality6PhaserRev10.jpg)
Quote from: frequencycentral on December 20, 2009, 03:58:09 PM
A guy on another forum asked about adding extra swept stages. "Causality 6", unverified.
Sexy just got sexier!
......or there's always the option of sandwiching this (http://www.tonepad.com/getFile.asp?id=100) in between the two swept stages of Causality 4
Quote from: frequencycentral on December 20, 2009, 03:58:09 PM
A guy on another forum asked about adding extra swept stages. "Causality 6", unverified.
Now I'm really looking forward to getting this built.
I reckon I can get extra stages added on a seperate board with just a trace cut and some wiring to my vero.
Cut trace at i11 and insert the extra stages between the 13700's two opamps, then just supply the new board with 9V, Vref, GND and Depth from a1.
Switch to select no. of stages might be on the cards...!
I'll draw this up and post once i build what i've got so far.
"I'm gonna need a bigger box"
Important Update:
I've been experimenting to get a wider LFO sweep. I played around with the LFO on the breadboard and found that if I replace R5 with a 47k resistor (was previously 220K) I get a broader LFO sweep, which is very pleasing.
For anyone who has already built this and wants to apply the 'wider LFO sweep mod' without removing R5 from the board, just parallel it with a 68k resistor, which will give you 51k.
The mod also has the effect of slowing down the LFO, so the fastest speed is slower, but so is the slowest speed.
It also has the effect of making the LFO sweep slightly asymetrical. Subbing a 68K for R5 gives a deeper sweep ,though not as deep as a 47K, but the symetry is better. If you want to do this without removing R5, parallel it with a 100K.
I think I would just stick a little switch in there to choose between the two. Now I'm just waiting for you to do this with submini tubes... :icon_lol:
So where do you find the IC's? I just checked at Small Bear's site, but couldn't find the LM13700 or the TL084. Perhaps Mouser or such, but I'm trying to find them and since I've only ordered from Smallbear and PPP I'm not sure how to track those parts done.
jacob
Mouser or Digikey should carry those. The LM13700 is (if I remember right) a dual or quad OTA and the TL084 is a type of quad opamp. They are just not your typical TL072 or similar that Small Bear carries.
13600/-700 are dual: http://www.smallbearelec.com/Detail.bok?no=224 http://www.smallbearelec.com/Detail.bok?no=789
I just built the C4 on vero. When the pedal is turned on i am getting a significant drop in volume. Also the regen knob does not seem to work at all. Has anyone built this on vero and got it to work? I know its not verified.
Quote from: mafew129 on January 12, 2010, 10:39:24 PM
I just built the C4 on vero. When the pedal is turned on i am getting a significant drop in volume. Also the regen knob does not seem to work at all. Has anyone built this on vero and got it to work? I know its not verified.
I haven't fully checked that stripboard layout - I actually avoid stripboard like the plague and have a real problem 'reading' stripboard layouts. But:
- The 6k8 resistor between r13 and s13 should be 68k, that will explain the volume drop.
- On reflection, the regen pot should probably be a lower value than 47k, probably 10k or 22k would do. Try maxing it out - it should start to howl, if it doesn't there must be some other issue either with your build or with that layout. The 10k resistor between n2 and n4 stops the device from self oscillating, you could try a lower value there, but I found that even dropping it to 8k2 caused self oscillation with the regan pot maxed.
Did you use LM13700 and TL084 as specified? A guy over at FSB tried various different (LM324, TL072 and LM13600) IC's and had some issues, but found it worked fine with the specified IC's.
Finally, re the value of R5 on the PCB layout (that's the 220k on the stripboard layout between v12 and x12). I ended up adding a switch to my build to toggle between 220k and 100k.
Rick
Quote from: frequencycentral on January 13, 2010, 11:46:59 AM
Quote from: mafew129 on January 12, 2010, 10:39:24 PM
I just built the C4 on vero. When the pedal is turned on i am getting a significant drop in volume. Also the regen knob does not seem to work at all. Has anyone built this on vero and got it to work? I know its not verified.
- The 6k8 resistor between r13 and s13 should be 68k, that will explain the volume drop.
Cheers for pointing that one out. Not sure how I misread that. Have updated the layout (refresh browser).
Am getting some time in building it at the moment.
Kinda just got stuck into this and found it hard to stop.
:icon_biggrin: I can now verify the vero layout as working. :icon_biggrin:
No changes other than correcting the 6k8 resistor to 68k.
Made a few subs as I had a few parts missing.
22uF used instead of 10uF for the two electros filtering V+ and Vref.
10k log used for Regen, gets quite resonant and peaky enough at max.
100k lin used for Depth with 100k resistor in parallel. Seems to taper nicely enough (before I put the resistor in, the LFO seemed stop LFO'ing from time to time when adjusting the depth?). I'm thinking of doing similar with the Speed pot, just to spread out the higher speeds a bit.
IC's used, lm13700, TL074, TL072
Plan on switching 220k R5 between two values.
I left a few extra rows on the bottom of my board, plus theres that empty space on the bottom left. Might just fit a Mill bypass in there.
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality-4-Built.jpg)
Managed to have a short play with it with a clean guitar tone. I'm very pleased, having only ever used phasers on digital multieffects. This is quiet, clean sounding and usable. Will give it a good listen tomorrow with some dirt pedals when I can turn the volume up.
Next on the cards is an addon board with some extra switchable stages (will post layout here) and probably a few tweaks here and there as I get to know it a bit better.
Thanks for a really nice first analog phaser.
Quote from: sundgist on January 13, 2010, 09:43:05 PM
Kinda just got stuck into this and found it hard to stop.
:icon_biggrin: I can now verify the vero layout as working. :icon_biggrin:
No changes other than correcting the 6k8 resistor to 68k.
Awesome! You just made my day. I can finally replace that crappy plastic cheapo phaser on my board! Thanks for the circuit Rick!
I just got a PCB I ordered from John Lyons before I saw the Vero and was wondering about the LED on the bottom right. Can I skip it and use a regular 3PDT bypass LED scheme? Board mounted LEDs always mess me up for some reason...
Quote from: svstee on January 18, 2010, 01:45:43 PM
I just got a PCB I ordered from John Lyons before I saw the Vero and was wondering about the LED on the bottom right. Can I skip it and use a regular 3PDT bypass LED scheme? Board mounted LEDs always mess me up for some reason...
You can skip it, but all it is is the LED's resistor mounted on the board conveniently close to ground, so ideal for regular 3pdt bypass schemes.
OK, I see it now. Thanks!
Built it and loved the way it sounded. My only complaint was that the Depth pot was working backwards, so I switched lugs 1 and 3. Fixed it and everything worked great for about 5 minutes, but then it started to produce this nasty, harsh, gated clipping whenever I played hard. Still sounds nice when I play with a real light touch, but crappy when I really lay into it. Happens regardless of there the pots are. Only changes are that I made r5 switchable between 47k and 220k, and I used the "Wet" switch.
Anyone else have this problem? Did I mess something up when I switched the Depth lugs around? They were where the layout said they should be when the pot worked backward (more depth when pot was turned left, CCW).
Thanks!
Hadn't played with the wet only switch until now. Noticed I had put it in the wrong place and was removing the wet part of the sound rather than the dry. :icon_redface:
I have corrected the layout (now v1.3 refresh browser) but if you have already built it using v1.2 here is v1.2a showing the corrections.
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard%20Corrected.gif)
My apologies. :icon_redface:
P.s. or maybe leave it as is if Dry Only is your thing.
Quote from: svstee on January 18, 2010, 07:17:30 PM
Built it and loved the way it sounded. My only complaint was that the Depth pot was working backwards, so I switched lugs 1 and 3. Fixed it and everything worked great for about 5 minutes, but then it started to produce this nasty, harsh, gated clipping whenever I played hard. Still sounds nice when I play with a real light touch, but crappy when I really lay into it. Happens regardless of there the pots are. Only changes are that I made r5 switchable between 47k and 220k, and I used the "Wet" switch.
Anyone else have this problem? Did I mess something up when I switched the Depth lugs around? They were where the layout said they should be when the pot worked backward (more depth when pot was turned left, CCW).
Thanks!
Are you sure you have the depth pot wiring correct? Is R8 definately 47k? Is R9 definately 4k7? You can try removing R8 altogether, I found that too low a value for R8 caused the issue you have, but removing it and just varying the resistance between the LFO and the Iabc inputs of the OTA sounds almost as good. Too low a value for R9 can cause permanent damage to the Iabc inputs of the OTA.
I just checked, and I can confirm R8 and R9 are the correct values.
Quote from: frequencycentral on January 19, 2010, 09:37:32 AM
I found that too low a value for R8 caused the issue you have, but removing it and just varying the resistance between the LFO and the Iabc inputs of the OTA sounds almost as good.
This goes over my head a bit, sorry. Where exactly are you talking about varying the resistance? How would I do that, add another pot? What would happen if I just pulled R8?
Thanks for all the help!
When I had the depth pot wired according to the layout the pot worked backward. I switched lugs 1 and 3. Now the pot works normally, but I have that nasty gating distortion when I play hard. I didn't have it before when the depth pot worked backwards. Did I mess something up?
Bump. Any thoughts?
Thy removing R8. That's the 47k resistor just above the NE5532 in the vero layout. See what happens, report back!
Rick, AKA Perfus Magnus,
I finally had a free breadboard to give this circuit a try. I am having some confusion making sense of the schematic vs your layout, though. It looks to me like the Regen Lug 3 should connect to IC1 pin 9 on the schematic, but it it shown connecting to IC1 pin 8 on the layout?
Also, I am having a hard time figuring out which caps correspond to C9 and C10 on the schematic since they are both the same value. If I read the schematic right C9 should connect to IC1 pin 8, but in the layout it goes to IC2 pin 1? Similarly, C10 connects to IC2 pin 1 on the schemo but to IC1 pin9 on the layout.
Am I missing something? (I wouldn't be surprised...)
Thanks!
Docus Dropus
Hi Chris!
Quote from: doc_drop on January 22, 2010, 02:09:46 PM
Am I missing something? (I wouldn't be surprised...)
Quote from: frequencycentral on November 27, 2009, 01:51:30 PM
Here's the perf layout..........the only variance from the schematic is that I've used the two OTA's of the LM13700 in the opposite order, which just made the layout easier.
:icon_biggrin:
Like I said, I probably just missed something. :icon_redface:
So switching which OTA's is what accounts for the pin differences. Cool. I'll go ahead and breadboard it per the layout, since that is how I will build it if I like it as much as I think I will.
Thanks, Rick!
Chris, as you're about to breadboard it, PM me when you've got it up and running. I've a couple of ideas I'd like you to try which could make for interesting additions.
With pleasure. Now I have to make sure I do get it up and running, though.
Uh, I don't work well under pressure, man.... But, I'll give it my best. :icon_biggrin:
Pulled out R8. I think it actually made it worse, and it messed up the depth control, it hardly did anything and the max depth was way less.
O.K. I got this guy breadboarded. I would have had it done yesterday, but I ran into a little issue translating the OTA connections from the perf layout to the schematic then to the breadboard. A little debug this morning, and it is sounding awesome.
I changed R5 to 100K, because I like the sweep better. I am considering trying a pot here for fun. And the Regen pot works much better for me at 10K log. I get into feedback at the right at the end, so I have a wide range to play with.
Now, what were those mods you mentioned, Rick?...
Quote from: doc_drop on January 24, 2010, 03:46:10 PM
Now, what were those mods you mentioned, Rick?...
PM'ed!
Has anyone who has built this found that the effected signal is a little less than unity? My band has just started rehearsals again after a long break, and I guess playing louder than I do at home has made me notice. I've ended up replacing R12 with a 47k resistor (was previously 100k), that's sorted it out. The other option is to leave the existing R12 in place and just add another 100k in parallel with it.
Sometimes I find that setting up a new effect for unity gain is tricky, it can be so subjective depending on the environment, the percieved volume of the effect, and how loud you are playing. I guess the solution would be to make sure the effect is slightly louder than unity and then make the resistor to ground at the output into a trimpot so folks can set it to their own version of what unity is to them.
Anyway - anyone ready for Causality 4 MkII? More knobs, more control! doc_drop has it on his breadboard right now, we've been PM'ing back and forth all week, he's been kind enough to implement and fine tune some of my ideas for an uber 5 knob version. The extra controls add adjustable up and down sawtooth in addition to triangle from the LFO, as well as an LFO width control. The original version's depth control was really a range control, defining where in the audio spectrum the phasing takes place, the new width control defines how wide ( :icon_lol: ) the LFO sweep is. We're just finalising the mods at the moment. More to come...................
:icon_biggrin:
Quote from: frequencycentral on January 29, 2010, 01:55:36 PM
Has anyone who has built this found that the effected signal is a little less than unity? My band has just started rehearsals again after a long break, and I guess playing louder than I do at home has made me notice. I've ended up replacing R12 with a 47k resistor (was previously 100k), that's sorted it out. The other option is to leave the existing R12 in place and just add another 100k in parallel with it.
Sometimes I find that setting up a new effect for unity gain is tricky, it can be so subjective depending on the environment, the percieved volume of the effect, and how loud you are playing. I guess the solution would be to make sure the effect is slightly louder than unity and then make the resistor to ground at the output into a trimpot so folks can set it to their own version of what unity is to them.
Anyway - anyone ready for Causality 4 MkII? More knobs, more control! doc_drop has it on his breadboard right now, we've been PM'ing back and forth all week, he's been kind enough to implement and fine tune some of my ideas for an uber 5 knob version. The extra controls add adjustable up and down sawtooth in addition to triangle from the LFO, as well as an LFO width control. The original version's depth control was really a range control, defining where in the audio spectrum the phasing takes place, the new width control defines how wide ( :icon_lol: ) the LFO sweep is. We're just finalising the mods at the moment. More to come...................
A 100k pot in series with the 68k across the last opamp before the output of this schematic: http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PhaserRev10.jpg will take you anywhere volumewise.
frequencycentral in association with doc_drop are proud to present "Causality 4" MkII:
What's new:
- Width pot added, this defines how broad an LFO sweep the OTA's see
- Shape pot added, waveform now continuously variable from upward sawtooth through triangle to downward sawtooth
- The original Depth pot has been re-named as Range, and defines where in the audio spectrum the phasing happens
- Regen pot is now 10k log for a more useful range
- Speed pot is now 470k rev log for a more useful range
- R7 reduced from 10k to 4k7 for faster maximum speed
- R12 reduced from 100k to 47k to correct the gain structure
- R5 increased from 220k to 330k
- I've switched the two OTA stages around in the schematic to match up with the perf/PCB layouts
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkII.jpg)
Chris (doc_drop) has been good enough to breadboard the original circuit and implement some mods I had in mind, he's done some great work fine tuning and tweaking them to perfection, massive respect to Chris for taking this on! He's even provided some soundclips of his breadboarded circuit in action, I believe he's perf'ing it up right now. I'm pretty much stoked with how this turned out, I need to order some parts before I can get my MkII together. How cool is the internet, that two guys living over 5000 miles apart can work on something like this together???
I'm just putting the finishing touches to the MkII perf and PCB layouts, actually pretty close to the original layouts, and I'd even say that anyone with a MkI should be able to mod it to MkII spec without too much fuss. If you're not sure, just ask and I'll point you in the right direction.
The original concept for Causality was to create an 'easy build' good sounding phaser, which I think the MkI still is. MkII takes it a step further, more options and sonic variation, more knobs, more offboard wiring. The really cool thing is that the new PCB layout will be able to be used to build either a MkI or a MkII, you could even build a MkI on it and later mod it to MkII spec without to much fuss.
To round off, here some very entertaining soundclips kindly provided by doc_drop, I'll be adding my own soundclips too when I get the chance. Take it away doc!
Clean clip: http://dl.dropbox.com/u/967492/DROPed-Cause-01-31-10.mp3
Dirty clip: http://dl.dropbox.com/u/967492/DROPed-Cause-Thru-Fuzz-01-31-10.mp3
Yep, I have this bad boy working on perf now. I am no Frequency Central when it comes to the neatness of my perf builds, so it took a fair amount of debugging to get the kinks ironed out, but the schematic is now verified, and the perf build is really close to the layout FC already posted.
If you want to build a phaser, I highly recommend this one. It has a wide range of sounds. As I said to FC, it is somewhere in between the ROG TriVibe I recently built and FC's Phase Revolution. But it has a certain "je ne sais quoi" that makes this a sweet little phazing, chorusing, vibing, outer spacing circuit!
And not having to match trannies is a huge benefit. (No, don't put quote that in your signature, you pervs!)
doc_drop
I will be revising my causality4 to an mkII!! I love the original, looking forward to play with the MKII!!!
Thanks Rick and Chris!!!
And I will revising my signature!!! :icon_lol:
Here are some pics of the development process. My breadboard has never been so full, and so useful!
Breadboarding:
(http://img.villagephotos.com/p/2009-2/1335875/IMG_2755.JPG)
(http://img.villagephotos.com/p/2009-2/1335875/IMG_2754.JPG)
On Perf:
(http://img.villagephotos.com/p/2009-2/1335875/IMG_2759.JPG)
P.S. I knew somebody would enjoy my humor, Renegadrian! ;)
Looks awesome! MKI was already on my to do list, looks like I need to look into ordering more knobs.
Quote from: doc_drop on February 04, 2010, 09:19:40 AM
(http://img.villagephotos.com/p/2009-2/1335875/IMG_2759.JPG)
I'm mystified as to why your perfboard is a mirror image of mine. I thought you lived on the other side of the planet, not on the other side of the Sun (http://en.wikipedia.org/wiki/Doppelg%C3%A4nger_(1969_film))!
I'm actually from a mirrored galaxy only accessible through the worm hole of a Microsoft Operating System. That and you'll notice from the mirrored text that I did in fact mirror this image just to throw Star Fleet off my trail!
Phazerz on KILL!
Oh, and I remember vivedly seeing that movie when it first came to US TV. It made a big impression on me.
I have modified the vero layout to the MkII version. It's getting a bit tight down in LFO corner. I havn't replaced the MkI layout, that's still here.
A few moved components and extra trace cuts, if your upgrading from MkI. Most notably the jumper at x16/y16 needs removing. This means having to desolder the opamp, no way around that I'm afraid. The trace cut at z10 will need jumpering (z9/z11), this has not been shown here so bear that in mind. Watch for the trace cuts at v6 and z17.
I've taken the Vref to the inverting input from the divider at the LFO by means of a wire across the board.
Unverified as yet but will update once I've completed it.
In the pipeline is an extra stages board, the connections to which i've included on this and the original Mk1 layout. Hopefully to appear sometime over the coming week.
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20MkII%20Phaser%20Stripboard.gif)
I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?
Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.
Quote from: sundgist on February 06, 2010, 10:10:46 AM
I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?
Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.
I'm curious about that too. In my imagination using LEDs would give a visual indication of the waveshape. I hope it works out like that. :) Please do break it out onto breadboard and report back. I'm just guessing, but maybe as LEDs have a higher forward voltage the shape pot could be a lower value.
Quote from: frequencycentral on February 06, 2010, 10:17:05 AM
Quote from: sundgist on February 06, 2010, 10:10:46 AM
I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?
Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.
I'm curious about that too. In my imagination using LEDs would give a visual indication of the waveshape. I hope it works out like that. :) Please do break it out onto breadboard and report back. I'm just guessing, but maybe as LEDs have a higher forward voltage the shape pot could be a lower value.
I'll give it a go.
I actually tried with LED's. It didn't change the wave shape response very much. And the LED's barely lit up at all. I was looking for a place to add a rate LED. I tried in a few locations, but either the signal wasn't strong enough to light them, or it sucked tone in a massive way. I gave up after not too much trying...
If anyone can figure out a rate LED technique, please share!
:icon_biggrin: MkII vero layout is verified working. :icon_biggrin:
and I'm liking this a lot. Thanks to the both of you for working this out.
I've been having a play with the LFO shape diodes, swapping between diodes and various LEDs. A pot whose taper spreads out both extents of a pots travel and bunching up in the middle would be ideal for the shape pot as it does little for most of the central part of it's travel. Using LEDs instead of diodes you can get visualisation of the LFO waveform, in the centre of the pot they flash with equal duration, at either extent one will stay on longer than the other, fading nicely. There are some compromises. :(
Firstly with the stock 1M pot you only get the lowest forward voltage leds (1.6 in my case) flashing at each extent of the pots rotation. Not really visible unless the lights are out. In the centre of the pot both flicker dimly. Possibly low current hi-brite types may be better but I only used what I had.
Lowering the pot to 500k, 100k, 50k, 10k gives more and more light from the leds and the waveshape is quite clear. Unfortunately the lower the pot, the faster the slowest speed. So much so that even at 500k a lot of the slow range I like is lost, and the led show is a bit feeble.
I still like the idea of having the LFO represented visually. Unless I pick up some low current LEDs to try, I will be looking at keeping the diodes and pot as stock (with an ideal taper if possible) and just buffering some leds. I've already got one led running off the opamp output, but preferred seeing the rising and falling sides of the waveform working together.
Quote from: doc_drop on February 06, 2010, 08:13:47 PM
I actually tried with LED's. It didn't change the wave shape response very much. And the LED's barely lit up at all. I was looking for a place to add a rate LED. I tried in a few locations, but either the signal wasn't strong enough to light them, or it sucked tone in a massive way. I gave up after not too much trying...
If anyone can figure out a rate LED technique, please share!
I've got an extra bright LED running from the output of the opamp (output to the range pot) via a 3.9k resistor to gnd using a millenium 2 bypass. I'm using it as a bypass led. This fades in and out nicely, there are no pops and doesn't affect the sound in any way. Can't see why it should it's not in the audio path here. I don't know what it might be doing to the LFO waveform, haven't hooked a scope up to it, but if anything it's certainly not audible. I tried with a few different types of led, some worked better than others and with different value series resistors.
Glad to hear it sundgist. I think it is a pretty cool circuit myself.
I'll have to give your rate LED solution a shot. I am getting ready to put this in a box, so now would be a great time to get the rate LED working.
Now, set that phaser on stun and enjoy playing! (That's what my morning entertainment is going to be...)
QuoteI've got an extra bright LED running from the output of the opamp (output to the range pot) via a 3.9k resistor to gnd
That works perfectly sundgist. Thanks.
I think I tried that while breadboarding, but I probably didn't pay good enough attention since I was really concentrating on other things.
I used a 2k2 resistor and an extra bright green LED, FYI. Call me cheezy, but I love a nice blinking LED that reflects the changes to the LFO. It is nice to see sawtooth up/dn versus triangle as you make changes to the settings... :D
If you use another LED the opposite polarity (with it's own resistor) and hook it up to +ve instead of ground, it will be the mirror image of the first LED. As one fades out the other will fade in. :D
Quote from: frequencycentral on February 07, 2010, 02:59:44 PM
If you use another LED the opposite polarity (with it's own resistor) and hook it up to +ve instead of ground, it will be the mirror image of the first LED. As one fades out the other will fade in. :D
Works for me. ;D
Thanks, hadn't even crossed my mind.
O.K. I now have extra bright blue and green LEDs flashing alternately. It is one of the sexiest things I ever saw!
This is definitely going to be a part of my final build. My inner child is smiling a huge smile right now. And somehow this level of fancy lights seems right for such a cool circuit.
Thanks for the tips guys! :icon_biggrin:
Here's the artwork for the 5 knob MkII PCB, it includes pads for the addition of an extra stages daughter board - more on this some other time! The 3 knob MkI version can also be built using this layout.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIPCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIPnP.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/WaxnWane.jpg)
Quote from: doc_drop on February 08, 2010, 09:14:21 AM
O.K. I now have extra bright blue and green LEDs flashing alternately. It is one of the sexiest things I ever saw!
This is definitely going to be a part of my final build. My inner child is smiling a huge smile right now. And somehow this level of fancy lights seems right for such a cool circuit.
Thanks for the tips guys! :icon_biggrin:
I'm sat in a darkened room at 1 o' clock in the morning, have been noodling away on my guitar for the past hour, watching the lightshow. 8) Been messing about with some rhythmic plonking by setting the regen near max, range at min, falling sawtooth and letting the bass strings ring while playing up on the higher strings.
I'm finding it a lot easier and quicker dialing in the right speed and shape with a visual cue. The LEDs are a lot more interactive than I expected, reacting to the width control as well.
Gave the resistors a bit of fine tuning to balance the brightness between them and get the right amount of fade.
I find it funny that we have people here painstakingly biasing their fuzzes just right, finding new ways to get 'that' sound, filling boxes with rare mojo components, and I'm over the moon with a pair of flashing lights :icon_biggrin:
...............time for bed I think, I need to get my baggy eyes to work in a few hours.
Quoteand I'm over the moon with a pair of flashing lights
Well, at least I'm not entirely alone in the world. :icon_razz: It is completely cool and actually useful to see the LEDs do their work.
In hindsight, it would have been useful to have this set up while breadboarding...
2 and 4 extra stages vero layouts. Will be verified when built, but should be OK.
Can anyone answer a thought I had while drawing these out. What effect would wiring a different LFO to some stages have? Wierd multi modulated phasing ???
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20+2stages%20Stripboard.gif)
(http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20+4stages%20Stripboard.gif)
Nothing new to add. Just some pics of my finished product. Unfortunately the lettering got dark during finishing. But I like the Star Ship Enterprise caught up in a "Causality" in the middle...
(http://img.villagephotos.com/p/2009-2/1335875/Causality-DROP-montage.jpg)
All good phasers deserve a Star Trek themed graphic, I've got a nice one done for my MkII. Though it seems that I'll be modding and rehousing my MkI rather than building a fresh one, as no one wants to buy my MkI prototype (http://www.diystompboxes.com/smfforum/index.php?topic=82482.0). :'(
.....and it seems I should put together a perf tutorial! ;)
As always, I cannot recommend the "phase-filter" mod highly enough. It is derived from the original Blacet Phase-filter module, that is described and emulated here: http://hammer.ampage.org/files/Device1-6.PDF
The mod consists of taking the 3300pf caps that are tied to pins 10/12 and 5/7 on the LM13700, and rerouting their other end (i.e., the end that would normally be tied to pin 8 or 9 of the stage before it) to ground. This transforms the allpass stage to a lowpass stage. You would, of course, really need a minimum of 4 swept stages to do this, since 2 would need to be swept allpass (producing a notch), leaving 2 to be lowpass. Simply having 2 swept and 2 fixed stages will not make the unit eligible for this mod.
What does it do, or sound like? When combined with clean signal, Craig Anderton appropriately describes it as adding "animation". It really comes alive, however, when the clean signal is lifted and all you have is the combination of allpass and lowpass. Under those conditions, what you get is a bizarre mélange of what sounds like vibrato, tremolo, and autowah at the same time. The vibrato, arising from allpass-only, makes sense. The LFO modulated lowpass sounding like an autowah also makes sense. And because of the way in which filtering out the treble results in shifts in apparent loudness, it sounds a bit like tremolo. The overall package is best described as sounding "swampy" and syrupy. It oozes mojo if your LFO has the right properties.
Note as well that, with the resonance turned up, the filtering really stands out. With the resonance eased back, and a slow sweep (and a rising ramp would be perfect for this), it can produce some wonderful synth-pad-like tones. Stick a bit of chorus on it, and you're cooking.
Finally, I will note that the frequency range where notches are produced might be different than the frequency range where the lowpass filtering sounds best to your ears. What I have done in some instances is leave a pair of 3300pf caps connected to pins 8 and 9, leave another pair of 2700pf caps tied to ground, and simply switch the pin 10/12 and pin 5/7 connection between the free end of either cap, such that in phaser mode the cap values are all 3300pf and in phasefilter mode you haveallpass stages using 3300pf and lowpass using 2700pf.
Try it. You'll like it. I promise.
Charlie Barth has a few clips of a Small Stone with the mod, although personally I think it doesn't quite do justice to the range of tones obtainable. http://moosapotamus.net/THINGS/frankenstone.htm
Wow. Sounds interesting.
Looks like I'll be fitting in a few mods to the extra stages board!
I've really held off boxing this up. Good job too with all these extras.
This project seems to keep growing and growing.
Quote.....and it seems I should put together a perf tutorial!
Hey, I resemble that comment. No need to be a snob! :icon_evil: :icon_biggrin:
Now go clip some leads, show off...
I've just finished this phaser, and sadly it is not working. The bypass works fine, the LED is fine, the signal even gets through and gets some sort of phasing, but it is not affecting the signal of the guitar, more of just a background up and down white noise sound. I did the waxing and waning LEDs mod, and only one of them lights up. It is the one that is going to ground. This leads me to suspect that this is where something has gone wrong, but I'm not sure. I have the IC voltages here-
LM13700
1.) 1.33_ 9.) 1.33
2.) 0 ___ 10.) 0
3.) 3.65 _ 11.) 3.65
4.) 4.1 __ 12.) 3.95
5.) 5.15 _ 13.) 5.15
6.) 0 ___ 14.) 8.19
7.) 5.15 _ 15.) 5.15
8.) 4 ___ 16.) 0
TL084
1.) 4.05 _ 8.) 4
2.) 4 ___ 9.) 4
3.) 3.66 _ 10.) 3.5
4.) 8.17___11.) 0
5.) 1.8 __ 12.) 3.8
6.) 4 ___ 13.) 4
7.) 4 ___ 14.) 4
NE5532
1.) 4.23 __ 5.) 0
2.) 5.1 ___ 6.) 4.62
3.) 4.64 __ 7.) 4.63
4.) 8.3 ___ 8.) 5.03
Thanks!
Here's a picture of mine. I etched a board and soldered it up the other night.
http://www.super-freq.com/?p=256
Bump: Any ideas?
Quote from: Spidermonkey on March 22, 2010, 11:44:06 PM
Bump: Any ideas?
Your voltages look confused. I hope I don't come across as rude or condescending, but are you sure you understand the IC's pinouts, and which end is which? You said on BYOC:
Quote from: spidermonkeySadly, I only have one TL084. But after checking the data sheet, it turns out that pin one is on the side with the cutout, not the dot on the chip, so I did have it in backwards. Looks like I'll be placing another mouser order. This leads me to think, though, the NE5532 that I used also has both a cutout and a dot, and it seems that is in backwards. Would that be fried too?
The way you have laid out the voltage info suggests you need some help with this before we proceed further. Here's the NE5532 for example:
(http://www.syntax.com.tw/proddata/IC/IC-NE5532.JPG)
Pin 4 should read 0v, pin 8 should read 9v.
Here's datasheets (with pinouts) for the chip used in this effect:
http://www.datasheetcatalog.org/datasheet/fairchild/NE5532.pdf
http://www.datasheetcatalog.org/datasheet/texasinstruments/tl084.pdf
http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS007981.PDF
Hope this helps as a first step to getting your pedal debugged.
Ahh... I have the pinouts as counting down on the right side instead of up. Thanks for the help! Here are the corrected voltages-
LM13700
1.) 1.33_ 16.) 1.33
2.) 0 ___ 15.) 0
3.) 3.65 _ 14.) 3.65
4.) 4.1 __ 13.) 3.95
5.) 5.15 _ 12.) 5.15
6.) 0 ___ 11.) 8.19
7.) 5.15 _ 10.) 5.15
8.) 4 ___ 9.) 0
TL084
1.) 4.05 _ 14.) 4
2.) 4 ___ 13) 4
3.) 3.66 _ 12.) 3.5
4.) 8.17___11.) 0
5.) 1.8 __ 10.) 3.8
6.) 4 ___ 9.) 4
7.) 4 ___ 8.) 4
NE5532
1.) 4.23 __ 8.) 0
2.) 5.1 ___ 7.) 4.62
3.) 4.64 __ 6.) 4.63
4.) 8.3 ___ 5.) 5.03
Quote from: Spidermonkey on March 23, 2010, 06:10:59 PM
NE5532
1.) 4.23 __ 8.) 0
2.) 5.1 ___ 7.) 4.62
3.) 4.64 __ 6.) 4.63
4.) 8.3 ___ 5.) 5.03
Quote from: frequencycentral on March 23, 2010, 04:16:48 PM
Pin 4 should read 0v, pin 8 should read 9v.
After going back and remeasuring voltages, it turns out that pin 4 of the NE5532 is in fact 0v and pin 8 is 9v. And now pin 7 is about 2v instead of 4.62v. Pin 9 of the LM13700 is also now getting 2 or 3 volts, and I'm not sure why, as i previously had it at 0. My circuit is out of the box now, so could something be shorting?
Thanks for all the help :)
What I do when I get to this point, and I haven't been able to solve my problem with an audio probe, is print a clean schematic and go through it point by point, connection by connection for continuity with my DMM. And I also check adjacent traces, etc., for continuity where it shouldn't be. I highlight the checked areas on the schematic as I go along to make sure I don't miss something. And I measure each resistor to make sure it is the correct value. I have almost always been able to isolate and fix the problem like that.
It sounds to me like with all the confusion about pins it would have been very easy to get something wrong there. (I am sure I would have!)
Hmm... all of the 27k resistors I installed have the right color bands, but they are measuring around 10k on my DMM, rather than 27k. This seems really really wide for the tolerances, so could that be my culprit?
Quote from: Spidermonkey on March 24, 2010, 05:48:01 PM
Hmm... all of the 27k resistors I installed have the right color bands, but they are measuring around 10k on my DMM, rather than 27k. This seems really really wide for the tolerances, so could that be my culprit?
My bet is that if you measure them before installing on the board, they`ll read very close to 27k!
QuoteMy bet is that if you measure them before installing on the board, they`ll read very close to 27k!
True that. I should have mentioned that if there is any other componant with resistance in parallel with the resistors in the circuit, you can't measure them with a DMM without disconnecting one side. I would assume the color bands are correct, but I know I have made mistakes thinking the red band is orange, etc., so be careful...
Okay, that makes sense. I measured others in the bunch that I got them in, and they are all very close to 27k. I disconnected all the wires, so i can really go through the board and check everything. Wish me luck!
I just built this pedal. However, I am experiencing a huge volume drop. Should I replace the 68k resistor with either a trimpot or something with a resistance around 100k?
Quote from: in3x0rable on March 29, 2010, 07:35:19 AM
I just built this pedal. However, I am experiencing a huge volume drop. Should I replace the 68k resistor with either a trimpot or something with a resistance around 100k?
What values are you using for R10 and R12?
Ok, Rick, I bit on this project--I've been reading through this monstrosity of a thread, and I have a couple questions now that I'm populating my board--
1. I didn't see anywhere what the diode values should be--I'm assuming an 1n4148 or similar will do the trick. Can you confirm?
2. I don't have any 27k resistors, so I subbed 22k. Do you see any immediate issues with this? I also have some 33k resistors if the 22k won't work.
3. There was some mention with trouble w/ ICs other than the specified ones. I've got 4558s and TL072s, and I have TL074s instead of the specified opamps. I guess this isn't really a question, but I'll be sure to report in if I have any trouble using unspecified ICs.
Thanks to Rick for putting this project together, and thanks to all who put their work into it--layouts, mods and whatnot :) I can't wait to get this thing up and running!
Hi Josh,
The diodes can be 1n4148. 4558 or TL072 is fine for the LFO. Not sure about the TL074, should work, but socket it just in case!
Not sure about the resistor subs either. I seem to remember when I breadboarded it I used some 22k until my 27k arrived. Didn't notice much difference at the time. Go for it maybe, if you run into issues you'll know where to look!
Quote from: frequencycentral on March 29, 2010, 10:50:59 AM
Hi Josh,
The diodes can be 1n4148. 4558 or TL072 is fine for the LFO. Not sure about the TL074, should work, but socket it just in case!
Not sure about the resistor subs either. I seem to remember when I breadboarded it I used some 22k until my 27k arrived. Didn't notice much difference at the time. Go for it maybe, if you run into issues you'll know where to look!
Right on--thanks for the reply. I'll ring in here with what I've got in a couple days :)
QuoteWhat values are you using for R10 and R12?
I believe 10k. I built it to the specs of Revision 1.3.
Quote from: in3x0rable on March 29, 2010, 03:33:23 PM
QuoteWhat values are you using for R10 and R12?
I believe 10k. I built it to the specs of Revision 1.3.
Neither R10 or R12 are 10k, they are 68k and 47k respectively. What layout are you using?
OK, anyway, you built a MkI from the schematic on page 1 of this thread. Change the 100k resistor (that goes from the -ve input of the output stage to ground) for a 47k. That's R12 on the perf/PCB layout. This was corrected in MkII.
http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard%20Corrected.gif
Actually, I built it from that diagram if it changes anything. But I see which resistor I need to change. Thank you very much.
I was assuming that the 68k resistor controlled the output volume?
Here's my new MkII:
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0011-5.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0033.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0002-28.jpg)
Rick,
That is a flippin' beautiful build! Are you liking the improvements we worked on? Have you tried it out in rehearsals yet?
Mine sounds great, but it sure doesn't look as beautiful as that!
Hey Chris, just finished it today and had an hour to play with it before Mrs FC demended 'my immediate attention'......... The extra controls are really useful, particularly the width pot. I socketted R5 and R33 as I want to experiment with those two values, currently I've got 22k and 220k respectively (you used 10k and 330k), I'll try your values though, as the LFO isn't quite symettrical in the mid position of the shape pot. I'm also going to change the speed pot from 470k to 1M to go slower. You might notice I added a trimmer in place of R12, as I really wanted to get the volume perfect.
Quote from: frequencycentral on April 01, 2010, 03:20:34 PM
Hey Chris, just finished it today and had an hour to play with it before Mrs FC demended 'my immediate attention'......... The extra controls are really useful, particularly the width pot. I socketted R5 and R33 as I want to experiment with those two values, currently I've got 22k and 220k respectively (you used 10k and 330k), I'll try your values though, as the LFO isn't quite symettrical in the mid position of the shape pot. I'm also going to change the speed pot from 470k to 1M to go slower. You might notice I added a trimmer in place of R12, as I really wanted to get the volume perfect.
You used entirely too many periods there...
Quote from: jacobyjd on April 01, 2010, 03:27:01 PM
Quote from: frequencycentral on April 01, 2010, 03:20:34 PM
Hey Chris, just finished it today and had an hour to play with it before Mrs FC demended 'my immediate attention'......... The extra controls are really useful, particularly the width pot. I socketted R5 and R33 as I want to experiment with those two values, currently I've got 22k and 220k respectively (you used 10k and 330k), I'll try your values though, as the LFO isn't quite symettrical in the mid position of the shape pot. I'm also going to change the speed pot from 470k to 1M to go slower. You might notice I added a trimmer in place of R12, as I really wanted to get the volume perfect.
You used entirely too many periods there...
I can assure you the number of periods used was entirely appropriate......... :icon_redface:
Quote from: frequencycentral on April 01, 2010, 10:33:46 AM
Here's my new MkII:
Very nice.
Would the empty half of the enclosure be intentional? Extra stages with Mark Hammers phase filter?
Mine is still out on the work bench. Havn't had the time to put it in a box yet, or try out adding the extra stages.
Quote from: sundgist on April 01, 2010, 05:28:15 PM
Would the empty half of the enclosure be intentional? Extra stages with Mark Hammers phase filter?
It does look that way doesn't it? Though it wasn't the intention, it was just the best way to mount the board.......but now you mention it, I have left my options open haven't I?!
After playing about with my MkII I've done the following tweaks to get it how I like it:
R5 at 220k appears to me to keep the LFO symettry. I increased the value of C4 (the timing cap) because the addition of the shape control has the effect of approximately doubling the minumum available speed. I like very slow phase sweeps, so I played around with paralleling different value caps with the existing C4, I really liked the sweep with a 33uF in parallel, so I'm going to sub a 47uF for the existing 10uF. The fastest speed is now slower though, so it's a trade off.
Managed to get some time to work on this again, trying to cram it into an enclosure and leave a bit of space for the extra board.
Noted a few fixes on my layout while looking at a few things on the o-scope. Layout has been updated.
Taking vref on the lfo buffer/gain stage from the lfo's voltage divider causes the lfo to swandive just before it gets to each positive and negative peak. I've moved the 10k resistor and wire along a bit and added a link to the main power supplies vref. Also noticed the lfo is getting clipped as the width control goes past halfway. Making this 10k resistor larger limits the gain and stops the flats at the top and bottom of the lfo. I've switched mine to 47k. Saying that, adding more gain here gets the lfo looking more square which can give some interesting effects.
I have a question about the wax and wane LEDs. I dont fully understand the schematic.
(http://i210.photobucket.com/albums/bb292/frequencycentral/WaxnWane.jpg)
What does the top arrow connect to?
I'd also like to thank everyone who worked on getting this build to where its at and providing the layouts. Can't wait to get this running.
Quote from: solfin on April 21, 2010, 11:59:41 PM
What does the top arrow connect to?
The top arrow indicates the +ve voltage connection, ie 9 volts.
Oh! So you have another wire connecting Range 3 to the board?
Quote from: frequencycentral on April 22, 2010, 01:14:40 PM
Quote from: solfin on April 21, 2010, 11:59:41 PM
What does the top arrow connect to?
The top arrow indicates the +ve voltage connection, ie 9 volts.
I did do a quick search for circuit diagram symbols and couldn't find an arrow used like that. Thanks for explaining.
Quote from: frequencycentral on November 22, 2009, 04:48:13 PM
The go-to phaser builds for DIY'ers are:
Phase 45 – Intermediate build. 2 stages. FET matching required. No regen. Very subtle.
Phase 90 – Advanced build. 4 stages. FET matching required.
Ross Ropez – Advanced build. 4 stages. OTA design.
Small Stone – Advanced build. 4 stages. OTA design.
The design concept for "Causality 4" was to achieve a musically useful intermediate build 4 stage phaser with regen, using easily available parts, and requiring no matching of components. It has two swept stages using a dual OTA, and two fixed stages using opamps. The LFO utilises a dual opamp and is based on the MXR phasers, much simpler than the LFOs in either the Small Stone or Ross Ropez. The fixed stages came from an idea suggested by Mark Hammer in this thread: http://www.diystompboxes.com/smfforum/index.php?topic=80111.0 Having four stages, even if two are fixed, allows for the addition of regen, which for me is a phaser essential. The Regen control goes from zero to just short of self oscillation - some great sounds available here. The Depth control is particularly interesting and useful, specifying where in the spectrum the phasing occurs.
Your critiques are welcome!
Soundclips, perf and PCB layouts to follow .....
this thread is just cooler than cool can be ! :icon_mrgreen: .... i'm putting this project on my "must-build-in-the-future" list .... pardon me while i go source some chips !! :icon_mrgreen:
Ok--After adding one forgotten jumper, I finally got my C4 up and running. It sounds pretty good, despite the fact that I wired all the pots backward :icon_rolleyes:
However, the one major issue it does have is that the output with the effect on is WAY low. Any ideas on what could be causing this? I haven't taken any voltages yet, because I finished it just before bed last night. However, given that it functions perfectly all around except for the output volume, i'm thinking it might just need a couple resistor swaps.
Does that sound right?
I'm hoping to get back to it tomorrow evening, so I should have more info then.
Hey Josh, glad you got it up and running. The volume issue is something I (attempted to) addressed in the MkII. The volume is set by by R10 and R12 in combination (on the perf/PCB layout), the closer those two values are to each other the lower the volume. R10 should be a larger value than R12. On my MkII build I ended up using a 100k resistor for R10 and a 100k trimmer instead of R12 so I could adjust to unity without having to dink around with socketting resistors. How come all your pots are backwards? I did label them correctly right?
Other mods I made to my MkII:
- R5 = 220k
- C4 = 47uF (I just paralleled a 33uF with the existing 10uF)
- R33 = 47k
Quote from: frequencycentral on May 04, 2010, 01:01:57 PM
The volume is set by by R10 and R12 in combination (on the perf/PCB layout), the closer those two values are to each other the lower the volume. R10 should be a larger value than R12. On my MkII build I ended up using a 100k resistor for R10 and a 100k trimmer instead of R12 so I could adjust to unity without having to dink around with socketting resistors.
Fantastic--that's where I was thinking of looking first. You explain it in very practical terms. I'll fiddle around a bit when I get some time to dig into it again.
QuoteHow come all your pots are backwards? I did label them correctly right?
lol..yeah...I built the vero, and looking at the schematic, I can never tell which lug is which. Usually I orient myself to the layout by a volume control voltage divider pot at the output. Since there's not one here, I was counting on the 50/50 chance to fall in my favor :icon_redface: Not so much this time :)
However, it's all pretty tightly wired. I'll probably re-do it all anyway, given the resistor swaps I'll need to do.
Quote from: jacobyjd on May 04, 2010, 01:15:08 PM
Fantastic--that's where I was thinking of looking first. You explain it in very practical terms. I'll fiddle around a bit when I get some time to dig into it again.
Thanks! If you've built a MkII those two resistors are 68k (r13-s13) and 47k (k19 - r19).
Quote from: jacobyjd on May 04, 2010, 01:15:08 PM
lol..yeah...I built the vero, and looking at the schematic, I can never tell which lug is which. Usually I orient myself to the layout by a volume control voltage divider pot at the output. Since there's not one here, I was counting on the 50/50 chance to fall in my favor :icon_redface: Not so much this time :)
That's a 'blind spot' I recently conquered myself. Looking at the back of the pot with the lugs pointing down, lug 1 is on the right. I'm just doing a build with a two knob Vox tonestack, I fully expect them to work backwards. ::)
Yeah, the problem I run into there is that it's not always universal :( I'll know for your layouts in the future though :)
:icon_redface:
I never remember which way pots are numbered. 2 is always the wiper. I tend to label 1 & 3 depending on which way round the symbol is on the schem. Then when wiring I go for 'pot' luck and if I have to reverse anything so be it. At that point I'll forget whether the labels on the layout were right or not.
Ok--I put a 100k in parallel with the 68k resistor and it solved the volume issue (now it's too loud--i'll be adding a trimmer in its place)
I'll see how things sound when I rewire the pots--however, I'm getting a crazy thumping sound that occurs when the depth and speed are increased. I'm assuming it's mainly an issue of how wide the phasing sweep is, given how fast it has to make the sweep. It's pretty radical, but I think it'll settle down when i have all my tapers correct.
Other than that, it's pretty sweet--looks like i'm one decent evening away from getting it tweaked and boxed up :) Liking the design!
just finished putting the Mark I circuit together on veroboard .... and it sounds really interesting ... ;D ..... you guys did a really good job with this shifter ..... i plan to put a Mark II together in the future .... and i'll post some soundclips of the Mark I later this week ....
one question: will the Mark I work on 12 volts?
Quote from: stringsthings on May 23, 2010, 06:56:39 PM
just finished putting the Mark I circuit together on veroboard .... and it sounds really interesting ... ;D ..... you guys did a really good job with this shifter ..... i plan to put a Mark II together in the future .... and i'll post some soundclips of the Mark I later this week ....
one question: will the Mark I work on 12 volts?
:icon_biggrin:
Yeah I run mine on 12v.
Still trying to debug mine... Would a 1M speed pot cause the phasing to only happen at the extreme CCW end?
most excellent :)
Quote from: Spidermonkey on May 23, 2010, 08:09:58 PM
Still trying to debug mine... Would a 1M speed pot cause the phasing to only happen at the extreme CCW end?
A 1M will work fine. To get the best out of it, it needs to be rev log though, no matter if you use 1M or 470k. A lin pot will cause bunching at the extreme CW. Not sure about log, maybe that's what you're using?
Ok cool. I'm using a rev log. The problem is that everywhere on the sweep of the pot, it sounds like the phaser is stuck, kinda like a stuck wah, and it only starts going up and down when I turn the speed all the way down.
soundclips of the Mark I
http://soundclick.com/share?songid=9192452/ (http://soundclick.com/share?songid=9192452/)
recording details: guitar with Seymour Duncan humbuckers ---> Mark I ---> line6 amp sim ( roland jc-120 with 4x10 bassman cab )
.... no other effects, hardware or software, were used in the recording .... [ as per instructions by my feline engineer, Lucky ;D ]
the Mark I build is pretty much verbatim from the 1.3 schematic ..... R12 changed to 47k as recommended .... regeneration pot = 47k ..... the build is not housed yet .... but it looks real purdy on the veroboard ! :icon_mrgreen: .....
... the phase shifting fun starts at 0:24 after the harmonics .....
Nice clip. The very end reminds me of the effect on John Paul Jones's keyboards at the start of 'No Quarter', which was actually a Hohner Electra-Piano processed through a VCS3. Must try to get that sound with my Rhodes through the Causality.
Quote from: frequencycentral on May 26, 2010, 01:42:23 PM
Nice clip. The very end reminds me of the effect on John Paul Jones's keyboards at the start of 'No Quarter', which was actually a Hohner Electra-Piano processed through a VCS3. Must try to get that sound with my Rhodes through the Causality.
Thank you.
I listened to the clips last night and the fact I couldn't recall what it reminded me of was bugging me.
Quote from: frequencycentral on May 26, 2010, 01:42:23 PM
Nice clip. The very end reminds me of the effect on John Paul Jones's keyboards at the start of 'No Quarter', which was actually a Hohner Electra-Piano processed through a VCS3. Must try to get that sound with my Rhodes through the Causality.
thanks for the comments. being anywhere near the sounds of Led Zeppelin is a great compliment. i'm planning on building the Mark II this summer and i'll be sure to post a clip ..... i think it's great how the DIY community has grown .... this phaser project is a wonderful example of the positive power of the internet .... [ back in college, i didn't know anyone else that was really into DIY .... no one to share my dream of owning an obscenely large number of fuzz boxes :icon_mrgreen: ]
Hey rick, would you mind putting up your voltages for the NE5532?
Thanks
Quote from: Spidermonkey on May 31, 2010, 05:48:22 PM
Hey rick, would you mind putting up your voltages for the NE5532?
Thanks
Sure, I'll post a full set of voltages for all the IC's tomorrow.
Thanks a lot man. It's bothering me how i just can't get this working right.
These are voltages from my MkII, using the PCB layout (although I used perf). Of course they are all jumping around like crazy as the LFO cycles, so I've recorded the minimum and maximum voltages for each pin.
Speed at minimum. Shape midway. The rest at maximum.
Supply voltage: 9.10v
NE5532
1. 1.32v to 8.44v
2. 3.56v to 5.81v
3. 3.45v to 5.77v
4. 0v
5. 3.56v to 5.84v
6. 3.55v to 5.85v
7. 2.89v to 7.02v
8. 9.10v
TL084
1. 3.89v to 5.34v
2. 3.87v to 5.37v
3. 3.85v to 5.30v
4. 9.10v
5. 3.63v to 5.02v
6. 3.87v to 5.33v
7. 3.87v to 5.33v
8. 3.87v to 5.33v
9. 3.87v to 5.35v
10. 3.85v to 5.31v
11. 0v
12. 3.87v to 5.33v
13. 3.88v to 5.33v
14. 3.87v to 5.33v
LM13700
1. 1.304v to 1.373v
2. 0v
3. 3.87v to 5.33v
4. 3.87v to 5.33v
5. 5.05v to 6.51v
6. 0v
7. 5.03v to 6.53v
8. 3.87v to 5.33v
9. 3.87v to 5.33v
10. 5.03v to 6.53v
11. 9.10v
12. 5.05v to 6.51v
13. 3.87v to 5.33v
14. 3.87v to 5.33v
15. 0v
16. 1.304v to 1.373v
EDIT @ 8.25pm: I've been pondering these voltages since I took them a couple of hours ago. I was somewhat surprised that pins that I had assumed would be static are in fact moving. The vref is moving. I've come to the conclusion that it might be that R33 referencing the vref is causing the vref to wobble. Forunately my R33 is socketed, so tomorrow I'm going to pull it and give it it's own vref and see what happens. I think the effect sounds great, but a vref is a vref and should be static, so I wanna find out what's happening.
Quote from: frequencycentral on February 08, 2010, 06:26:14 PM
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIPCB.gif)
I look at pots the same way you do....back of pot, legs down, left to right is 3-2-1. OK where do I hook up WIDTH 3?
**edit** looking at the schematic, I'm going to guess that width 2 is really width 3, and width 1 is also width 2...yes? /edit**
Thank you.
OK I wired it up. Don't have time to go get pin voltages at the moment, but I want to see if this specific set of symptoms point to anything in particular...
- bypass works 100%
- all knobs work, that is, do what I expect them to
- guitar signal passes thru when turned on, but does not seem to be particularly effected - this, to me, is the wierdest of the symptoms
- when the RANGE is turned up, I get a very loud thumpy signal, that can be directly effected for shape and depth and speed by the other knobs
No parts substitutions other than a 100k trimpot, which is obviously working, at R12.
It could be as simple as a pot wired wrong (see post above), for another example leg 1 of speed is not connected - wasn't sure if to run it to ground, or ground it to itself, or not.
Looking at the pad side of your perf, you have missed a vref trace, under R26. The vref connects m10 to o10, then continues up to k9.
Quote from: keto
(http://img.photobucket.com/albums/v374/keto/Pedal%20Builds/Phase5.jpg)
Hi Rick,
I built the MK2 based your pcb layout. I created the layout with ExpressPCB.
This is my layout (http://"http://forum.musikding.de/cpg/albums/userpics/24316/Image2.jpg").
The phaser works but it's oscillating. It's like a siren... I noticed that I build the phaser with a 1m Rev pot for regen.
The cuircit is oscillating with and without the regen pot. It's oscillating but it seems to work like a phaser. Every pot does it's job even if the guitar signal is not used :D
The voltages for the ICs are very similar to yours mentioned before. Except the regen pot every part is like the MK2 layout with your recommendations:
* R5 = 220k
* C4 = 47uF
* R33 = 47k
* R12 = 100k trim
What could be the reason for the self oscillation?
DUDE! Wow, man, I cannot BELIEVE you took the time to do that....my undying gratitude! (Side note - he took the time to go to another forum and pull down my perf picture. Beyond the call of duty? I guess so!) A simple 2 hole bridge, and I have a 100% functional phaser, thank you! Much respect, sir.
My next question, and hopefully last, has to do with the 'rotating' LED's. So,
(http://i210.photobucket.com/albums/bb292/frequencycentral/WaxnWane.jpg)
Is that saying this? (Do I even need R2, that is, will the voltage reduction of R1 continue to the 2nd LED or will being attached to Range 3 take it back into a full 9v circuit?) Having not tried it, I'm just scratching my head about running power 'backwards' thru the 2nd LED, and am not sure I am understanding the schem, as simple as it is.
(http://img.photobucket.com/albums/v374/keto/Pedal%20Builds/LEDwiring.jpg)
Thanks in advance.
Haha, because I thought you drew two penises, I will try to help you. 9v goes to the anode, which you drew, but you have Ra in the wrong position. Ra should be between the LED and lug 3. Then you have Rb, which looks good, but that connects to the anode of the second LED, where you have it to the cathode. Then switch the cathode to ground.
..I think
Quote from: mth5044 on June 11, 2010, 10:25:37 PM
Haha, because I thought you drew two penises, OMG my wife walked in the room with that pic on my desktop AND THOUGHT THE SAME THING geeze I'm no picasso but is it THAT bad? ROFL.
I will try to help you. 9v goes to the anode, which you drew, but you have Ra in the wrong position. Ra should be between the LED and lug 3. Then you have Rb, which looks good, but that connects to the anode of the second LED, where you have it to the cathode. Then switch the cathode to ground.
..I think
And so, as my artistic skills seem to be so amusing, I ask:
Thusly? But then won't both LED's turn on at the same time, there's no polarity change?
(http://img.photobucket.com/albums/v374/keto/Pedal%20Builds/LEDwiring2.jpg)
Seems as though I likely still want to run a resistor between 9v and the first LED, or does R1 really stop the juice from hitting the LED full force?
I'm not sure how it's working, I didn't really look at the big picture, but basing off of that little schematic clip you posted, I think your last pictures is right. How it works, I dunno. Maybe Ra(1) isn't connecting to 9v but to another Vref or something? I'm sure Rick will save the day in a bit.
Quote from: tuckster on June 11, 2010, 04:50:22 PM
Hi Rick,
I built the MK2 based your pcb layout. I created the layout with ExpressPCB.
This is my layout:
(http://forum.musikding.de/cpg/albums/userpics/24316/Image2.jpg)
The phaser works but it's oscillating. It's like a siren... I noticed that I build the phaser with a 1m Rev pot for regen.
The cuircit is oscillating with and without the regen pot. It's oscillating but it seems to work like a phaser. Every pot does it's job even if the guitar signal is not used :D
The voltages for the ICs are very similar to yours mentioned before. Except the regen pot every part is like the MK2 layout with your recommendations:
* R5 = 220k
* C4 = 47uF
* R33 = 47k
* R12 = 100k trim
What could be the reason for the self oscillation?
A quick check over your layout shows the same missing trace under R26 as in
keto's build. I know it's difficult to see on my PCB layout, but if you compare your layout to my PnP you'll see what I mean. Fix that trace, then report back, if you're still having problems I'll look at it again.
The wax/wane LED thing definately works as drawn (by me). One LED is sensitive to the upper part of the LFO cycle, the other to the lower part. If you don't want the LED's to also be sensitive to the Width control you can hook them up from the output of the LFO at point L15 on the PCB layout instead of hooking them off the Range pot, this way they will flash at constant brightness irrespective of the Width pot's setting.
BTW, when using current limiting resistors with LEDs, it doesn't matter what order the resistor and LED are in, as long as there is a resistor.
Quote from: doc_drop on February 08, 2010, 09:14:21 AM
O.K. I now have extra bright blue and green LEDs flashing alternately. It is one of the sexiest things I ever saw!
Quote from: sundgist on February 08, 2010, 08:55:47 PM
I find it funny that we have people here painstakingly biasing their fuzzes just right, finding new ways to get 'that' sound, filling boxes with rare mojo components, and I'm over the moon with a pair of flashing lights :icon_biggrin:
Quote from: mth5044 on June 11, 2010, 10:25:37 PM
Haha, because I thought you drew two penises, I will try to help you. 9v goes to the anode, which you drew, but you have Ra in the wrong position. Ra should be between the LED and lug 3. Then you have Rb, which looks good, but that connects to the anode of the second LED, where you have it to the cathode. Then switch the cathode to ground.
..I think
BTW, I would councel against hooking your penis(es) up to 9 volts without a suitably large current limiting resistor between it's anode and +ve. :icon_eek:
Holy crap! Next time I copy a layout I need to concentrate.
IT WORKS!!!
Quote from: frequencycentral on June 12, 2010, 10:06:46 AM
Quote from: mth5044 on June 11, 2010, 10:25:37 PM
Haha, because I thought you drew two penises, I will try to help you. 9v goes to the anode, which you drew, but you have Ra in the wrong position. Ra should be between the LED and lug 3. Then you have Rb, which looks good, but that connects to the anode of the second LED, where you have it to the cathode. Then switch the cathode to ground.
..I think
BTW, I would councel against hooking your penis(es) up to 9 volts without a suitably large current limiting resistor between it's anode and +ve. :icon_eek:
While I'd imagine this came from personal experience, I wouldn't believe it without pics (of your two penis) and how do you find out which end is the anode ???
..Guess I'm off to make a penis library for eagle.
Quote from: mth5044 on June 12, 2010, 10:39:38 AM
Quote from: frequencycentral on June 12, 2010, 10:06:46 AM
Quote from: mth5044 on June 11, 2010, 10:25:37 PM
Haha, because I thought you drew two penises, I will try to help you. 9v goes to the anode, which you drew, but you have Ra in the wrong position. Ra should be between the LED and lug 3. Then you have Rb, which looks good, but that connects to the anode of the second LED, where you have it to the cathode. Then switch the cathode to ground.
..I think
BTW, I would councel against hooking your penis(es) up to 9 volts without a suitably large current limiting resistor between it's anode and +ve. :icon_eek:
While I'd imagine this came from personal experience, I wouldn't believe it without pics (of your two penis) and how do you find out which end is the anode ???
..Guess I'm off to make a penis library for eagle.
Ah, it's a sorry tale. It started off as a lighthearted prank to take some of the on-stage attention away from my lead singer. But as time went by I found I needed more voltage to achieve the same effect. I started using two 9 volt batteries in series. Pretty soon even that wasn't enough and I was looking at back to back transformers and switched mode power supplies. Now, many years later, I am burnt out, the only thing that really turns me on is a Tesla coils in high heels.
Quote from: tuckster on June 12, 2010, 10:35:33 AM
Holy crap! Next time I copy a layout I need to concentrate.
IT WORKS!!!
Great! Pics and soundclips please!
Pic (http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg711143#msg711143)
Sound --> I have yet to record something. But I wait until I put in the correct speed pot 1M is too much.
Keto: my girlfriend asked me yesterday "penis?" as she saw your drawing.. veeeery funny :D
This is my version. It's very easy:
(http://forum.musikding.de/cpg/albums/userpics/24316/rate_shape_led3.JPG)(http://forum.musikding.de/cpg/albums/userpics/24316/normal_rate_shape_led2.JPG)
Thanks Tuck, I think that mirrors the 2nd drawing I did but anyways I'll refer to your example. Should have it finished up today, will try and get time to youtube it.
Mine ended up looking like this:
(http://img.photobucket.com/albums/v374/keto/Pedal%20Builds/PhaserLEDdetail.jpg)
Guts, could stand a little tidying at some point:
(http://img.photobucket.com/albums/v374/keto/Pedal%20Builds/PhaserGuts.jpg)
For the external, I'm sorry but you're going to have to watch the youtube video ;D 7minutes and change, all features explored.
http://www.youtube.com/watch?v=eqjmauZ7Dao (http://www.youtube.com/watch?v=eqjmauZ7Dao)
^^^
Really good video demo! I'd love to see you do another demo with a distortion before the phaser. Seeing the flashing LEDs makes me really want to add them to mine too...... :o
keto,
excellent job on that youtube demo ! .... i like your wiring job, also .... looks pretty neat to me ....
(i see that you used a trimpot for R12 .... good idea :icon_idea: )
Yeah Kudos on the LEDs :icon_mrgreen:
I better finish my boxes that use LEDs for eyes soon or else people WILL think I am copying you and Dead Astronaut...
The demo is first rate !!!!!,now I know what it will do and that I have to build one !!
Maybe I can trade some Ge transistors for the ICs I dont have ? Anyone interested ? PM me (I'm in AZ USA)
I need the 084 and the 13700
keto: it looks good!
I'm going to solder the LEDs to the 3PDT because I always think the phaser is on just because of the aditional LEDs that are always on.
Up to my armpits in phasers, so I hadn't bothered to check in on this thread in a long time. It was a lazy Saturday so I figured I'd etch me a couple of boards. One of the spare pieces of copper board accommodated a pair of Causality4 MkII boards perfectly, so I figured what the heck, etch 'em. Next obvious step was to check in here and see if there were any changes, samples, suggestions, mods.
Having listened to the samples submitted, and Keto's excellent video demo (cute graphics), this baby has moved way up the list. The additional controls make this a really fun little toy.
On top of a vibrato (dry-lift) switch, and wet level, one of the things I'm pondering is adding a little daughterboard with 2 extra fixed stages (one lag, and one lead), a unity-gain inverting stage, and mixer/output stage. The intent is to provide a sum and difference output for stereo, but use the additional stages to stagger where the phase-shift maxima is/are so that the sum and difference outputs don't cancel out in air. Normally, if you have matched sum and difference outputs, and feed them to separate amps, the effect effectively cancels out acoustically. The intent here is to make it a more robust "stereo" by making the sum and difference a little more dissimilar.
I was pondering a phasefilter switch, but thought better of it when I realized that it required using up the two swept stages, leaving only two fixed stages. I suppose if someone wanted to make a modulated lowpass filter, and skip the swept notch, it would be worth doing; particularly when one considers what the variable shape and range controls permit in the way of sonic options. We`ll see. I have some chassis with holes drilled in them already for other projects. If a spare hole persuades me, I`ll do it.
For now, thanks to Rick for doing this, and thanks to the others for their ideas, and persuasive soundclips.
I had asked elsewhere about how to add a wet mix knob, but not had a reply. It's definitely still over my head. It could stand to be a touch wetter for use with distortion. The vid I did over emphasizes the phase sound, relative to what I hear in the room. It's a while since I did that, but I think I was estimating around 60% wet as-is, and my desire to have the ability to take it as high as possible.
I recently reduced the value of R7 to 1k in mine. Increasing the timing cap C4 to 47uF got me really slow speeds but at the expense of faster speeds, reducing R7 sorts this out nicely.
R13 and R14 mix the wet and dry signal, reducing R14 or increasing R13 should give a wetter mix.
Now Mr Hammer is onboard expect major revisions................... :icon_biggrin:
As noted, the ratio of R13 and R14 sets the dry/wet balance.
Personally, I have never really found a use for mixes that were more wet than dry, so I tend to stick with a complete dry lift (via toggle), and variable wet mix, rather than a wet/dry balance pot. YMMV.
That being said, the balance of wet and dry to achieve maximum cancellation is a function of the actual amplitudes of each at the mixing node, NOT the numbers on the schematic. All these parts have tolerances, remember. So, it pays to have the capacity to zero in on maximum cancellation by including a theoretical too-much-wet setting.
So, being able to adjust wet level for subtlety AND optimum cancellation, might incorporate replacing a 27k mixing resistor with a 22k resistor and 100k pot wired as variable resistor. This will let you go from more wet than dry (which may well be flawless 50/50 mix in actuality, given tolerances), to around an 80/20 (dry/wet) mix for just a touch of animation in the background. Worst case scenario is that with the wet dialed up full, putting it into vibrato mode (dry cancellation) results is a little bit of boost.
Finally, for the adventurous, there is always the option to use envelope control of speed. Simplest thing is to use the output of the op-amp input buffer stage to feed something like a Dr Q/Quack rectifier, and use that to drive an optoisolator, with the LDR placed in parallel with the speed pot. Play harder, or turn the envelope sensitivity up, and the speed increases as you dig in. Naturally, with the LDR placed in parallel with the stock 470k speed control, turning the speed up manually would imply less impact of the LDR.
Okay! Finally finished wiring and firing it up, and this is a neat little gadget. I built mine with an LM324 and LM1458 for the quad and dual op-amps, simply because they were handy, and used a 50k Regen pot (instead of 10k) to be able to dial in more shimmery sounds. Works just fine.
Didn't fire up properly at first because I failed to pay proper attention to ALL the cues for chip orientation, and was misdirected by the U1 and U2 legend being the same orientation in the picture (and no notch indication!). It may well have been brought to our attention in this thread, but at damn near 240 posts, I wasn't about to read them all, and simply worked from the drawings alone. Measuring what I thought was V+, and I got readings below 1Vdc with a fresh battery, so I took a look at the datasheet for the 324 and realized I had installed the chip the wrong way around. Desoldered and resoldered it back in properly, and it fired up right away. Watch out for those square pads, kids!!
The Range control is almost worth putting in a foot-pedal. I find that setting the speed and Shape just right, one can play with the Range pot and get quasi S&H filter sounds. I look forward to dickering with the allpass/lowpass thing and seeing if that provides a more pronounced S&H sound. The first one, though, will remain plain vanilla, with the exception of an always-direct out jack and a switch for selecting pure wet, a 66/33 mix of dry/wet, and a 50/50 mix for the main output jack. That'll let me run it in "stereo", without having to implement any fancy sort of bypass switching. With the 2nd jack always clean, bypass only has to be implemented for the effect output. The next build after that will have some other frills, like an additional 2 stages, sum/difference, and envelope control of the speed.
The usability of the Shape control is partly a function of the Range and Width controls. That is, extreme Shape settings (ramp or sawtooth) tend to produce undesirable thumps when the Range is set too low and the Width is too strong.
At max Regen, I'm getting oscillation, so I think I'll either a) put a 470R resistor in series with the pot, b) replace the 10k fixed resistor with an 11k, or c) measure the existing resistor and see if I can find one that is at the higher end of the 5% tolerance. One of those oughta work.
Again, many thanks to Mr. Central for this. Now that I managed to score a pair of 4526 chips to complete my E&MM Harmony Generator, I'm looking forward to some interesting sounds this autumn.
We have a government-wide United Way charity drive every autumn, and in past I've contributed pedals to a silent auction to raise money. A chorus pedal last year raised $100. I think this year's will be the Causality IV.
That's great Mark. So can we look forward to some Hammer mods? :icon_biggrin:
Hi frequencycentral,
I'm thrilling waiting for mine. I'll post pics and and comments (if you don't).
A+!
Quote from: frequencycentral on February 08, 2010, 06:26:14 PM
Here's the artwork for the 5 knob MkII PCB, it includes pads for the addition of an extra stages daughter board - more on this some other time! The 3 knob MkI version can also be built using this layout.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIPCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIPnP.gif)
how big is this Board?
It fits nicely into a 125-C type box. Maybe someone else can chime in about 1590B style.
Each "step" (the minimum distance between two terminals) should be about 1/10 inch (2,54mm).
So you can count them and do the math to see how big is the board ;)
Another C4 MkII. I built this one for tubelectron. It features a new layout with a few value tweaks and provision for a trimmer to set the output level, PCB from guitarpcb.com (http://www.guitarpcb.com/) and waxing/waning LEDs situated in the hull of NCC-1701.
(http://i210.photobucket.com/albums/bb292/frequencycentral/C41.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/C42.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/C43.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/C44.jpg)
Cool how you have the LED's arranged as portholes of the Enterprise-A, etc. :icon_cool:
Some defined values for the pots would be nice. Speed, Shape, Range, Width, and Regeneration.
Look killer. Might be my next endeavor. Thanks again Rick. :icon_biggrin:
Hi Rick,
Now I am in my garden waiting for your UFO's Causality 4 MkII phaser arrival... By night, of course... I won't be mistaken, I think...
A question : there is no battery clip installed inside = it would draw too much current from a 9VDC batt ?
A+!
Ok cool! So Mark Hammer has implemented extra stages to his Causality: http://www.diystompboxes.com/smfforum/index.php?topic=87166.msg733708#msg733708 (http://www.diystompboxes.com/smfforum/index.php?topic=87166.msg733708#msg733708)
Once again, I find myself without a Causality, having sold my MkII, and built another MkII for Bruno. So it'll soon be time for me to build another for myself. Several possibilities present themselves with my next build (I might as well try something different!):
- Extra stages, ie a second LM13700 implemented as Mark did his.
- A seperate Range pot for the extra stages - two sets of notches, one 'bright', the other 'dark'. Or.....
- Extra (modulated) stages with a seperate Range pot using the 'wet only' pads as send and return, or in parallel with the existing modulated stages. The intention being to achieve parallel phasing with two sets of notches, one 'bright', the other 'dark'.
- Some additional (switched) fixed stages using the 'wet only' pads as send and return. The fixed stages having four different cap values. The intention being an attempt at through-zero-phasing by delaying the dry signal with respect to the wet (modulated) signal.
All highly speculative I know, but I'm gonna try it all. The more I think on it, the less likely it is that I'll build a stock PCB and try some mods. I'll breadboard the whole thing again and try everything, probabaly do a new layout incorporating whatever works well. Any other ideas I should try? This may be a couple of months away......
Rick, I´ve been following this thread, will build one eventually.
Regarding new features, I always thought that the usual triangle / whatever wave for modulating was quite boring, so, why not make a more interesting LFO? Sequenced a la seek wah, two parallell LFO´s, another LFO modulating the main LFO, envelope controlled LFO speed or depth, etc etc... just my personal ideas.
Great work!
Quote from: Morocotopo on October 04, 2010, 02:51:55 PM
Rick, I´ve been following this thread, will build one eventually.
Regarding new features, I always thought that the usual triangle / whatever wave for modulating was quite boring, so, why not make a more interesting LFO? Sequenced a la seek wah, two parallell LFO´s, another LFO modulating the main LFO, envelope controlled LFO speed or depth, etc etc... just my personal ideas.
Great work!
Hi Morocotopo,
Your idea is good - I have tried one which is probably similar in the sounding result : 2 phasers paralleled with different rates. I discovered that it was the way was obtained the miraculous viola/violin tones on my old Crumar Multiman I , and certainly on Elkas too.
A+!
(http://i210.photobucket.com/albums/bb292/frequencycentral/C4DaughterPCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/C4DaughterPnP.gif)
Quote from: tubelectron on October 04, 2010, 04:07:00 PM
Quote from: Morocotopo on October 04, 2010, 02:51:55 PM
Rick, I´ve been following this thread, will build one eventually.
Regarding new features, I always thought that the usual triangle / whatever wave for modulating was quite boring, so, why not make a more interesting LFO? Sequenced a la seek wah, two parallell LFO´s, another LFO modulating the main LFO, envelope controlled LFO speed or depth, etc etc... just my personal ideas.
Great work!
Hi Morocotopo,
Your idea is good - I have tried one which is probably similar in the sounding result : 2 phasers paralleled with different rates. I discovered that it was the way was obtained the miraculous viola/violin tones on my old Crumar Multiman I , and certainly on Elkas too.
A+!
Having as many phasers as I do (not bragging, just an admission of a sickness!), I can vouch for the pleasing quality of applications which feel less periodic or cyclical in nature. There are several ways to achieve this.
1) One phase-shift path, modulated by one master source, derived from mixed sources. Those could be more than one LFO, or random+LFO. One my Boss RPH-10, I modded it to have envelope following mixed in with LFO modulation, so you can "push" the effective sweep range higher (or lower) by playing harder.
2) One phase-shift path, but separate chunks of it (in series) modulated by separate independent sources.
3) Several parallel phase shift paths, each separately modulated, but arriving at the same common mixing stage with the clean signal.
4) Several clean+allpass sections, run in parallel.
5) Several clean+allpass sections (i.e., complete phasers), run in series.
And, departing from the normal, briefly.....
6) A series of phase-shift stages modulated by source A, and additional stages in the feedback loop, modulated by source B.
Of course, all of this is multiplied by the assorted waveform variations. Let's say we have a 4-stage/step analog sequencer providing 4 continuously adjustable repeating CVs. That gets set to a slow speed, with no glide, just a pure stairstep, and gets mixed in with a "normal" triangular or similar LFO waveform, set for modest sweep width. That combination should get you a normal-sounding sweep that keeps shifting ranges. Of course, set the sequencer for faster speed, and the LFO for medium speed, and you'll end up with something approximating a quasi-random S&H sound.
Or you can get ALLweird, and build one or more of John Blacet's DPG units, that were originally devised to sweep the Blacet Phase-filter.
http://www.blacet.com/dpg1.jpg
http://www.blacet.com/dpg2.jpg
I have always wanted to build the DPG. I bought enough parts for two about ten years ago. I started one and got it about half way. At the time my skills were not that great, so I stopped, thinking I would get back to it in the future.
Hi All,
Will a NE5517AN work in place of the LM13700? It is supposed to be a direct replacement. I am just getting the parts together for this for a friend.
Hey Rick, did you consider this:
Casuality may be a misspelling of:
* Casualty, a person who is killed or injured in a war or disaster
* Causality, the relationship between cause and effect
* Casual, the characteristic of being informal
Hate to be nit picky but.... ::)
But it is number 2, isn't it? Causality.
I've seen at least one built as a "Casualty" though.
Yeah, it's always been Causality (http://en.wikipedia.org/wiki/Causality) to me. ;) It seemed to make sense at the time, phase shift being the cause, phasing being the effect. And 4 because there are four stages of cause, the effect being cumulative. But I am aware of some folks who think/thought that it's Casualty. Why would anyone call a phaser Casualty? Ok, I guess a non working build would be a casualty. I'm currently laying down plans for my Causality Modular (http://circuitworkshop.com/forum/index.php?topic=184.msg4778#msg4778)..............
That what I love about you Rick you even invent new words. I just ran through the thread trying to nail down the 5 pot values. Where do I look? ???
Thank you all,
Chris
Quote from: Pigyboy on October 13, 2010, 04:35:07 PM
That what I love about you Rick you even invent new words. I just ran through the thread trying to nail down the 5 pot values. Where do I look? ???
Thank you all,
Chris
The MkII schematic with all the pot values can be found on page 6: http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg680532#msg680532 (http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg680532#msg680532)
Thank you Rick
Rick,
Reading over the thread and seeing that there is a "unity" issue. Can a 100K linear pot be added to the build in place of R12 to manually adjust the output volume level? Could this be a 6-knob Causality?
Quote from: Govmnt_Lacky on October 14, 2010, 10:26:42 AM
Rick,
Reading over the thread and seeing that there is a "unity" issue. Can a 100K linear pot be added to the build in place of R12 to manually adjust the output volume level? Could this be a 6-knob Causality?
Yes you can do that I guess. But it's probably better to just use a trimmer instead. I can't see the value in having a volume knob on a phaser. I did a layout including space for a trimmer, if you look at the gut shot of my last build a couple of pages back you'll see the trimmer. I'll post that layout a little later.
Quote from: frequencycentral on October 14, 2010, 12:29:48 PM
Yes you can do that I guess. But it's probably better to just use a trimmer instead. I can't see the value in having a volume knob on a phaser. I did a layout including space for a trimmer, if you look at the gut shot of my last build a couple of pages back you'll see the trimmer. I'll post that layout a little later.
Hey Rick,
I looked over the layout you have on Page 7. I see that R12 is installed however I do not see a spot for a trimmer. Is this the latest layout that is on this thread now? If not, then your offer to post the trimmer version of the PCB layout would be much appreciated!
Thanks as always ;D
The Retro-Sonic phaser ( http://www.tonefactor.com/prodimages/retrophaser.jpg ) includes a level control. It allows for adjustment from somewhat lower than bypass (for those who wish to engage the phaser for rhythm sections) to somewhat higher than bypass (for those who wish to use the phaser for solos), without going full off. I did the same thing for one of my Ropez pedals, and it can be useful, though obviously not to everyone.
Here's the latest layout, just the addition of the blue pads for a trimmer instead of R12. I spaced it for the specfic size of trimmer I usually use. I'm also working on a layout for a Causality 6, with 4 OTA stages instead of 2, and following Mark Hammer's advice for implementation of the extra stages. I'll try to include pads for a few different trimmer sizes in that layout.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIV2PCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkIIV2PnP.gif)
Thanks Rick. Cannot wait to get this one on a PCB!
One last question about the Speed pot. As per the layout, I know that Lug 2 is on the right. Which lug is connected to the left pad? Lug 1 or Lug 3 for proper Speed control?
Thanks a ton! 8)
Speed lugs are 2 and 3. Just leave lug 1 with no connection, or connect it to lug 2.
Based on Mark Hammer's addition of 2 extra stages to his build, I've made a new layout for
"Causality 6" - as yet unverified, and it could do with a set of sharp eyes to check it for errors....... :icon_biggrin:
Features:
- 2 extra OTA stages that can (optionally) be switched in or out via a DPDT.
- Provision to add even more stages.
- Pads for wet only mod.
- Optional odd/even stages in the regen path (parity switch).
- Input section options (R38, C12/R37)
- Polarity protection (D3).
- Pads to fit pretty much any size trimmer in the VR1 position.
This is a little speculative. I'm assuming the extra stages will work as shown, and that the parity mod will do also. My experience tells me that it will. I'm planning to use two of these PCBs for my super-duper-semi-modular Causality when I eventually get around to it.
The original
Causality 4 board was 20 x 22 pads, the
Causality 6 is 21 x 25 pads, just a bit bigger - nice job Rick!. It should still fit in a 1590B, though a 1590BB build will be easier, especially if all the options are incorporated.
As is customary, I am happy to receive any PCBs that folks might want to send my way! ;D
(http://dl.dropbox.com/u/967492/C6%20PCB.gif)
(http://dl.dropbox.com/u/967492/C6%20PnP.gif)
First you always make me laugh. Second, don't get hurt patting yourself on the back. And, I am just getting ready to make boards for the 4 so I will try to get a transfer of the 6 and make it with the others. I will let you build the 6 while I hurdle the 4.
"Dammit Jim, I am not a miracle worker!" ::)
For what you add VR1? What is purpose of it? ???
Sorry for my bad english ::)
Quote from: Xide88 on October 19, 2010, 01:01:31 PM
For what you add VR1? What is purpose of it? ???
Sorry for my bad english ::)
So you don't have to trust what
my idea of unity gain is, you can fine tune it yourself. Or....
Quote from: Mark Hammer on October 14, 2010, 12:49:48 PM
The Retro-Sonic phaser ( http://www.tonefactor.com/prodimages/retrophaser.jpg ) includes a level control. It allows for adjustment from somewhat lower than bypass (for those who wish to engage the phaser for rhythm sections) to somewhat higher than bypass (for those who wish to use the phaser for solos), without going full off. I did the same thing for one of my Ropez pedals, and it can be useful, though obviously not to everyone.
....so you could instead rig it up as a panel mounted control, if that's your bag.
Absolutely. Of course, panel space is always precious, so think through whether it is a needed feature first.
Quote from: Pigyboy on October 13, 2010, 10:06:53 AM
Will a NE5517AN work in place of the LM13700? It is supposed to be a direct replacement.
+1. I ran it through DatasheetArchive and the ONLY comparable cross referenced part for the LM13600 or LM13700 is the NE5517AN. Can anyone confirm a build with this chip?
I got 5517's when I ordered either LM 13600 or 13700 (forgot which one) and it worked fine for me.
Maarten
Here is my proposed implementation of the features for the Causality 6 PCB posted on page 13 of this thread:
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality6PhaserRev2.jpg)
It's a big schematic, with a lot going on, so here's a direct link which is bigger:
http://dl.dropbox.com/u/967492/Causality%206%20Phaser%20Rev%202.JPG
There are a few features which *I think* will work out well, but I wanted to discuss them before diving in.
- Regen odd/even switch replaced by a 47k pot. The idea is that odd stages regen path will be available CCW, even stages regen path will be available CW, no regen will be available with the pot at 12 o'clock. I know this implementation works because I tried similar while breadboarding my Sonic Death Ray phaser.
- Phaser/Filter implementation on the 3rd and 4th OTA stages. C1 and C2 will be mounted on the filter/phaser DPDT
- Wet Only switch replaced by a Dry Cut pot
So.......the 1st and 2nd OTA stages can be switched out. And the 3rd and 4th stages can be switched to filter mode. Which means the unit can function as ONLY a lowpass 12dB/Oct filter if desired, with no phasing. Cool! Now, Mark Hammer said this about phaser/filter mods a few pages back:
Quote from: Mark Hammer on February 25, 2010, 02:52:37 PM
It really comes alive, however, when the clean signal is lifted and all you have is the combination of allpass and lowpass. Under those conditions, what you get is a bizarre mélange of what sounds like vibrato, tremolo, and autowah at the same time. The vibrato, arising from allpass-only, makes sense. The LFO modulated lowpass sounding like an autowah also makes sense. And because of the way in which filtering out the treble results in shifts in apparent loudness, it sounds a bit like tremolo. The overall package is best described as sounding "swampy" and syrupy. It oozes mojo if your LFO has the right properties.
That's great!
Now, as the 1st and 2nd OTA (phasing) stages can be switched out, and the 3rd and 4th stages can be switched to filter mode, and the unit can function as ONLY a lowpass 12dB/Oct filter........here comes the BIG question........
- In 'filter only' mode there are still 2 fixed phase shift stages in the 'wet' signal path. As each fixed phase shift stage shift the phase by 90o, the two fixed phase shift stages will shift the phase by 180o - the equivalent of an inverter (Yes?). Now, if you take a lowpass filter and mix it with an inverted dry signal in the correct amount, you get a highpass filter, courtesy of phase cancellation. So I am making the assumtion that the two fixed phase shift stages are equivalent to inverting the signal with respect to the dry signal.........so.........using the Dry Cut pot, you will be able to dial in either lowpass (by cutting the dry signal), or highpass (by mixing in the dry signal in the correct amount).
I'm making a major assumption here, that the two fixed phase shift stages are equivalent to inverting the signal with respect to the dry signal. I would really appreciate some feedback on this!
The impact of the 2 fixed stages will depend on the RC value. Remember that each stage contributes up to 90 degrees of shift, but contributes less than that for frequencies below some inflection point.
So, if we have a fixed stage with a .047uf cap to the non-inverting pin, and a 10k resistor to ground, the full 90-degree-per-stage shift doesn't really kick in until around 340hz. If you wanted that 90 degrees to apply across the entire range, you'd probably want to either increase the cap to maybe .22-.47uf, or increase the resistor to ground to 100k or so.
Hi All & Rick "frequencycentral",
Sorry to be so late to contribute for review of the Causality 4 MkII phaser - custom-made by frequencycentral, with full UFO appointments :
(http://img11.hostingpics.net/pics/391921IMG_6708.jpg)
In front of my vintage phaser army (Morley PFA, MXR ph90 & Ph100, EH Small Stone, italian Silversound SuperPhaser), how does sound the Causality 4 MkII phaser ?
Of course, samples would be useful, but I am not sheduled to do that yet, unfortunately.
- in normal phasing situations, the N°1 remains the Phase 90, unrivalled in smooth and lush, then the Phase 100, and the others comes after.
- in sharp phasing situations, the Small Stone and the Silversound are on one side : regular and wide sweep; the Morley and the Causality 4 MkII are on the other : dramatic extroverts.
- in odd/unusual phasing situations, the N°1 ex-aequo are the Morley PFA and the Causality 4 MkII - and let me say that rivalling the PFA is not an easy task (listen to the intro of Kool & The Gang's "Ladie's night" 1979 hit for the deep/dramatic PFA sound).
To sum up, the Causality 4 MkII phaser is not best at smooth, liquid and lush phasing, but think of a sharp, cutting, unusual sounding phaser. A device which would have been built by EH in it's vintage years, if it hadn't some issues :
1 - When the regen control approaches the max (3/4), it saturates and the rate is somewhat "wobbled".
2 - Sometimes there is "clicks" at the rate of the LFO, like if it's wave was clipped.
3 - The spead of the speed control isn't progressive (it may only be a matter of pot tap) : all the fast speeds are at the end.
4 - there is some interaction between the speed, range and width controls : lowering the speed narrows the width and somewhat displaces the range.
My Guitar is a 1980 stock ES-335, and the amp is a '75 Twin-Reverb. The PSU is a new 9VDC EH wall-wart (the one sold with the Holy Grail Nano reverb), so nothing special.
Since I think that point 3 can be improved, the real annoying issues are 1 and 2.
Rick : do you know how to get rid of these 2 problems ?
A+!
Hi
Obviously im not Rick, but I bought his phaser C4 in the other forum
beginning with the f...... . Whereas I totally agree with your points 1 to 4
I was rather relieved that it didn't "swoosh" like a smallstone,
because this way you almost sometimes forget that it is altering
every note until you play several times the same note. I personally
however found the P90, well ..boring after 10 minutes,but I dig the
RedWhichAnalog MoonPhaser but this one has up to 6 stages Iirc.
(My main guitar is a Benford(kind of big apple strat with a Laney LC15)
Thanks,Rick ,for this unique project!
Regards Jean-Marie
I got the '4 working using the pnp from page 3. Thank you Rick. I need to read thru the thread again as it seems the regen & speed pots only work at the ends of the dial. Abd it sounds like it is clipping a bit at certain settings. Hard to tell much out of a box though.
Chris
Thank you Rick for designing a phaser that is not overly complicated to build and sounds great! It is currently on my breadboard as I try out the MKII mods.
I noticed on your MKI prototype you added 2 switches for depth and wave shape. Are these comparable to the width and shape pots on the MKII? I like the idea of a ramp up/triangle/ramp down switch instead of a pot. I imagine it would be a SPDT center-off switch, but I am not quite sure how to wire it. Could someone please tell me how it would be implemented? What about the depth switch?
Quote from: Pakaloabob on November 13, 2010, 03:00:19 PM
Thank you Rick for designing a phaser that is not overly complicated to build and sounds great! It is currently on my breadboard as I try out the MKII mods.
I noticed on your MKI prototype you added 2 switches for depth and wave shape. Are these comparable to the width and shape pots on the MKII? I like the idea of a ramp up/triangle/ramp down switch instead of a pot. I imagine it would be a SPDT center-off switch, but I am not quite sure how to wire it. Could someone please tell me how it would be implemented? What about the depth switch?
Thanks! Glad you like it.
Just replace the Shape pot with an on-off-on switch. The downside is that the saws are then faster than the triangle.
For the depth switch I did something like this: http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg670900#msg670900
Quote from: tubelectron on November 03, 2010, 05:51:29 AM
1 - When the regen control approaches the max (3/4), it saturates and the rate is somewhat "wobbled".
2 - Sometimes there is "clicks" at the rate of the LFO, like if it's wave was clipped.
Rick : do you know how to get rid of these 2 problems ?
A+!
I'll work on it! I'm currently building a couple of Causality 6, so I'll experiment a bit.
I didn't realize using a switch instead of a pot for the shape would cause different speeds between the modes. I guess I'll stick with the pot.
As for the depth switch, I did see the post about changing R5 to get a wider LFO sweep but you also said that it would slow the LFO speeds and cause asymmetry. In the MKII it looks like you have chosen to vary the resistance between pins 6 and 7 of the dual opamp instead. Did you find this method of varying width also changes the speed and symmetry?
I wanted to report some funny behavior I noticed with my C4 phaser build.
I built the perfboard following the markII layout, but left out the shape and width pots. There was a noticeable ramping up on my build. I double checked all my solders and traces. Everything seemed fine. I then checked voltages and noticed that my Vref was fluctuating. I noticed that R33 was the only connection between the LFO and Vref. When I removed the resistor, Vref stabilized and the ramping disappeared.
After I did this I re-read this entire thread and saw that Rick did mention the fluctuating Vref, but I don't think there has been any further talk about it. However, there was this:
Quote from: frequencycentral on May 04, 2010, 01:01:57 PM
Other mods I made to my MkII:
- R5 = 220k
- C4 = 47uF (I just paralleled a 33uF with the existing 10uF)
- R33 = 47k
Does the R33 substitution stabilize Vref?
Since I am not using the shape pot, is it still possible to use the width pot effectively? Do I need to have the resistor tied to Vref?
Damndest thing. Last weekend I built a C6 using the layout on page 13. When I fired it up I just got clean sound - no phasing. On inspection, the vref was really low, like just above 1 volt, and both 13700 were getting hot. I checked for shorts and incorrect component values. Nothing. I triple checked the layout against the schematic and previous layouts. Nothing. So I decided to start populating another PCB, checking the vref after soldering each part. Turns out that after inserting the resistors to ground from pins 8 and 9 of the 13700 with the 220k/220k voltage divider I've previously used for vref, it didn't want to play nice. So I removed the 220k/220k voltage divider and broke it out onto breadboard. It worked with a 10k/10k voltage divider. What's really got me foxed is that I only populated one 13700 and it's resistors, so it's not the fact that this is a '6' and not a '4'. And this is the fourth Causality I've built, all three of the others used either 220k/220k or 100k/100k voltage dividers for vref without a problem. I fixed my non-functional build by using a 10k/10k divider, but I just can't figure out why it didn't work with the normal values I use. Confused of UK.
Anyway, the 2 extra swept stages are really cool, adds another dimension. I didn't add the regen parity switch to this build, but I'll try it on the PCB I just half populated. I'm also gonna cludge in a 78L05 for with a 1N4148 vref instead of the resistor voltage divider. This will sort out the problem of the vref fluctuating reported in the above post too.
Hi Rick,
Would it be related with my C4MkII issue :
QuoteQuote from: tubelectron on November 03, 2010, 03:51:29 AM
1 - When the regen control approaches the max (3/4), it saturates and the rate is somewhat "wobbled".
2 - Sometimes there is "clicks" at the rate of the LFO, like if it's wave was clipped.
Rick : do you know how to get rid of these 2 problems ?
A+!
I'll work on it! I'm currently building a couple of Causality 6, so I'll experiment a bit
Or have you find a solution to it ?
Thanks !
I've got a second C6 board half populated. I'm gonna just populate the audio section and hook it up to a breadboarded LFO. I'm convinced that the LFO part can be improved to smooth out the irregularities. I'm also gonna try the lowpass/highpass filter mods mentioned above. Happy new year!
really digging this project!
Which D1 and D2 i should use? 1n914??
Quote from: Xide88 on February 26, 2011, 05:50:15 PM
Which D1 and D2 i should use? 1n914??
Yup, that'd work. I use 1n4148. I haven't ironed out the bugs in the C6 design yet, won't get to it for another month maybe, so until then I'd recommend people stick to C4.
Thanks a lot Rick!!! :)
But i have another question(
Where are connections for Width lug 3 and Regen lug 1?
It seems in the schematics that lugs 1 & 2 for Width and lugs 1 & 2 for Regen are soldered together ???
Or i make a mistake and there are simple n/c to these lugs?? ???
Quote from: Xide88 on February 27, 2011, 02:43:32 AM
Thanks a lot Rick!!! :)
But i have another question(
Where are connections for Width lug 3 and Regen lug 1?
It seems in the schematics that lugs 1 & 2 for Width and lugs 1 & 2 for Regen are soldered together ???
Or i make a mistake and there are simple n/c to these lugs?? ???
Either. Solder the unused lugs to lug 2, or n/c. It's all the same.
Just built it and it doesn't working right :(
1) It is phasing only at high values of speed. with almost all values of range and all another at 0
2) other pots are working, but speed must be high for phasing, almost maximum
3) with all pots maximum or speed, width, shape at maximum i can hear a thumping sound, i hear that LFO is working, but only at speed almost maximal,
but if i try i can hear that lfo is working even at minimum of speed, but it isn't phasing :'(
i check all voltages and they are almost similar to Rick voltages!
Where is the problem? ???
I use TL072 instead of NE5532, сan it be a problem?
bump :-[
As the opamp is different that *may be* the issue. I never tried a TL072. Though I would imagine there shouldn't be too much difference. I don't have a Causality here at the moment, so I can't try a TL072. But it's of course possible there could be an error in your build?
I will try make it again and try to find NE5532 :)
Rick, any news about Causality 6 or it's PCB is verified? :)
I'm in the middle of a big build (http://dl.dropbox.com/u/967492/TM02.jpg) at the moment, as well as some client builds, as soon as I'm done with them I'll be verifying C6 with all the features mentioned in this post (http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg740457#msg740457). So about a month.
Thanks a lot, Rick! :)
Hey there. i just finished up a build of this circuit with the 2 stage daughterboard and phasefilter mod. This is a beautiful sounding phaser, and i just wanted to say thanks for it. oh, i also used a modified version of the small clone LFO. i saw earlier in the thread that there were issues with the added stages, but it worked fine for me. could it be maybe the current draw of the ICs being used? i used UA741s for the audio op amps and a LF358 for the LFO and didn't have any issues, so i thought i may may throw that out there for anyone who might care.
Kris, that's great! Tell me about the filter mod - how did that work out? What cap values did you uses? Did you implement any type of switch hitter or inverter for lowpass/highpass. Would also be nice to see a schematic of the LFO you used. And generally a lot more info (and PHOTOS) of your build. Congrats an well done!
the filter mod worked out really well. just as Mr. Hammer has said numerous times it's somewhere between filter phase ands tremolo especially with the dry signal cut. i didn't think to look at seeing if switching between HP andLP was even an option. i will need to rehouse it at somepoint so maybe then. the box is pretty simple really since i knew there would need to be a rehousing in the future.
(http://a5.sphotos.ak.fbcdn.net/hphotos-ak-ash4/200567_1810363251748_1019998126_2051936_7091097_n.jpg)
here's the LFO. the mods basically made it a littler bit faster on the fastest end and the depth takes it from barely a warble to full on phasey goodness. i may have the pot lugs for the depth control backwards in the schematic, it's just set up as a variable resistor that goes to 0 ohms for max depth.
http://dl.dropbox.com/u/23916647/small%20clone%20lfo.png (http://dl.dropbox.com/u/23916647/small%20clone%20lfo.png)
i forgot to answer this. i used the .033 caps called for in the schematic. when i rehouse i will probably add the range control for even more versatility. as it is now in phase mode i get a really nice wowwowwow thing going on, similar to a roland jet phaser. haven't tried it with any dirt yet, but hopefully i will get to soon.
Ok, I'm just putting together the lastest iteration of Causality on a C6 PCB. I'm using this build as a test bed for a few things, based on this schematic:
http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg740457#msg740457
What I've done so far:
- Replaced the vref voltage divider with a 78L05 - it was bothering me that the vref fluctuated with the LFO - now it's rock solid.
- Implemented the 4/6 stage switch - really nice variations available here.
- Implemented the regen pot as a mix between odd and even stages of regen, null in the middle, odd one side, even the other side - works really well and again some nice variations are available.
- Implemented the phaser/filter switch - not really happy with this yet. I'm gonna try drastically reducing the filter stage cap values, as most OTA filters I'm aware of have their filter caps in the pF range - Oberheim SEM is 300pF, Korg MS20 is 1nF, Oscar is 1nF, Wasp is 1000pF.......
EDIT: I just realised, having scanned a few VCF schematics, that the filter mod should send the cap to vref, not ground........What I haven't done yet is work out how I'm gonna do the HP/LP thing. My gut tells me a switch hitter circuit will work here, as it's all about phase cancellation. I sure hope I can get it working how I want, as the HP/LP is already etched onto the enclosure....
Here's a couple of work-in-progress shots.......
(http://dl.dropbox.com/u/967492/CViPF%20top.jpg)
(http://dl.dropbox.com/u/967492/CviPFguts.jpg)
While it is certainly easiest to implement a phase-filter mod using the existing caps, by simply "flipping" one end of each cap to either ground (for lowpass) or the input (for allpass), you may not necessarily like where the lowpass range is set to.
In such instances, it may be preferred to have two caps with one end connected to pins 5/7 or 10/12, and connect the one value when using that stage as an allpass section, and the other when using it as a lowpass section.
Again, that isn't a necessary addition, just a means to nudge the lowpass frequency range over to where you might feel you prefer it.
Of course, for those who like to have too many switches, there is also the option of being able to select different caps for the lowpass range. :icon_rolleyes: :icon_mrgreen:
Yes Mark, I think I'll go with the switched caps idea you mentioned. I've run out of playtime today so I'll get onto that tomorrow.
Incidentally, do check out some vintage synth OTA filters - the filter cap always goes to ground - but of course synths use bipolar supplies, so it needs to be vref in pedals. Mine's working much better now I've used vref.
The other unexpected feature I just found is a wide range of new sounds are available in phaser/filter mode because of the way I've got the regen hooked up - still getting my head around what's actually happening, but I like it. Of course, I can also switch out the phase stages and just use the filter stages more variation. Nice to have options........
Hadn't checked in on this thread in a while. Nice evolution of the circuit. That's a clever trick you have with the regeneration being variable from inverting to noninverting.
I see you have the dry mix set to 50/50 when the dry mix pot is at max. Consider lowering the value of the dry-mix mixing resistor to 22k or even 18k, as a means to make the dry sound dominant (when you want) to render the phasing effect subtler. You still get the option to turn the dry level down to produce vibrato effects, but you now have the option for subtler effects when all you want is a little shimmer.
P.S.: Doesn't the absence of any cap in the regen path cause problems?
Quote from: Mark Hammer on April 17, 2011, 07:44:02 PM
I see you have the dry mix set to 50/50 when the dry mix pot is at max. Consider lowering the value of the dry-mix mixing resistor to 22k or even 18k, as a means to make the dry sound dominant (when you want) to render the phasing effect subtler. You still get the option to turn the dry level down to produce vibrato effects, but you now have the option for subtler effects when all you want is a little shimmer.
Better yet, sling the mix pot between the output of input buffer and the output of the last filter stage and you can blend between 100% dry to 100% vibrato, with any blend of phasing in between!
Do keep in mind that the output stage is an inverting op-amp. So, reciprocal adjustments to the input resistor for the wet or dry side also have implications for the gain of that stage.
Consider, with input resistances of 27k and a feedback resistance of 15k, the stage provides some attenuation. If the input resistance for either side dips below 15k, then the stage starts to add gain. And once you have gain implications, then you need to add an output volume pot to achieve the desired effect/bypass balance. That's the primary reason I suggested what I did; it just ends up getting you 90% of what you want but with much less nuisance than trying to get 100%.
Quote from: Mark Hammer on April 18, 2011, 09:55:28 AM
Do keep in mind that the output stage is an inverting op-amp.
Are we looking at the same schem? I see a non-inverting output stage: http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg740457#msg740457
Bah! You ARE correct. I was looking at the Ross Phaser, not the Causality output stage. :icon_redface: :icon_redface:
Carry on!
The phaser filter experiments continue. Even with very small filter cap values (1n), I'm still finding that the filter is doing it's thing way below where the phaser wants to play. So I've referenced the filter OTA's (stages 3 and 4) Iabc inputs to ground with a 10k resistor (to raise it's initial frequency) and referenced the phaser OTA's (stages 1 and 2) Iabc inputs to +ve with a 4k7 resistor(to lower it's initial frequency). Now it's just a matter of selecting the correct phaser cap values. As I've fkd about with stages 3 and 4 initial frequency I now have to raise the phaser caps values to get good phasing. Likewise, stages 1 and 2 having a lower initial frequency now need their cap values lowered. I've just installed sockets for the caps, so tomorrow I'll have myself a little cap frenzy. All this before I even think about highpass/lowpass.....
I have the pedals with a phase-filter setting, two Ross/Ropez pedals, and a Small Stone Clone. Two use the same cap values for lowpass as the allpass, and one uses a smaller cap value.
When the cap value is the same for lowpass and allpass, more of the mids and highs are attenuated, which has the effect of reducing the overall signal amplitude (when in wet-only), That's part of what gets the strange mélange of vibrato, tremolo, and modulated-wah. Of course, it also drops the "intelligibility" of the wet signal because all those mids and highs are gone. With a smaller cap value, more of the lower mids remain, which improves clarity but attenuates the tremolo-like modulation of overall amplitude.
Your choice. Neither is "better", just a different kind of sound.
Hi Rick,
You may remember this one :
(http://img11.hostingpics.net/pics/391921IMG_6708.jpg)
(http://img11.hostingpics.net/pics/930193IMG_6680.jpg)
and this :
QuoteQuote from: tubelectron on November 03, 2010, 03:51:29 AM
1 - When the regen control approaches the max (3/4), it saturates and the rate is somewhat "wobbled".
2 - Sometimes there is "clicks" at the rate of the LFO, like if it's wave was clipped.
Rick : do you know how to get rid of these 2 problems ?
A+!
I'll work on it! I'm currently building a couple of Causality 6, so I'll experiment a bit
About which I have no news from you...
Building pedal is good, but building them with no functioning issues is better...So, where is the problem and what are the mods I can do by myself on the circuit to get rid of thse issue, as above ?
No such problem occurs with my Phase90, my SmallStone 1978 or my PFA Morley.
Sorry to be insistant, Rick, but the pedal you've built for me isn't usable as is !
Thanks for your help,
A+!
Hey Bruno, I wasn't aware your pedal was unusable, or I would of course take it back. I've got Causality back on the breadboard to sort out a few issues and make some other improvements. A few things you can do yourself:
- Replace the resistor voltage divider R1/R2 with a 78L05. This will make the vref dead solid.
- Replace R33 (10k) with a socket. Try 47k or 100k in it's place
It may be the LED indicator is causing ticking in your unit. Disconnect and see if it goes away.
Anyway, I'm happy to do this work for you if you want to sent the unit back to me. And, lets use PM rather than this thread to discuss it please.
Rick
OK, Rick,
QuoteHey Bruno, I wasn't aware your pedal was unusable, or I would of course take it back. I've got Causality back on the breadboard to sort out a few issues and make some other improvements. A few things you can do yourself:
•Replace the resistor voltage divider R1/R2 with a 78L05. This will make the vref dead solid.
•Replace R33 (10k) with a socket. Try 47k or 100k in it's place
It may be the LED indicator is causing ticking in your unit. Disconnect and see if it goes away.
The question is not to return the instrument to you, but having directions from the designer on how to fix some issues to make the unit functioning properly to be usable, and I am sure that the informations given here will be of a
great interest to the other C4Mk2 owners or builders to make their unit work
flawlessly... Didn't I said in my previous posts here that otherwise the C4Mk11 was an unusually featured and good sounding phaser, by the way ?
Nonetheless, thanks Rick for your reply - Of course I'll let you know if these solutions are satisfactory, or if I found anything else / or even better...
A+!
i built it from sundgist layout, but when i turn the regenpot or the dephtpot to far, i got a totally bass distorted sound! :icon_sad:
does some got an idea whats up with my built? checked it twice, can't find a mistake!
thanks mäk
http://dl.dropbox.com/u/967492/No%20Quarter.mp3
Audio path:
Rick's fingers >>> Rhodes 73 MkI >>> Causality 6 >>> Roland Bolt 60 watt tube combo >>> Shure SM58 >>> Wavelab
(http://dl.dropbox.com/u/967492/Cvi/CVi03.jpg)
Wow, sounds great!
Quote from: frequencycentral on May 30, 2011, 11:49:48 AM
http://dl.dropbox.com/u/967492/No%20Quarter.mp3
Audio path:
Rick's fingers >>> Rhodes 73 MkI >>> Causality 6 >>> Roland Bolt 60 watt tube combo >>> Shure SM58 >>> Wavelab
Legend.
Has anyone built this layout yet? I built a casualty 4 sometime ago and thought I give this a try if the layout was confirmed.
Quote from: frequencycentral on October 18, 2010, 05:53:37 AM
Based on Mark Hammer's addition of 2 extra stages to his build, I've made a new layout for "Causality 6" - as yet unverified, and it could do with a set of sharp eyes to check it for errors....... :icon_biggrin:
Features:
- 2 extra OTA stages that can (optionally) be switched in or out via a DPDT.
- Provision to add even more stages.
- Pads for wet only mod.
- Optional odd/even stages in the regen path (parity switch).
- Input section options (R38, C12/R37)
- Polarity protection (D3).
- Pads to fit pretty much any size trimmer in the VR1 position.
This is a little speculative. I'm assuming the extra stages will work as shown, and that the parity mod will do also. My experience tells me that it will. I'm planning to use two of these PCBs for my super-duper-semi-modular Causality when I eventually get around to it.
The original Causality 4 board was 20 x 22 pads, the Causality 6 is 21 x 25 pads, just a bit bigger - nice job Rick!. It should still fit in a 1590B, though a 1590BB build will be easier, especially if all the options are incorporated.
As is customary, I am happy to receive any PCBs that folks might want to send my way! ;D
(http://dl.dropbox.com/u/967492/C6%20PCB.gif)
(http://dl.dropbox.com/u/967492/C6%20PnP.gif)
I've built a couple. It has an error. Should be a 10k to vref from pin 12 of IC3. I also had issues with the vref being really low, still haven't figured out why. My fix was to omit R26 and R27 and use a 78L05 for vref instead, kludged into the general area the R26/R27 took up. I also omitted the parity switch and hooked up the 50k regen pot with odd parity at lug 1, even parity at lug 3, lug 2 to the 'Regen lug 2 (blue pad)', which works nicely, though in C4 stage mode one end of the pot (even parity) does a kind of tremolo thing, as then the regen is only over 2 stages. I do need to update this layout with the mods mentioned above and a few other value changes I made, as I'm planning for two of these PCBs to be the basis of my forthcoming Gemini Dual Core Phase Shifter (http://dl.dropbox.com/u/967492/Gemini%20Phase%20Shifter.jpg).
Thanks for the reply.
Let me see if I understand what is going on here.
There are stages of phase shift, two fixed and 4 swept. The first and last stages are fixed.
The swept stages seem to use the caps for phase shift while the first and last stages use a decade difference in caps.
The regen control seems to be a little more than regeneration. Looks like it's mixing the output of stages 4 and 5 back into the input of stage 1. Seems like there is always some regeneration going on.
Hey Rick, do you feel the odd/even parity switch on the regen path is worth having? Is the difference really audible?
Also, do you know a way to switch between three sets of stages (e.g. 4/6/8 or 4/8/12)?
Quote from: soggybag on June 05, 2011, 12:34:46 AM
The regen control seems to be a little more than regeneration. Looks like it's mixing the output of stages 4 and 5 back into the input of stage 1. Seems like there is always some regeneration going on.
A 'normal' regen pot would be 10k, which is enough for there to be no regen at it's maximum resistance. The way I've got the regen 'mix' pot set up gives no regen in it's mid position, with the ability to dial in 'odd stages regen' at one end, 'even stages regen' at the other.
Quote from: Beo on June 05, 2011, 04:15:15 AM
Hey Rick, do you feel the odd/even parity switch on the regen path is worth having? Is the difference really audible?
I like it a lot, two different flavours. There is a difference. I'm not aware of anyone else who's messed with multiple regen taps. Have a listen to what it can do on a 14 stage phaser: http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg739608#msg739608 IMO, this kinda stuff is really interesting, breaks new ground, and is the future. :icon_biggrin:
Quote from: Beo on June 05, 2011, 04:15:15 AM
Also, do you know a way to switch between three sets of stages (e.g. 4/6/8 or 4/8/12)?
Sure, if you hook up the output of each swept phase stage to a rotary switch, with the common going to the input of the last fixed phase stage, you can dial in any number of stages. Then look at my Sonic Death Ray design for how to configure multiple regen taps: http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg715075#msg715075
There is still soooo much fun to be had with phasers........
Finally got round to making up a box for this.
(http://dl.dropbox.com/u/15632336/lektronix/Photos/Causality1.jpg)
(http://dl.dropbox.com/u/15632336/lektronix/Photos/Causality2.jpg)
(http://dl.dropbox.com/u/15632336/lektronix/Photos/Causality3.jpg)
Had a can of glow in the dark paint so....
(http://dl.dropbox.com/u/15632336/lektronix/Photos/Causality4.jpg)
Have been meaning to add 2 extra stages and a filter toggle, finally able to get round to it.
Here's my vero layout.
(http://dl.dropbox.com/u/15632336/lektronix/StompFX/Causality%204/Causality%204%20%2B2stages%2Bfilter%20Stripboard.gif)
i like that glow in the dark lettering :D
So I have a pair of Causalities. One uses the standard LFO and employs a daughter board with an extra 2 swept stages, and the other has but the 4 stages and the variable-LFO-shape feature. The first one works fine, but the second produces a very audible "crunching" sound in sync with the LFO, that is not only an audible sound superimposed on the audio path, but actually impairs the clarity of the audio signal. It's like listening to someone walk on hard snow in time with the music. I can't for the life of me figure out what's wrong. It is tamed somewhat by adjustment of the width and range controls, but never really goes away completely.
Any suggestions?
Have you measured the vref? Is it stable?
can you get the sound of all "other" phasers (mxr, boss, etc) on this pedal?
After 2, I would say no. At least not without some fine tuning. You definitely get a nice range of usable sounds, but you can't really throw all nominal component values at it and get dead-on emulation right out of the box. There is also something to be said for the manner in which the various control elements (OTAs vs FETs) sweep through their range, producing a slightly different feel.
I built the C4 version 1 and I'm getting some distortion when I pick the G and B string. When I play soft the distortion isn't very noticeable if at all. It sounds like I'm holding something metal against the strings when I'm picking. Almost like fret buzz.
I didn't substitute any IC's. I changed R7 to 1K, R12 to 47K, and C4 to 47u. I used C10K for the Regen, B25K for the Speed, and 47K for the Depth and I get nice sweeps out of each.
The Depth pot seems a little weird to me though. I can really only use it at Max. When it's below max it gets pretty muffled.
Any ideas on the distortion issue or has anyone else had this?
Your guitar might be two loud! Turn down zee volume maybe?
I've tried it with 5 different guitars and got the same result with each. Humbuckers and single coils. It only goes away a little if I turn the guitar way down. I don't think guitar volume is the issue. I can't remember but I don't think it did this before I changed the timing cap and R7. I may revert them back to their original values and see if it still does it.
Here's a modular version, basically a C6 without an LFO, running on +/-12V:
(http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-front.jpg)
(http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-guts.jpg)
Here's some soundclips...
First, let's phase some pink noise:
http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-Noise.mp3
So now, with a couple of VCOs as audio, let's send S/H into one CV input then an ADSR into the other, while slowly turning up the resonance:
http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-SH-Env.mp3
Now, a single VCO as audio, with ADSR to one CV input of Continuum, and slowly introducing a -1oct sub osc to the other CV input:
http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-FM1.mp3
Finally, here's how it sounds phasing my RS-09:
http://www.frequencycentral.co.uk/wp-content/uploads/2012/07/Continuum-RS09.mp3
I'd be really grateful for opinions on how it sounds!
Well, it sounds absolutely lovely.
And without wishing this to sound like any sort of criticism, ALL phasers sound great with sustained wide bandwidth source material like string synths (RS-09) or noise-based sources, as do all flangers. They can sound less majestic and inspiring when feeding them material like guitar, that has a narrower bandwidth to start with, and only has its widest bandwidth for the first few moments after picking. Remember that those notches don't make much difference when sitting above the spectral content of the signal. Like I say, that's not a criticism of the design, just a reining in of the expectations of folks who might build one and say "Hey, how come mine doesn't sound anywhere near that good?". The answer is "Because the notches spend a lot of time up here, and your signal kind of ends down here."
I might also say that the modulation is a big part of why these clips sound so nice. Much smoother sweep than I get on my C4 and C6. Curious about the modulation source used. Loved the S&H-plus-ADSR sounds, the little glissando "droop" at the end of each clocked step was neat and added some real character.
Point taken Mark, probably why I like my phased guitar to be fuzzed-out first. ;D
Modulations used were a modular version of Electric Druid's TAPLFO2:
http://www.frequencycentral.co.uk/wp-content/uploads/2011/09/Panel.jpg
...('sweep' waveform, ie hypertriangular) and my modular version of Electric Druid's LoopEnv1:
http://www.frequencycentral.co.uk/wp-content/uploads/2011/09/Recycler-panel.jpg
What I do find interesting is that with the more complex modulations, ie not your bog standard up/down sweep, my brain thinks it's listening to a regular filter rather than a phaser - even though I know what's really going on, my brain thinks up/down sweep = phaser, anything else = filter...
Quote from: frequencycentral on July 23, 2012, 03:54:32 PM
What I do find interesting is that with the more complex modulations, ie not your bog standard up/down sweep, my brain thinks it's listening to a regular filter rather than a phaser - even though I know what's really going on, my brain thinks up/down sweep = phaser, anything else = filter...
If you have the opportunity to give the ToneCore Liqui-Flange a listen, do so and you'll find the same thing. It's very diffiocult to tell the difference between the envelope-controlled sweeps, and "stepped" (S&H) flanging, and the same thing with a filter. However, I suspect that phenomenon occurs primarily with higher resonance settings, since the peaks created shift attention here, then there, then there, just like they do with filters.
Bravo Rick, love the mod version.
rick,
forgive me if i asked before...but my bwain is widdle...
i finally got some lm13700's in...
do you know of a VERIFIED vero layout for the causality? i really wanna build one, but it's gotta be on vero...
and i've learned to not trust layouts found on the internet too much unless a couple peeps have built them, so i figured i'd
ask!
thanks bud!!
can't wait to get this thing going. ;)
You could try this one: http://tagboardeffects.blogspot.co.uk/search/label/Phaser
IvIark hangs out at the other place mostly, which reminds me, I owe him a PM...
Quote from: frequencycentral on July 23, 2012, 03:54:32 PM
...('sweep' waveform, ie hypertriangular) and my modular version of Electric Druid's LoopEnv1:
What is hypertriangular?
EDIT: Google seems to think it's what synth guys call a parabolic waveform, right?
hyper super extra... a sharp/steep triangle/sawtooth?
*googles* oh, i see... right.
Quote from: merlinb on July 24, 2012, 02:53:16 PM
Quote from: frequencycentral on July 23, 2012, 03:54:32 PM
...('sweep' waveform, ie hypertriangular) and my modular version of Electric Druid's LoopEnv1:
What is hypertriangular?
EDIT: Google seems to think it's what synth guys call a parabolic waveform, right?
http://userdisk.webry.biglobe.ne.jp/000/024/65/1/200510_img_4.gif
Quote from: frequencycentral on July 24, 2012, 01:40:22 PM
You could try this one: http://tagboardeffects.blogspot.co.uk/search/label/Phaser
IvIark hangs out at the other place mostly, which reminds me, I owe him a PM...
thanks rick,
i've got IvIark's layout from there, but some people's reports make me a wee bit leery about building it.
i'll try comparing it to the schematic, maybe i can give it a whirl.
thanks bud! ;)
There have been at least 3 people let me know they've built it ok now Jimi. Unfortunately when there's an issue with the first person to respond it makes people worry, but I have no control over operator error.
gotcha Mark...
i will give it a shot then, may be my swan song with this for a while.
thanks for the heads-up!
Quote from: frequencycentral on July 24, 2012, 03:09:37 PM
Quote from: merlinb on July 24, 2012, 02:53:16 PM
Quote from: frequencycentral on July 23, 2012, 03:54:32 PM
...('sweep' waveform, ie hypertriangular) and my modular version of Electric Druid's LoopEnv1:
What is hypertriangular?
EDIT: Google seems to think it's what synth guys call a parabolic waveform, right?
http://userdisk.webry.biglobe.ne.jp/000/024/65/1/200510_img_4.gif
Correct. Quick ascent to the "top" of the sweep/spectrum, where more change/movement is needed in order to be perceived, and deccelerating descent into the lower part of the sweep where only small changes are needed to detect change.
That translates into an LFO waveform that looks sinusoidal for the lowest part of the sweep, and triangular for the highest part of the sweep.
Note that this is most useful when sweep is relatively slow. I'll pull a number out of thin air and say, quite arbitraily, LFO rates of 0.5hz and slower. Once you get faster than that, the comparative advantage of normal triangular, or sinusoidal, over a composite of the two, pretty much vanishes.
:o necrobump!
so, this one left without really finalizing everything..
questions:
1.) which is the most stable build (c4, c4mkII, c6)
2.) best mod/most usuable mod for the ^ stable build.
.. i know the entire thread could give me answers.. but having read everything.. it left me quite hanging.. (this thread actually made me very excited since the only build i have left to do in my "to do list" was a phaser..
anyway.. for the nth time, i know you've had many of these, mr. Rick Holt >>>>>>>>> ;D THANK YOU SOOOOOO EFFFFIN' MUCH!!! ;D thank you thank you for putting up this build and for the other builds that i have silently stalked ;D.. thank you so much!
hi guys,
i've built this using this layout http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html (http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html) and it more or less works, but i'm having a weird issue with the sweep and although there seems to be some past discussion of this problem, it's not entirely clear to me how to fix this one. basically, the sweep seems to reach its peak and then "resets"; goes up but not back down. does that make sense?
i've nubishly deduced that this is LFO vbias related. ?
would a voltage regulator/zener/simpler fix resolve this? switching the top resistor in the LFO's voltage divider for a 78L05, while stabilising the vref, results in no sweep. but i'll try again tomorrow.
cheers for any help!
Quote from: MrStab on July 05, 2013, 06:38:38 PM
hi guys,
i've built this using this layout http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html (http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html) and it more or less works, but i'm having a weird issue with the sweep and although there seems to be some past discussion of this problem, it's not entirely clear to me how to fix this one. basically, the sweep seems to reach its peak and then "resets"; goes up but not back down. does that make sense?
i've nubishly deduced that this is LFO vbias related. ?
would a voltage regulator/zener/simpler fix resolve this? switching the top resistor in the LFO's voltage divider for a 78L05, while stabilising the vref, results in no sweep. but i'll try again tomorrow.
cheers for any help!
same here.. it disappears after it swooshes up.. :icon_cry:
if you scroll down to the very last comment(s) on the layout link i posted, gambit, there's a third victim! and possibly a fourth on another popular forum. my Vref on the LFO was fluctuating at about 3-4V, but as i mentioned a 78L05 just kills the sweep. maybe i should put the volt reg and then a resistor in series to lower back down to a constant 4-ish instead of 5V?
i can't experiment at the moment as i'm awaiting solder, but this seems to be a "known" thing. keep experimenting, i'll do the same!
yes, i think i came across that 4th victim too.. will try to breadboard (though i hate breadboards) to see if i can do something about it..or maybe use sockets on "modifiable" areas on my build.. will also let you know if something comes up.. thanks!
from another (let's face it, the other) stompbox forum:
"sundgist wrote:
Taking vref on the lfo buffer/gain stage from the lfo's voltage divider causes the lfo to swandive just before it gets to each positive and negative peak. I've moved the 10k resistor and wire along a bit and added a link to the main power supplies vref."
assuming this is the problem, i'm pretty sure i'd tried stabilising with the main vref that way, only to kill the effect
Quote from: MrStab on July 10, 2013, 01:12:28 PM
from another (let's face it, the other) stompbox forum:
this reminded me of this: http://security.stackexchange.com/questions/33470/what-technical-reasons-are-there-to-have-low-maximum-password-lengths
QuoteTake five chimpanzees. Put them in a big cage. Suspend some bananas from the roof of the cage. Provide the chimpanzees with a stepladder. BUT also add a proximity detector to the bananas, so that when a chimp goes near the banana, water hoses are triggered and the whole cage is thoroughly soaked.
Soon, the chimps learn that the bananas and the stepladder are best ignored.
Now, remove one chimp, and replace it with a fresh one. That chimp knows nothing of the hoses. He sees the banana, notices the stepladder, and because he is a smart primate, he envisions himself stepping on the stepladder to reach the bananas. He then deftly grabs the stepladder... and the four other chimps spring on him and beat him squarely. He soon learns to ignore the stepladder.
Then, remove another chimp and replace it with a fresh one. The scenario occurs again; when he grabs the stepladder, he gets mauled by the four other chimps -- yes, including the previous "fresh" chimp. He has integrated the notion of "thou shallt not touch the stepladder".
Iterate. After some operations, you have five chimps who are ready to punch any chimp who would dare touch the stepladder -- and none of them knows why.
Quote from: artifus on July 10, 2013, 01:33:17 PM
QuoteTake five chimpanzees. Put them in a big cage. Suspend some bananas from the roof of the cage. Provide the chimpanzees with a stepladder. BUT also add a proximity detector to the bananas, so that when a chimp goes near the banana, water hoses are triggered and the whole cage is thoroughly soaked.
Soon, the chimps learn that the bananas and the stepladder are best ignored.
Now, remove one chimp, and replace it with a fresh one. That chimp knows nothing of the hoses. He sees the banana, notices the stepladder, and because he is a smart primate, he envisions himself stepping on the stepladder to reach the bananas. He then deftly grabs the stepladder... and the four other chimps spring on him and beat him squarely. He soon learns to ignore the stepladder.
Then, remove another chimp and replace it with a fresh one. The scenario occurs again; when he grabs the stepladder, he gets mauled by the four other chimps -- yes, including the previous "fresh" chimp. He has integrated the notion of "thou shallt not touch the stepladder".
Iterate. After some operations, you have five chimps who are ready to punch any chimp who would dare touch the stepladder -- and none of them knows why.
So if I read this correctly we're not supposed to install some chimps.......Which chimps are we supposed to leave out? ;D
i generally tend to avoid the ones who are not already banging rocks together.
so, from what i understand, 2+2=5? :)
yep - do it to julia.
moving on from the event that never happened, i put a 78l05 back in, no effect, and lowered vref to about 4.5V with a 1n4001 (not sure why i thought that would work, but i thought screw it, might as well try and simulate what it would've been with the divider), still nothing.
i have a severed wire from experimenting between where Shape lug 1 meets the diode to ground and the main circuit vref, which, if i touch together then separate, gives me one solitary sweep. doesnt seem to be any considerable difference in voltage between the two extremes. clue?
i'll keep mindlessly poking stuff as ever
if i connect aforementioned wires, then turn Regen full, it squeals out the LFO rate, then when i put it back down, it continuously phases although weak.
Pin 1/output A of LFO opamp (tried a few different ones inc. 4558, TL072 and OPA2227) is consistently too high, even with nothing in the socket. 6-7V.
source voltage has drooped to 7.5V or something since switching the 78L05 regulated vbias attempt
things i've tried:
- separating LFO IC's power and placing a 1000uF cap to ground
- separating the V+ of the LFO's voltage divider from the V+ on the quad opamp and placing a 470uF to ground (not sure why that would make any difference, but meh)
- Voltage-regulated vbias as previously mentioned
decoupling came to mind because the circuit "thumps" when speed is on full. anyways, no dice - while the sweep does seem a bit smoother, it's still lop-sided. the Shape pot at full CW & CCW and the speed LEDs give an insight into the disproportionately sharp rise of the sweep.
thinking i should just start over from another layout, checking as i go with the schematic, but it's a pain when there's probably just one fix.
I got the same thing going on too, for the squeel on the regen pot and sometimes distortion, i put a 2k7 on lug 3 of the regen. it helped with that, but still lopsided phasing.
does your Regen pot only squeal when you turn it near full clockwise, jimilee?
having relentlessly trawled the web for solutions to various hardware problems for years, it's actually reassuring that quite a few of us seem to have the same problem. this phaser just sounds really, really cool even when it's not working properly!
Quote from: MrStab on July 18, 2013, 10:49:32 AM
this phaser just sounds really, really cool even when it's not working properly!
+1 here.. not sure with the squeeling you were referring to though.. anyhow.. i'l build another one, just for the heck of it.. was waiting for the parts and got them now.. i wont rush to finish the build this time.. wish me luck!
the idea of rebuilding the whole thing kinda bugs me in case it doesn't work again and i waste more parts, but good luck nonetheless.
if i take the plunge, i'll probably use this layout, double-checking with the schem as i go: http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard%20Corrected.gif (http://www.sundgist.talktalk.net/Layout/Causality%204/Causality%204%20Phaser%20Stripboard%20Corrected.gif)
Quote from: MrStab on July 18, 2013, 10:49:32 AMdoes your Regen pot only squeal when you turn it near full clockwise, jimilee?
having relentlessly trawled the web for solutions to various hardware problems for years, it's actually reassuring that quite a few of us seem to have the same problem. this phaser just sounds really, really cool even when it's not working properly!
in certain settings. Phreak over at Byoc suggested removing the shape pit and replacing the speed pot with a 1mc. I haven't done this yet but that's next. Adding the resistor did kill some squeal and distortion. Checking the solder joints on this thing is tedious as hell, but I found a few bridges ones. That helped also.
Quote from: jimilee on July 22, 2013, 02:22:24 PMin certain settings. Phreak over at Byoc suggested removing the shape pit and replacing the speed pot with a 1mc.
thanks for sharing, jimi. amidst all the experiments, i've somehow stopped mine from working altogether (*sigh* typical...) so i'll need to resolve that before i can try myself.
i theorise that either
everyone who built the phaser from that layout is having problems but just don't realise it, or we all got it right but think otherwise. lol
or maybe it really is just anally relentless with the parts used. in any case, i just can't see the difference between the TagBoardEffects layout, the other layout i posted and the schematic itself to try and narrow down this problem. damnit! wish i wasn't such a layman. c'mon, you pros! throw us a bone!
I'm guessing everyone that built this is having issues or figured it out. As I am a solder by numbers type of guy, I have no idea how this solution helps,but he said it helped his.
With etched boards you gotta watch for solder bridges for sure,they're far to easy to make when working this stuff out.I had an Octavia that I successfully disabled for many months one time trying to work stuff out.
i'm just using strip/veroboard for this, as my monotony might've suggested. you've just got me thinking - it can't be a problem with just the layout i'm using if you're etching yet we both have the same issue. i'm a bit slow, in case you figured that out already...
what i tried:
-taking out the Shape pot. wasn't sure how to hook up the stray wires, so i tried all combinations. they all still showed a "preference" for one side of the sweep. connecting lugs 1 & 3 made it permanently fast, though.
-put 470k resistor in series with Speed pot just to simulate 1M, didn't really affect the above much.
it's late (7am, i'm clearly the employed sort), but i'm starting to wonder after watching the sample vid again (https://www.youtube.com/watch?v=eqjmauZ7Dao (https://www.youtube.com/watch?v=eqjmauZ7Dao)) whether or not there is a problem with my build after all. it just doesn't feel right, it's like i need some weird time signature to play along with it smoothly.
either way, the Regen pot shouldn't squeal at max (it makes some cool police car sounds...) and there shouldn't be thumping when Speed is at max either. so even if i am a moron and the sweep is fine, they remain issues.
Complete noob thought that may have been presented earlier in a better way... and this was a while ago so memory is sketchy...
I had a series of boost/dirt circuits that shared a common GND rail - it was possible to swing the gain on at least one of the circuits to an extreme and the whole thing would squeal as you've described. I never finished that box up, but I suspected I needed to prevent the resistance reaching zero somewhere along the way to prevent a zero R feedback loop somewhere else in the series.
Thumping sound I've got nothing for (unless its a hybrid circuit and something about it is allowing clock/lfo to bleed into audio path) - but you already knew that could happen and have eliminated that possibility I guess.
Quote from: mistahead on July 23, 2013, 02:31:17 AMI suspected I needed to prevent the resistance reaching zero somewhere along the way to prevent a zero R feedback loop somewhere else in the series.
hmm... i had pictured a solution based around what you mean, but i've been up all night so i got it all wrong lol. i'll have a ponder when i wake up. i have something similar (albeit minor) with a compressor's release pot squealing on 0 resistance, but i hadn't really connected the two. thanks for the suggestion, i'll get on that once i get the whole sweep thing sorted (if i even need to...).
i've tried decoupling the whole LFO, but no end to the thumping. maybe it's to do with the (white) LEDs i'm using, can't remember exactly but i think the current rating was on the higher side. it's only at full speed that this happens, which intuitively just seems like the circuit voiding its bowels to keep up.
Ldr led combo never going dark enough at the highest end of the speed variable, while the effect of one light pulse is still talking place the resistance doesn't change enough before the next pulse, resulting in the later pulse pushing through into the consequence of the one before?
If that made sense... Possibly waaaaaay off the mark even if it did...
Quote from: MrStab on July 23, 2013, 03:22:13 AM
Quote from: mistahead on July 23, 2013, 02:31:17 AMI suspected I needed to prevent the resistance reaching zero somewhere along the way to prevent a zero R feedback loop somewhere else in the series.
hmm... i had pictured a solution based around what you mean, but i've been up all night so i got it all wrong lol. i'll have a ponder when i wake up. i have something similar (albeit minor) with a compressor's release pot squealing on 0 resistance, but i hadn't really connected the two. thanks for the suggestion, i'll get on that once i get the whole sweep thing sorted (if i even need to...).
i've tried decoupling the whole LFO, but no end to the thumping. maybe it's to do with the (white) LEDs i'm using, can't remember exactly but i think the current rating was on the higher side. it's only at full speed that this happens, which intuitively just seems like the circuit voiding its bowels to keep up.
Increase regen series resistor/decrease cap value.
Yes making the LFO drive a high bright LED probably is causing thump.
Quote from: Scruffie on July 23, 2013, 09:49:44 AM
Increase regen series resistor/decrease cap value.
ah, so i was thinking right then. thats a first. the LED thing does make sense too.
i'm tempted to record a clip of how mine sounds later just so you guys can confirm whether i'm talking crap about the sweep or not. any ideas where i'd set the Shape pot to "default", ie. the resistance there'd be if the pot wasn't there at all?
Quote from: MrStab on July 23, 2013, 11:00:13 AM
Quote from: Scruffie on July 23, 2013, 09:49:44 AM
Increase regen series resistor/decrease cap value.
ah, so i was thinking right then. thats a first. the LED thing does make sense too.
i'm tempted to record a clip of how mine sounds later just so you guys can confirm whether i'm talking crap about the sweep or not. any ideas where i'd set the Shape pot to "default", ie. the resistance there'd be if the pot wasn't there at all?
Link to the schematic you used? (this thread's huge!).
sure thing, scruffie:
http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html (http://tagboardeffects.blogspot.co.uk/2012/02/causality-4-mkii-rick-holt.html)
(http://3.bp.blogspot.com/-yV7l2AivOY4/T0uqfbQzS5I/AAAAAAAAA4A/-AuRqY2LrjQ/s1600/Causality+4+MkII.png)
That's the layout, the schematic it's based on though.
ah, my bad - i have a bad habit of not reading things properly. to the best of my knowledge, it's this, give or take:
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4MkII.jpg)
here's a low-quality clip of some rung-out chords with the Shape pot in the middle position (the hiss & distortion are from the recording itself):
does the sweep seem right?
Shape would be the middle of the pot for 'normal' sweep but if that doesn't work you could pull the diodes and pot if you don't need it.
NE5532 is a pretty poor OpAmp for an LFO, has quite a high current draw so may well be the cause of your 'thump' you can try putting a large cap (47-100uF) straight across pins 8 & 4 (Positive to 8, negative to 4) making it drive an LED surely wont help much either.
Listening to your clip it sounds like a very poor hyper triangle with a dip at the top, possibly due to current issues. Does it improve with the range/width down?
i forgot to actually mention what opamp i was using: i've tried a TL072 (currently using that), a LM358 and an OPA2227 (even though the current on that last one isn't on the low side).
with Range and Width at 0, the transition seems a bit smoother but the disproportionate "jump" is still there. apologies for using a lot of layman's terms here.
as the only clues i could find beforehand pointed to current, as you mention, i tried giving the LFO a fixed vbias via. a 78L05 instead of the separate 220k voltage divider, but that killed the effect altogether (despite what seemed like the right voltage readings). think the cap between opamp V+ & Gnd might alleviate the sweep issue as well as the thumping? i should mention that the sweep problem occurred whilst i was skipping the LEDs altogether.
thanks for the help!
Edit: a 1000uF (overkill much!) didn't kill the thumping, although i recall a big improvement in the TL072 over the OPA (as is to be expected, i guess) so im not too concerned about that - i'll switch out the LEDs for something less current-hungry at some point. unless ofc it's directly related to the sweep issue
Will replacing r12 with a trimmer allow us to bias the phase?
(https://dl.dropboxusercontent.com/u/5560115/Causality%204%20MkII%20New%20PCB.gif)
Quote from: MrStab on July 23, 2013, 03:07:30 PM
i forgot to actually mention what opamp i was using: i've tried a TL072 (currently using that), a LM358 and an OPA2227 (even though the current on that last one isn't on the low side).
with Range and Width at 0, the transition seems a bit smoother but the disproportionate "jump" is still there. apologies for using a lot of layman's terms here.
as the only clues i could find beforehand pointed to current, as you mention, i tried giving the LFO a fixed vbias via. a 78L05 instead of the separate 220k voltage divider, but that killed the effect altogether (despite what seemed like the right voltage readings). think the cap between opamp V+ & Gnd might alleviate the sweep issue as well as the thumping? i should mention that the sweep problem occurred whilst i was skipping the LEDs altogether.
thanks for the help!
Edit: a 1000uF (overkill much!) didn't kill the thumping, although i recall a big improvement in the TL072 over the OPA (as is to be expected, i guess) so im not too concerned about that - i'll switch out the LEDs for something less current-hungry at some point. unless ofc it's directly related to the sweep issue
358 is probably the best of that bunch to use, I favor the 1458 my self.
Could be related to the sweep issue yes, or you may just need to adjust the current to the OTAs Pin1 & 16 via the 4k7, raising it very slightly (don't lower it, too much current could pass and kill the OTA) may reduce the current and stop the OTA 'overshooting' I guess you could say.
I see the regen doesn't use a cap, adding one in series with that resistor may help tame oscillation, letting only higher frequencies through.
Quote from: jimilee on July 23, 2013, 06:13:36 PM
Will replacing r12 with a trimmer allow us to bias the phase?
(https://dl.dropboxusercontent.com/u/5560115/Causality%204%20MkII%20New%20PCB.gif)
From what I can tell with a quick trace is that is to boost/reduce the output volume should it be needed.
Quote from: Scruffie on July 23, 2013, 06:53:00 PM... adjust the current to the OTAs Pin1 & 16 via the 4k7, raising it very slightly
i tried raising it from 5.7k up to about 15k to no avail - it didn't seem to affect much. good call though, i've messed around enough with the LFO section and i didn't think of adjusting the OTA.
i'm at a loss for ideas now. the LFO opamp's V+ pin fluctuates, which is likely
the cause, but a few attempts at decoupling have done nothing. i have no 9V regulators available (even though reading is closer to 8), and all i have are a bunch of 9V zeners. maybe i should hook up the LFO to another power supply altogether and claim the effect is so badass it needs two adaptors. lol
V+ fluctuates by like 5-10mV, whereas vbias goes absolutely crazy by about 2.5V.
i'd already tried the bias pot you mentioned, jimi. sorry, should've said.
Quote from: MrStab on July 23, 2013, 08:10:08 PM
Quote from: Scruffie on July 23, 2013, 06:53:00 PM... adjust the current to the OTAs Pin1 & 16 via the 4k7, raising it very slightly
i tried raising it from 5.7k up to about 15k to no avail - it didn't seem to affect much. good call though, i've messed around enough with the LFO section and i didn't think of adjusting the OTA.
i'm at a loss for ideas now. the LFO opamp's V+ pin fluctuates, which is likely
the cause, but a few attempts at decoupling have done nothing. i have no 9V regulators available (even though reading is closer to 8), and all i have are a bunch of 9V zeners. maybe i should hook up the LFO to another power supply altogether and claim the effect is so badass it needs two adaptors. lol
V+ fluctuates by like 5-10mV, whereas vbias goes absolutely crazy by about 2.5V.
i'd already tried the bias pot you mentioned, jimi. sorry, should've said.
The OTAs in the chip should be matched well enough not to need separate resistors so that's good that it didn't work sort of, clears that of being the issue.
So we head back to the LFO, it shouldn't need regulating, get rid of those LEDs if you haven't already and see if there's a change.
Having a think about it, I now wonder if it's an issue with NOT using a NE5532...
the issue was present before i had LEDs hooked up, unfortunately - i just wired the anode & cathode wires together at first.
i've been holding caps across all 3 IC's (soldered one across the TL074 & am ensuring contact with the rest) but still getting voltage fluctuation. i even separated the LFO V+ from the rest of the circuit at one point.
you may have noticed this from a few pages back, but i copied this from another forum:
"sundgist wrote:Taking vref on the lfo buffer/gain stage from the lfo's voltage divider causes the lfo to swandive just before it gets to each positive and negative peak. I've moved the 10k resistor and wire along a bit and added a link to the main power supplies vref."
pretty sure i tried that, too. while it sounds like the same effect, it doesnt sound like the same cause.
there's a response at the very bottom of the layout page to someone having the same problem, where they question the opamp usage, and the response is: "nope. in mine the TL072 and NE5532 sound nearly identical and operate the exact same way." not exactly scientific, though
If i'm reading the layout you used correctly (and i've had a few beers) width 2&3 go through a 47k resistor instead of a 10k to the main V.Ref (Row 3, width 3) that would increase the LFO gain, drop it to 10k and see what happens.
Only the LFO would need a cap across +/- the TL074 & 13600 shouldn't need it.
no success, but progress! changing that 47k for a 10k made the problem worse, which seems good from a diagnostic standpoint. it flips back to the peak (?) of the sweep much more snappily. should i try going over 47k instead?
Edit: scratch that, 100k just speeds up the effect but still has the problem. interestingly, the LED thumping has now gone. there's a kinda scratchy sound as the sweep descends.
Quote from: MrStab on July 23, 2013, 10:04:50 PM
no success, but progress! changing that 47k for a 10k made the problem worse, which seems good from a diagnostic standpoint. it flips back to the peak (?) of the sweep much more snappily. should i try going over 47k instead?
Edit: scratch that, 100k just speeds up the effect but still has the problem.
woops, said i'd had a few haha, yup decreasing that increased gain.
No idea why that increased the speed at the moment.
I'll see what I can think of tomorrow.
i may have accidentally turned up the speed pot, now i think about it...
mucho cheers for the help so far man, you've suggested more after a few beers than i've managed sober lol. it is kinda late round this neck of the woods. i'll sleep on it as well
i know it's bad practise not to mention parts substitutions, but i've just realised i have 1.5K resistors in place of the 1.8. could this be to blame?
Quote from: MrStab on July 24, 2013, 10:33:02 AM
i know it's bad practise not to mention parts substitutions, but i've just realised i have 1.5K resistors in place of the 1.8. could this be to blame?
That's such a mild difference, pretty sure wouldn't be able to tell. Glad things re getting better,Ive been working on mine too, but watching your progress. Rhere's a causality 6 out btw! :P
from what i've read, there's a version with an even more insane number of stages from FrequencyCentral. i could just do with 2 that work! :( lol
300Ω is small in most contexts, but all other ideas have been thoroughly exhausted. it'd mean something like 0.044V difference i guess, so you're probably right. good luck with yours!
Quote from: frequencycentral on November 28, 2009, 11:44:43 AM
I've corrected the perf layout (and reveal) on page 2, so they reflect the Rev 1.2 schematic now on page 1.
Here's the PCB layout and it's Pnp, It's a bit different to the perf layout in that I've tried to lie the resistors flat wherever possible, though I guess you could build a perf layout from the PCB layout - much easier to follow actually, with the colour coding of +ve, ground and vref.
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/Causality4PnP.gif)
I've built the PCB version on page 3 and it works perfectly so maybe that layout can give some clues to what's wrong.
thanks Bill - could come in handy. i see yours doesn't have the Shape pot - i wonder if something went wrong when that was implemented in the design.
R7 in your layout appears to be 10K whereas it's 1k in mine. i've only looked at the LFO kinda region for now.
Yeah, I was thinking it might be a layout issue or something that was added since the first incarnation.
Just wanted to point out that this version worked fine for me and it might be worth looking at.
Seems like it would be easy enough to remove the Shape control and the resistor value that's different around the op-amp and see how it's working for you. If all worked well, the problem lies in the shape control itself and/or the one resistors value.
corrected R7, and jumpered inverted input with opamp output which was also lacking. all that did was lower the maximum speed and, interestingly, makes LED that represents the peak (?) fade but never go off.
it's hard to compare because of information overload but hey that's 2 disparities so far!
at first i ruled out this thread that i came across, but i wonder if there's some common ground here as it's still OTA-based phasers involved: http://www.diystompboxes.com/smfforum/index.php?topic=88625.msg748896#msg748896 (http://www.diystompboxes.com/smfforum/index.php?topic=88625.msg748896#msg748896) (no, not actually common g... nevermind). that specific post i linked to describes an uneven voltage divider for a more particular voltage than the 50-50 split of the Causality, but i think i recall another post from a thread about Causality where weird, un-repeatable voltage divider issues occurred until the vbias resistors were changed (still even values but lower values, iirc). might even have been FrequencyCentral? i may have imagined that.
so i wonder if it's these resistors i need to play around with. i built myself a 2nd Phase 45 last night and need to fix the sweep on one for a friend weirdly enough (probably FETs mismatched by like 0.01), but hopefully i won't get sick to death of phasers just yet!!
Hi again guys. especially Mr. Stab.
I finally got it working.. but not much like the one's with youtube demo's. But still, it works... my main problem now is the speed control pot. I don't have any rev log pots, so Im currently researching about how to change linear tapers into audio tapers.. and the regen seems to dial in the sweep quite fast.. might tinker with it too..
here are some pictures I took while making it.. modified it later to markII..since i started to rebuild MarkI first to try and pick out what I did wrong before.but this one end up working the first time I fired it up..
(https://dl.dropboxusercontent.com/u/27297380/DSC02635.JPG)
(https://dl.dropboxusercontent.com/u/27297380/DSC02632.JPG)
one other thing, rick, if you're still here in this thread.. How do I get the regen to "really do its job"? It seems like, I get only a subtle change when its midway then just a "good" change when maxed; not really a great change in the effect/swoosh or phasing maybe...i dont know what to call it.
And.. to no avail, I can't get the needed pot for the speed control..been tinkering on how to change the taper of linear pots, but still seems to squish all the usable speed at the last quarter turn of the pot.
also for the rate led, I couldn't get the other LED to completely turn off like the other one (wax an wane, the other one doesn't like to take rests in between..such a hardworking LED,stays on all the time).. it seems to stay on all the time. (even after endless mixing of speed,depth, width, shape pots)
I'd really like to make this my one and only phaser as I really loved it. Such a great pedal for me! and im keeping it foreveeeerr! :)
Thanks Rick, hope I could hear from you soon.
???
bump
anything?
:(
no one's visiting this already..
:(
very sad..
Not seen a lot of Rick around these parts for a while, so you may not get an answer from him (I guess he's busy with his modular synth stuff). I built this a while back using a board from Rick - works well - so I'd suggest re-checking your build for shorts, gaps, etc. The underside looks neat enough, but you never know...
hi again Gambit, glad you got it working! i wound up using a Phase 45 i made instead, it's grown on me but for some reason i like the LM13700 chip so i might try again some day...
your Regen issue might not be a case of taper - if i remember correctly, the Regen pot decreases the resistance as you turn it clockwise, so maybe you just need a smaller pot? worth a try at least
Quote from: MrStab on November 24, 2013, 08:47:01 PM
hi again Gambit, glad you got it working! i wound up using a Phase 45 i made instead, it's grown on me but for some reason i like the LM13700 chip so i might try again some day...
your Regen issue might not be a case of taper - if i remember correctly, the Regen pot decreases the resistance as you turn it clockwise, so maybe you just need a smaller pot? worth a try at least
Thanks Mr.Stab! was really stoked when I hooked it to power and saw the rate leds do symmetrical fading.. and when I plugged in my guitar, BAM! Phasing for the entire night! haha!
yeah, I think you should give it another try (and maybe talk to it while soldering the last pcs of components.. hehe.. i did.. :icon_redface:).. it's an amazing design.. and this thing is quite versatile.. i could get a pseudo wah kind of funky rhythm with it.. now Im actually wishing it had tap tempo! haha.. (tap tempos are in the top spot of my DIY "learning" process right now.. but it require PIC's..which i am nowhere close to understanding them..)
anyway, I wish you luck on your builds Mr. Stab!
and oh, I'll try your pot suggestion for the regen.. hmm, do you have any idea about how to change a pot's taper? I've read RG's secret life of pots.. but it doesn't work on the causality.. i did every single combination you could do to the pot (resistor in parallel to lug 1&2, 2&3, 1&3..etc..) I just couldn't spread that speed range on the entire scale of the pot.. but still, my build is usable...
here's how it looks now:
(https://dl.dropboxusercontent.com/u/27297380/Photo%2011-25-13%209%2030%2026%20PM.jpg)
If the feedback/regen signal has a gain of more than 1x, the circuit will oscillate. So the maximum regen amount is set by how close you can get to unity without breaking into oscillation.
If you look at the stage where the regen signal returns to, yo will see a 10k resistor between input and out on that op-amp (its feedback loop), a 10 resistor from the regen going to the '-' pin, and another 10k going from the input buffer to that point as well. The 10k input resistors and 10k feedback resistor in that stage produce a gain of 1x....assuming that their 5% tolerances do not dictate otherwise.
???
If the regen resistor is 9.5k, and the feedback resistor in that stage is 10.5k (both at the outer edges of 5% tolerance), then the gain of that stage (for the feedback signal) is 1.1x. That may not seem like much, but it is enough to produce oscillation/howling.
So the 10k log ot for adjusting the regen is really more of a fine-tuning control, to add a bit more resistance in order to be able to stay safely away from oscillation. If a person wants to have a variety of regen settings, then I would suggest using a 50k pot, since a 10k pot doesn't really add enough resistance to change things appreciably. With a total regen resistance of 10k+50k, there will be very little regen fed back to the earlier phase-shift stage. As you reduce the pot setting and approach 10k, it will start to be sharper and sharper.
Ideally, a person probably wants to use a 9k1 fixed resistor, instead of 10k, and a 2k trimpot to set the absolute maximum regen possible before oscillation, and then use the suggested 50k pot to produce degrees of feedback less than that maximum. Either that or use 1% resistors all round, such that the actual values correspond precisely to the values shown in the schematic.
You'll find that a lot of commercial phasers and flangers incorporate a trimpot to set maximum regen, for precisely the reasons outlined. If a manufacturer uses 5% resistors, they have no guarantee that each and every unit will stay safely enough away from oscillation when the regen knob is maxed.
that looks awesome, Gambit! looks like you used the same knobs i usually do in my builds. wish i had the patience to be more comprehensive with enclosure measurements.
any ideas on the uneven sweep, Mark? it's been a while since i tried the circuit, so i can't remember the ins & outs that well, but it definitely had me stumped. it didn't help my perseverance that the board eventually came filled with confusing kludges in an attempt to fix it.
i gave my P45 a proper enclosure yesterday, after using a butt-ugly mains transformer box for months (at shows! when placeholders become permanent...). i've been looking at Rick/Frequency Central's not-too-talked-about "Phase Revolution" (adds 2 more stages), which seems pretty easy to retrofit with a switch, but i can't remember the values of the FETs i matched and 2n5952s aren't the kinda thing you can just grab 10's of for cheap. not hijacking, just redundant phaser talk! lol
Thanks Mr.Stab! yeah, it is a pain to measure pot alignments relative to the enclosure down to the very millimeter..but it's really worth the effort.. although I get excited most of the time and just pick a spot where to drill... :icon_biggrin: but this time, it was an overall exemption to my habits. :icon_smile:. everything was made with patience.. even down to the hand drawn "blue print-ish" design with a phase shift graph..haha.. :icon_biggrin: and yeah, those knobs (my last pcs) look really cool.. it actually came from my mxr dist + clone and another 3 knobber donor pedal.. but, what i do not like about them is the knurled plastic inside which creates a "memory crease" of it's own.. so you can't re position it with small increments..but overall, it looked great combined with the enclosure design!
Mr. IVIark, thank you for that in-depth explanation about the regen pot.. well, i know now why I hit the oscillation zone.. im using cheap resistors..(these may have 10% tolerance, :icon_sad: ) but I'll try that trimmer to set the max regen.. I'm sure that'l fix it. (or measure ones that are close to the exact value or maybe make some series resistors to achieve the exact values and sub them with those 10k's)
now, all im left is the speed knob.. having a modified linear taper pot to function as a log taper really spread out the slows but not the fasts.. now it's even harder to find a good slow speed..
I know the schemo calls for a reverse log.. but will it not be the same as the modified log pot? or if i used the reverse log pot, the fasts will be the ones spread out?
your enclosure art could be quite educational, Gambit - just try not to stare at it when you're meant to be playing a song lol.
you could try wiring up your modified Speed pot backwards, and although it'll work in the wrong direction, if your pot truly is logarithmic then it'll be reverse-log when backwards. if that makes sense. then you can see if a reverse log pot will resolve the issue.
you've probably read up on it already, but i've found the graphs & diagrams on this thread (specifically this page) to be quite handy:
http://www.diystompboxes.com/smfforum/index.php?topic=70732.40 (http://www.diystompboxes.com/smfforum/index.php?topic=70732.40) for working out the actual taper of modified pots.
finally built this.... hot damn, i'm lovin' it! thanks rick!! :icon_mrgreen:
Of course, Sir James, with all of the many distortions you have at your disposal, now is the time to see which of them responds most favorably to a phaser in front.
The thing about moving notches before a clipping circuit is that they will pull the signal down below the clipping threshold for different parts of the signal at different times, resulting in differing amounts of harmonic content for notes in different parts of the spectrum. The net effect is one of "animating" the tone. This stands in contrast to sticking a phaser after a distortion, where everything has pretty much the same amount of harmonic content, and the sweeping notches make some notes "hide" while others stand out.
mark.... my brother.... words to live by!! ^^^^^^^
haven't tried with any fuzz yet, still working out a couple minor little buggies, but last nite i turned the range down and depth some and messed with the regen... and man, into my typical blackface hotrod princeton it was THICK as molasses , almost like a .... i dunno what. it was definitely moving around the signal in some peculiar and completely unexpected ways.... could definitely get that classic throb, but it was more like
doing mescaline as opposed to lsd25 *ww1 era triplanes flying thru the old chromostones and ridiculously organic in a very peculiar way.
i'm toying with the idea of putting this in a crybaby or morley shell with an @55 load of knobs and switches.
i'm addicted.
the biggest issue i have is getting the taper right for the speed pot. it's really touchy when it gets fast, that rubber really hits the road.
dino hipped me to this page: http://www.diystompboxes.com/analogalchemy/emh/emh.html
which i never knew existed... looking like a 1m pot with a 2.7
M and 51k tapering resistor should get me in the ballpark. i need to spread out the last 10% a lot more.
mark, do you think this could be adapted to my fuzz idea?
like... make a multi voiced fuzz, and have two fixed and two swept stages with this kind of oscillator?
i'm wondering if maybe while this is still partially on the breadboard if i should try taking the blinky lights with some photoresistors feeding the input of some fuzzulars?
man. jus when i thought the madness was ending....
* don't try this at home :icon_eek: kids, and don't ask how i know this stuff... :icon_twisted:
edit:
M
Well, I don't know what you used, but LFO speed controls nearly always cry out for a reverse-log taper (which Rick does indicate in the schematic). If that does not get you the dialability you need then I guess the next thing might be to use something like a 200kC pot, where those last 50k ohms are stretched out even more, and if you need slower speeds, strap on a 270k-300k fixed resistor in series, using a toggle.
As for adapting it to "your fuzz idea", I'm not sure which variation of "that idea" we are talking about at the moment, given that a number of suggestions rolled in after the OP. As I recall, your intent was to switch/morph between different kinds of fuzz, as opposed to simply modulating one fuzz.
Maybe you want to take a peak at the Ibanez Flying Pan for some inspiration. That one combined a phaser and panner, such that the phaser was sweeping at one speed, and the phased signal was then swept between left and right outputs. My Line 6 M5 includes a model of it. I was never all that partial to it because I found the combination - especially the panning part, not subtle enough. I found it interesting for 20 seconds at a shot, but irritating after that.
On the other hand, let us say that a Flying Pan-like circuit fed two different fuzzes, whose outputs were mixed for a mono out, with the phaser going on in the background, and the panner morphing the final output between one fuzz and another. Is that a little more up your alley? (keeping in mind that a phaser->fuzz sequence is not quite as stark and dramatic as a fuzz->phaser sequence)
Quote from: Mark Hammer on February 25, 2014, 12:48:46 PM
Well, I don't know what you used, but LFO speed controls nearly always cry out for a reverse-log taper (which Rick does indicate in the schematic). If that does not get you the dialability you need then I guess the next thing might be to use something like a 200kC pot, where those last 50k ohms are stretched out even more, and if you need slower speeds, strap on a 270k-300k fixed resistor in series, using a toggle.
what i did was go to a 1m pot, with a 50k linear as a vernier for the last part of the sweep... can fine tune the fast speeds easier, and still get pretty slow to the point of almost sounding like a flanger. gonna open a 50kl pot, and wipe out the carbon at the bottom of the track... that way, when the 50k pot is all the way down, it will be out of the circuit.
Quote
On the other hand, let us say that a Flying Pan-like circuit fed two different fuzzes, whose outputs were mixed for a mono out, with the phaser going on in the background, and the panner morphing the final output between one fuzz and another. Is that a little more up your alley? (keeping in mind that a phaser->fuzz sequence is not quite as stark and dramatic as a fuzz->phaser sequence)
yes, please.
(http://i605.photobucket.com/albums/tt137/pinkjimiphoton/1976927_10202521941842703_145527064_zpsa624816f.jpg)
the phaser's done..
i modded it a little bit into a 6 knob 2 switch 4 led monstrosity with a remote jack for pretty much any expression pedal... works great with a roland ev5!
the on/off indicator is ultraviolet purple, left footswitch is in/out with true bypass and a grounded circuit board input in bypass so no background noise when it's off. other footswitch kills the dry signal to change it from a phaser (red) to a vibe (blue.. this led changes color).
but wait, there's more.. in addition to the afforementioned leds, the two inner ones pulsate back and forth at whatever speed the lfo is running at, and if you use the expression pedal input, you can see the speed change. it's hip. those are yellow and green blinky blinkys.
i added a 6th pot, fine which lets me fine-tune the upper range of the speed... it gets real fast when dimed, and the sweep is a little difficult with the speed pot alone. fine acts as a vernier to fine tune the speed. i opened up the pot and made it a "reverse no-load" pot by oblitterating the carbon track on the BOTTOM of the pot...unlike the top in a guitar. that way, when i turn it all the way down, counterclockwise, it takes the 50k fine pot out of the circuit and leaves the speed pot, which i'd doubled from 470k to 1 meg... so this thing can not only phase super slow, it can almost flange as well. and do tremolo. and vibratto. and chorusing. and phase the living phuck out of the synapses betwixt your brain cells. so anyways.. the most complex thing i have ever undertaken, here ya go... the causality 4 phaser, photon edition... stupid pedal trick and knobs to come...
the expression pedal jack is one of them plastic taydas, i used the switch connections on the jack itself.. when you pull theplug out, it defaults to a closed circuit with the 50k fine pot. i used only the tip/sleeve connections, no ground connection. worked out great. had just enough room to fit it between the two footswitches, and it actually is a good place for it..
avoided having to add any more switches by modding that pot. worked great too.
thought about using a 3p3t toggle with a 100, 10, and 30u cap, even built it up, but didn't install it. with the 1m speed pot, i can get it to phase REALLLLLLLLLLLL SLOWWWWWWWWWW, and with the vernier deal, i can dial it in easily.
tried making a tapered pot, but it just plain didn't work as well.
and yes, the knobs are crooked, intentionally.. two reasons... one, it let 'em all fit in a 1590bb without me having to get too smart and figure out exactitudes of measure far above my paygrade, and also cuz i think it'll look cool when the knobs are on ... kinda sine wave-y..
anyways... again... thanks rick for this great project, and everyone else who contributed every speck of knowledge i've gained here.. this is THE coolest thing i've built yet.
peace
SPT vid please...
cool build man, ive been looking at this for ages and never got around to it....but now i need a phaser again. i love em.
Quote from: pinkjimiphoton on February 25, 2014, 12:08:04 PM
man. jus when i thought the madness was ending....
And what exactly made you think THAT?
I made myself a Ross/Ropez some time back that had to have just about the widest sweep I have ever heard from a phaser in my life. It was like the A/DA flanger, for crying out loud. Just kept on going and going, and sounded like the phasing in the ELO tune "Strange Magic".
How'd I do it? There is a 10k resistor used to limit the current from the LFO in the Ropez. I dropped it down to 9k1. One doesn't want to reduce such resistors too much since applying too much current to the current-control pin can fry them. But it warrants experimenting with trimpots or other resistor values in OTA-based phasers so that he control current can be increased juuuuusssstttt a bit more to produce a wider sweep. One can always reduce the sweep width from that maximum, if desired.
Naturally ultra-wide sweeps are for the slow stuff, and bubbly settings demand a narrower sweep.
Quote from: deadastronaut on February 26, 2014, 02:54:46 AM
SPT vid please...
cool build man, ive been looking at this for ages and never got around to it....but now i need a phaser again. i love em.
i'm gonna talk to joe gagan and get a nice 50k wah pot from him with the cool gear so ya get more sweep, and put it in a chrome crybaby shell.
it works GREAT.. i'm using an ev5 right now, but the resistance is too small... ya want 50 or 100k.
this is like a vibe, phaser, chorus... i swear to god, almost flanging.
this is definitely on my board as of tonite.
vid as soon as i'm able... it would take like, 4-5 hours to go thru all the stuff this thing will do, it's sick!!
;)
used this last nite live... on almost every song. and got different sounds out of it every time.
i ditched the ev5 for an old crybaby shell, stuffed a 100k hotpot in there and one jack, with a footswitch to bypass the exp pedal.
it is @#$%ing sick.
anyways... stupid pedal trick as promised
http://www.diystompboxes.com/smfforum/index.php?topic=106323.new#new
So I have been working with the tagboardeffects version of this circuit
http://tagboardeffects.blogspot.com/2012/02/causality-4-mkii-rick-holt.html#comment-form
Having an issue with this phaser. I have it hooked up to my test rig and have sound coming through, and the Led's light in time and depth with the pots, but no phasing. I checked all my voltages to the ones Rick posted and they are all in line. The only issue is pins 5&7 on the LM13700. I am getting voltages of .58-.73 on those pins. I tried tracing back but am not seeing why I am ~5volts short there.
Any thoughts?
@dan_schu
My best advice is to ensure that you have all of your jumpers installed (there is one between Pins 5 & 7 of the 13700) and to make sure that all of the trace cuts are there.
Post voltage measurements as well. ;)
I'll quadruple check when I get home, but I am sure all the jumpers are there. I know for a fact that the one that connects 5 & 7 is there. I traced voltages from the 9V input to those pins. I was getting ~5volts up until the 33nf cap, then after that it dropped to 0.5V. I re-flowed and replaced the cap (just to take that out of the equation) and the voltages are still down.
Here are my voltages (this is with speed at min, shape middle, everything else max):
NE5532
1. 1.29v to 8.46v
2. 3.87v to 5.49v
3. 3.82v to 5.58v
4. 0v
5. 3.90v to 5.52v
6. 3.76v to 5.70v
7. 2.89v to 7.21v
8. 9.49v
TL084
1. 4.19v to 5.41v
2. 4.16v to 5.45v
3. 4.15v to 5.43v
4. 9.10v
5. 3.82v to 5.10v
6. 4.12v to 5.50v
7. 4.15v to 5.49v
8. 4.13v to 5.52v
9. 4.20v to 5.53v
10. 4.08v to 5.31v
11. 0v
12. 4.11v to 5.42v
13. 4.14v to 5.46v
14. 4.16v to 5.44v
LM13700
1. 1.26v to 1.35v
2. 0v
3. 4.02v to 5.40v
4. 4.06v to 5.39v
5. 0.42v to 0.56v
6. 0v
7. 0.43v to 0.57v
8. 4.12v to 5.42v
9. 4.10v to 5.39v
10. 5.10v to 6.62v
11. 9.49v
12. 5.12v to 6.62v
13. 4.17v to 5.42v
14. 4.14v to 5.45v
15. 0v
16. 1.26v to 1.35v
Thanks
Remove the 13700 (hopefully you used a socket) and check resistance between Pins 5 & 6 and then between 6 & 7 on the socket. I am wondering if you have a short to ground somewhere there... ???
I checked resistance between ground on those pins. Everything looked good, so no short there. I tested voltages on both sides of the 33nF cap off of pin 7. On the pin side, I was low, on the other side, I was getting 4.7-5.3 volts. I tried just replacing that cap with a jumper, which gave me the right voltage at pins 5&7, but still no phasing.
I'm thinking this is one of those that I should just retry building (maybe with a different layout) and see if it happens again.
Thanks
So I've built this and have room to spare on the perf for the addition stages daugter board.
Question is can I make it switchable and if so how.
Thanks
It's earlier in the thread. Can be done with a DPDT switch.
Thanks Rick
I've found it. Sometimes it takes me a while :icon_redface:
Rich
Just a quick one. Thanks Rick. It was a really enjoyable build but what a pedal? I built the Mk II, etching the PCB, then built the 2 extra stages on vero.
It sounds amazing. You can dial in what you want with the five pots, but what I love about it is the tone you can achieve with the subtle settings. I hate a phaser that sounds like you're at an airport when you stop playing.
Thanks again!
Mid build causality 6 and I cant see how to wire the regen pot since I'm using the parity switch.
Ahhhggg help.
meantime i'll trawl through the thread
thanks for any enlightenment
Rich
post deleted still no joy
Quote from: Kipper4 on April 08, 2015, 02:12:19 PM
Mid build causality 6 and I cant see how to wire the regen pot since I'm using the parity switch.
It's in there somewhere, mate. I have a local copy of the C6 board and wiring diagram. Either side of the parity switch (odd and even) go to the pads in the bottom left (if you're using Rick's board). The common terminal of that switch goes to Regen 3. The only other Regen connection appears to be to lug 2, and it comes off the bottom of R40 in the middle of the board (which is a 10K).
Edit: it's here (http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg737547#msg737547).
Edit #2: watch out for Rick's caveats on p16 (http://www.diystompboxes.com/smfforum/index.php?topic=80456.msg786033#msg786033)!
Thanks Marc
Good catch.
Now for the will it won't it phase.
Did you see what I did there ::)
Cheers
Don't give up the day job, Rich. :D
So maybe unbook my half hour slot at the comedy store then.
Well that was fun debugging and I'm not done yet.
I might have to implement the Vref using 78l05
Another afternoon debugging and i'm no nearer. frustrated now
Rant over
C6
I've been over everything with the meter to check continuaty.
I've checked the lfo output with the scope.
one sub instead of TL084 im using TL074
I'm at my wits end after another evenings debugging. it's 2.30 am
I've just done the 78L05 cludge. I'm off to bed.
I'll check if it has worked in the morning.
Otherwise expect a new thread entitled debugging the C6.
Night John boy...zzzzzzzzz
I take that back my lfo isnt lfo'ing.
plus im getting guitar signal on it at lfo output......
The fecker is now.
I had a solder bridge on the lfo output.
Now i can get back to the parity switch mod an phase/filter switch mod.
Thanks for letting me vent.
I'm really not one to relight old threads but I feel I should here;
I'd really like a many-stage LM13700 phaser I could wrap my head around and this fits the bill! Ever since I heard the deep-long swoosh of a Moog MF-103 I've been dying for an over the top phaser. I understand this is far from a Moog project but would anyone have any recommendations to make this compete with the MF-103?
I've been looking at the Causality 6 schematic and would like to triple the stages (how much is too much? :icon_lol:) Though I'm a little confused to why the names like "Causality 4" seems to have 2 phase stages and the Causality 6 has 4. Is the name not relevant to the amount of stages or am I wrong here?
I see a few mods here that would be very ideal for this project but I'd still like some intel from the forum.
Has anyone here adapted this project beyond 4 stages (Causality 6)?
The number of stages that can add value to a phaser depends on what you're feeding it, and what you're listening to it through. The same thing goes for the comb filtering of a flanger.
The challenge is that, much like a tree falling in the forest with no one around to hear it, a notch inserted to a frequency-band that the instrument/source does not produce, or listened to with a speaker that does not possess the requisite bandwidth, fails to impress.
Having listened to white noise processed with a 24-stage phase-shifter, I can vouch that, yes, highly complex wide-bandwidth signals CAN sound staggering through yet more stages. But, as many guitar players can attest, the flanger they spent good money on doesn't sound anywhere near as dramatic as the recording that inspired them to buy it...when they simply play their guitar through it...because the guitar lacks the bandwidth that the mixed-down multi-source recording that inspired them had.
I find that, for guitar, more than 8 stages tends to be moot. Yes, I know there is a plethora of phasers with 10 and 12 stages. I have a Boss RPH-10 with 12 stages...but a guitar through a guitar amp makes those top two notches inaudible. A synth played through wide-bandwidth speakers will display an audible impact of those top two notches, because both the synth and the speakers have the requisite bandwidth.
BUt, but, but flangers have a lot more than a mere 4 notches, you say. And you are correct. So why can I hear a lot more than 4 notches in a flanger, but not in a phaser? Simple; they are spaced farther apart in a phaser, and the lowest notches a flanger produces are much closer together than those produced by a phaser, as well as the higher notches produces in that very same flanger.
Personally, I find that 6 stages is pretty much the sweet spot for guitars. It is a complex-enough change, plus the feedback path causes fewer problems, and the location of the notches is less problematic. Adding more stages lowers the frequency range where the notches (and adjacent peaks) are located, rather than simply adding one more notch above where your current highest one is, and leaving the other notches where they are. As well, one assumes that each phase-shift stage is unity gain. But even using 1% resistors, there is still a chance that, when all the phase-shift stages are added up, the entire path has a gain greater than 1x. And when that happens, feedback/resonance has to be turned down so that oscillation doesn't occur.
Now, both problems CAN be fixed by: a) changing the value of the caps to nudge the range up a little and keep the woofiness out, and b) using a trimpot to dial back the resonance/feedback so that you can safely turn the feedback up full tilt without fear of setting off the siren, and c) sticking a small-value cap in the feedback loop of one of the phase-shift stages to tame any accumulated noise.
In the process of trying to finish up some pedals that had been sitting on the bench for too long.
One of them was a Causality 4 MkII that made the most obnoxious thumping sound. I used an LM358 for the LFO, so I thought it couldn't be that. I had also used an LM324 for the 4 audio stages.
Reasoning that the 324 might not be able to handle something about the circuit, I swapped it out this evening for a TL054 quad op-amp (the schematic indicates a TL084, but this was close enough, and I got a good deal on them). Problem solved!
It still provides a nasty thump if one dimes the width and range controls, but you're not supposed to do that anyway. It was easy to get a nice thump-free sweep by using those two controls judiciously.
Quote from: Mark Hammer on March 09, 2016, 07:54:53 PM
In the process of trying to finish up some pedals that had been sitting on the bench for too long.
One of them was a Causality 4 MkII that made the most obnoxious thumping sound. I used an LM358 for the LFO, so I thought it couldn't be that. I had also used an LM324 for the 4 audio stages.
Reasoning that the 324 might not be able to handle something about the circuit, I swapped it out this evening for a TL054 quad op-amp (the schematic indicates a TL084, but this was close enough, and I got a good deal on them). Problem solved!
It still provides a nasty thump if one dimes the width and range controls, but you're not supposed to do that anyway. It was easy to get a nice thump-free sweep by using those two controls judiciously.
I've just tried to breadboard the Causality 4 using 22k instead of the 27k and 1k5 instead of 1k8. But there seems to be a error in the nest...
I used an lm358 for the lfo and a TL074 for the audio path, was tempted to used a lm324 there lol.... I'll try again - I think I have a TL084 kickin' around somewhere I'll swap that if the 74 doesn't cut it.
Do you think my resistor substitutions would be a problem? Also thank you very much for the intel! Great info.
I'm trying to choose the right schematic loaded with additional features and I see this one (https://dl.dropboxusercontent.com/u/967492/Causality%206%20Phaser%20Rev%202.JPG)
Why is Rev10 -normal Causality 6 from 2009 and Rev2 -with additional functions from 2010?.... These revision names are confusing. I wouldn't want to build something from an obsolete schematic.
Also I've heard many times any more than 6 phase stages is not audible with guitar so I guess I'll do 6 and not 12 :icon_lol:
I may need to start a new thread here but I'm wondering how important it is to have the 47k and 470k pots? I'm having trouble finding them without spending a ton on shipping and they are not the most typical pot values. Also, any issue with getting a 500v capable ceramic disk in for the 10nF cap?
Using this layout by the way (http://tagboardeffects.blogspot.com/2012/02/causality-4-mkii-rick-holt.html) and have everything soldered up on the board and only missing the 10nF ceramic disk. Need to solder on the pots and I/O and eager to put this one to bed. Thanks and please let me know if I should start a new thread.
pgorey-
You can use 50K and 500K pots in place of the 47K and 470K
The 10nF is just in the feedback loop of the LFO- you can use anything over 10V rating.
Quote from: pgorey on April 03, 2017, 11:11:27 PM
. . . and they are not the most typical pot values.
Perhaps not in North America, but quite common in Europe. Rick's a subject of Her Britannic Majesty and is domiciled in her realm. :)
Thanks for the feedback. I used those pots (50 and 500) and it sounds great! Love this design and the variety of sounds I can get from it. I installed a trim pot to dial in the bite of the regen / drive pot and it sounds phenomenal. Thanks again!
I use the causality 6. Great phaser.
I did mod it to remove the dry path on a switch though.
If I get a big enclosure free I should do an 8~12 stager.
If one plans to use it exclusively for guitar or bass, I wouldn't bother going past 8 stages. The additional notches produced by adding stages tend not to be audible.
The other advice I would add is limit the low end in the feedback path, and use a trimmer to prevent feedback resulting in oscillation. Phase shift stages are intended to be unity gain. But 5% resistors being what they are, a given stage can produce a smidgen of gain (e.g., 5% less on an input resistr and 5% more on a feedback resistor yieldsa stage gain of 1.1x). As one adds more stages, the risk of cumulative gain increases (e.g., 1.1 x 1.1 = 1.21), increasing the risk of oscillation
That increased risk of gain also increases the risk of noise. Phasers using 6 or more stages often include a feedback cap in one or two phase-shift stages to roll off accumulating treble. If a phase shift stage uses 10k input/feedback resistors, consider a 1nf-1n2 feedback cap in parallel with the 10k to roll off some top end while still maintaining the crispness.
Hey guys,
i tried this cool design, but couldn`t get it to work. The circuit works so far, but there is a massive volume drop, until I touch my finger on one specific point on the upper side of the board (view pictures). The volume then comes back until bypass-volume, like it`s supposed to be.
I have done a litle video, where you can see the strange behavior: https://youtu.be/izvq2eONoNY (https://youtu.be/izvq2eONoNY)
Does anybody have an idea how to solve this problem?
Many thanks for your help,
and best regards
Veit
(https://s17.postimg.org/3x7k4iybv/CPMKII_board_oben.jpg) (https://postimg.org/image/3x7k4iybv/)
(https://s7.postimg.org/vuroqlj9j/CPMKII_board_unten_M.jpg) (https://postimg.org/image/vuroqlj9j/)
Quote from: Kipper4 on May 25, 2017, 01:52:35 PM
I use the causality 6. Great phaser.
Small bump-ette to say that Rich was quite right. I (finally) got around to building one:
(http://www.bouron.org.uk/marc/C6-925.JPG)
(more snaps in the main Pictures thread (https://www.diystompboxes.com/smfforum/index.php?topic=36392.msg1162816#msg1162816))
I love it Mark! Very smart. Nice to know this design is still being built. I'm just about to retire the Eurorack version, as the advent of reissue/clones of CEM3320 (Alfa AS3320) means 4 stages are possible on one chip. With a charge pump these could be used in a pedal too I suppose. Alfa are also doing a 4 OTA variant of the LM13700 (AS13704) which is ripe for some phaser action, and should run on 9V. I've been been thinking a lot about phasers again recently.....
Why use up CEM3320 clones? Leave 'em for the synth gang. SSM2164 clones are cheap and available. And if a quad 13700 becomes available, so much the better.
Mike Irwin once demonstrated a phaser for me that used 2-pole allpass filter stages (most OTA-based phasers use 1-pole stages). Interestingly, the notches were closer together than what we're familiar with. Because of that, even without much feedback used, the sound is more "focussed" as the tighter cluster of notches moves around.
I think some sort of aperiodic sweep is desirable. That could be from 2 unsynced LFOs being mixed, or some other variation. Anything that removes the up-and-down-and-up-and-down monotony makes the effect something you don't mind leaving on. Of course, there are times when you want the sweep to sync with something pertaining to the flow of a tune, so I guess the "periodic option" is still worth retaining.
Thanks Rick. I have one more phaser of yours in the pipeline... ;)
Quote from: frequencycentral on September 16, 2019, 04:53:23 PM
I've been been thinking a lot about phasers again recently.....
Of course! It's the law, right? ;D
P.S. I can post my vero layout if anyone's interested? I can't remember if there's one in this thread already (and is still online and not blurred).
(http://www.bouron.org.uk/marc/C6-930.JPG)
Did anyone try an Ensemble phasor - a similar idea as a Solina triple BBD chorus but with phasor stages?
Using an MCU, it would be possible to have tailored multi-phase LFO sweep waveforms that also supports tap tempo. For guitar, only dual-channel might suffice. I read somewhere that Donald Fagin liked to use a pair of Phase45's with his Rhodes piano for a fake stereo effect.
After a brief scan of a few pages of the thread, it seems like the old perf and pcb layouts are ph[otob]uck[et]ed. Are there any legible ones for late versions of the Causality family available?
There is a way to see the photobucketed pics but it's a pain. First right click and tell it to view image, then save the pic locally. The file can then be opened and will not have the blur or photobucket banner on it.
Hopefully with Rick's blessing, here's what I have in my stash for the Causality 4 and Causality 6 designs. (@Rick: let me know if you would prefer me to pull this post.)
original schematic, perf layout and PCB:
(https://i.imgur.com/UAxXE4z.jpg) (https://i.imgur.com/QUvRSGv.gif) (https://i.imgur.com/XsUeeXt.gif) (https://i.imgur.com/4YmXeBh.gif) (https://i.imgur.com/yW3oqm8.gif)
Mk. II schematics and PCB:
(https://i.imgur.com/QizwG7s.jpg) (https://i.imgur.com/xldWEaC.gif) (https://i.imgur.com/4SfBk5F.gif)
LED wax'n'wane mod:
(https://i.imgur.com/ua5HNTW.jpg)
daughterboard for extra stages:
(https://i.imgur.com/y7MYsF2.gif) (https://i.imgur.com/2s6mEa0.gif)
Mk. II V2:
(https://i.imgur.com/OpnqzQZ.gif) (https://i.imgur.com/HFI7dYQ.gif)
Causality 6 schematics, original and rev. 2:
(https://i.imgur.com/45tGEG4.jpg) (https://i.imgur.com/mICN97V.jpg)
And here's the slightly simplified C6 version I built along with my vero layout:
(https://i.imgur.com/bmniBt8.jpg) (https://i.imgur.com/LDZpHim.png)
Thanks for posting these! I've been looking for them for a while. I have the old layouts but no schematics to go with them.
Quote from: frequencycentral on September 16, 2019, 04:53:23 PMAlfa are also doing a 4 OTA variant of the LM13700 (AS13704) which is ripe for some phaser action, and should run on 9V. I've been been thinking a lot about phasers again recently.....
That's a fine idea ::)
And some motivation to give SMD work a try.
I recently gave away my CA3094 Small Stone clone so I've been itching for another OTA phaser.
-KM
Note that OTA-based phasers permit the wonderful phase-filter mod. Flip one end of the cap in a stage from the input to ground, and the stage converts from allpass to lowpass. See the SSM2040 appnotes or issue 4 of DEVICE, that I posted on my old Ampage site ( http://hammer.ampage.org/files/Device1-4.PDF ).
Thanks, Marc (& Mark).
Quote from: bluebunny on September 17, 2019, 12:28:52 PM
Hopefully with Rick's blessing, here's what I have in my stash for the Causality 4 and Causality 6 designs.
Thank you very much.
Tayda just got LM13700's back in stock. Coincidence? I think not!
How does the Causality phaser differ from the Maestro phaser soundwise? Do they have a lot in common? Both are OTA based and both have the resonance fed back from the 5. stage..
How to discribe the difference from sweeping stages to fixed ones? The Maesto 5 stager sounds great but would it benefit from 2 extra fixed stages on the front and back like the Causality offers?
Probably someone already discribed it but I can't find it in detail..
Quote from: frequencycentral on September 16, 2019, 04:53:23 PM
I love it Mark! Very smart. Nice to know this design is still being built. I'm just about to retire the Eurorack version, as the advent of reissue/clones of CEM3320 (Alfa AS3320) means 4 stages are possible on one chip. With a charge pump these could be used in a pedal too I suppose. Alfa are also doing a 4 OTA variant of the LM13700 (AS13704) which is ripe for some phaser action, and should run on 9V. I've been been thinking a lot about phasers again recently.....
I breadboarded a 3320 phaser up a few months back, I found that if you're using the full sweep capability (which is a big part of the appeal) as it sweeps so high they get pretty noisy for guitar use, the S/N specs are about as bad as a BBD so the space benefits of 4 stages on a chip quickly disappeared with the charge pump and additional support circuitry.
Quote from: Scruffie on September 19, 2019, 08:09:36 AM
Quote from: frequencycentral on September 16, 2019, 04:53:23 PM
I love it Mark! Very smart. Nice to know this design is still being built. I'm just about to retire the Eurorack version, as the advent of reissue/clones of CEM3320 (Alfa AS3320) means 4 stages are possible on one chip. With a charge pump these could be used in a pedal too I suppose. Alfa are also doing a 4 OTA variant of the LM13700 (AS13704) which is ripe for some phaser action, and should run on 9V. I've been been thinking a lot about phasers again recently.....
I breadboarded a 3320 phaser up a few months back, I found that if you're using the full sweep capability (which is a big part of the appeal) as it sweeps so high they get pretty noisy for guitar use, the S/N specs are about as bad as a BBD so the space benefits of 4 stages on a chip quickly disappeared with the charge pump and additional support circuitry.
Maybe that's why the Boss PH-2 and RPH-10 both use companding. OTAs have gotten much better over the years, but they still aren't as intrinsically immune to noise and distortion as LDR-based phasers.
Quote from: Mark Hammer on September 19, 2019, 09:10:51 AM
Quote from: Scruffie on September 19, 2019, 08:09:36 AM
Quote from: frequencycentral on September 16, 2019, 04:53:23 PM
I love it Mark! Very smart. Nice to know this design is still being built. I'm just about to retire the Eurorack version, as the advent of reissue/clones of CEM3320 (Alfa AS3320) means 4 stages are possible on one chip. With a charge pump these could be used in a pedal too I suppose. Alfa are also doing a 4 OTA variant of the LM13700 (AS13704) which is ripe for some phaser action, and should run on 9V. I've been been thinking a lot about phasers again recently.....
I breadboarded a 3320 phaser up a few months back, I found that if you're using the full sweep capability (which is a big part of the appeal) as it sweeps so high they get pretty noisy for guitar use, the S/N specs are about as bad as a BBD so the space benefits of 4 stages on a chip quickly disappeared with the charge pump and additional support circuitry.
Maybe that's why the Boss PH-2 and RPH-10 both use companding. OTAs have gotten much better over the years, but they still aren't as intrinsically immune to noise and distortion as LDR-based phasers.
Even with companding and an emphasis network it still had more background noise than a small stone with the colour on.
Don't get me wrong, makes a nice phaser but I wouldn't call it a 1590B friendly chip.
Quote from: Mr. Lime on September 19, 2019, 07:29:42 AM
How does the Causality phaser differ from the Maestro phaser soundwise?
I don't have the adjectives to describe it, but they are quite different. I might venture that the Stage Fright is almost flanger-like, but not. (No helicopters.) And the C6 is very phaser-y. I'm not helping, am I? ;D If I were to mimic the Stage Fright vocally, my face would be comically contorted! :o
There are going to be a few things that make two phasers sound fairly different from each other, even though they might have very similar designs:
1) Component tolerances in the phase-shift stages This can affect how wide the sweep is, how focussed or diffuse it is, and where in the spectrum notches might occur.
2) Component tolerances in the modulation part. This can affect how wide it tells the allpass stages to sweep, where it tells them to start from, and the shape of the sweep.
Hi,
In 2015 I built a stripboard version of the Causality 4 Mk II using tagboardeffects layout here http://tagboardeffects.blogspot.com/2012/02/causality-4-mkii-rick-holt.html (http://tagboardeffects.blogspot.com/2012/02/causality-4-mkii-rick-holt.html) .
It suffered from very low output and I got busy on other stuff.
I just revisited it and discovered that if I touch anything metal (screwdriver, tweezers etc.) to pin 12 of the IC2 TL074 (or TL084) the output becomes much louder, ie. "normal". Everything else seems to work. I tried a TL074 and a TL084 with the same result.
Can anyone suggest what to do next? TIA :)
FWIW I rebuilt the stripboard and now my phaser works. :)
Good news. I'm guessing from your "touch-it-and-it-works" description that you may have had a dry joint?
Yes that's the most likely possibility. The original build was pretty dodgy, using two scraps of stripboard "joined" with tiewire.. definitely sub-optimal ::)
Hello,
I am building the Causality 4 Phaser MkII from this veroboard layout (http://tagboardeffects.blogspot.com/2012/02/causality-4-mkii-rick-holt.html). Everything is going well so far, except that i just noticed that the 10nF capacitor is display in yellow, like a ceramic capacitor.
I have polyester and mylar 10nF caps, but no ceramics : is it important to use a ceramic cap, or can I just use any kind of capacitor, as long as it is 10nF?
Thank you !
[Edit] I checked TonePad layout, and the cap is the same than the other, so i think i have found my answer ;)
I think it was probably shown in that layout as a ceramic since it needs a 2.5mm pitch in that position. But anything you have to hand will do: it's in the LFO, not audio.
And besides, it's rock and roll, where cap quality doesn't often make any audible difference. If it was an analog synth VCO, where stability and precision mattered more, THEN you'd be right to ask about type. But for this particular circuit, rest easy.
Hi, Thank you.
I just finished the build : So far, it sounds great ! I love phasers, and this one is very versatile with a sound on its own and many options. It's great it can do slow sweeps, and it sounds quite "synthy".
However, something is wrong, because I get a weak sound (low volume, no bass), and the phaser goes wildly into self-oscillation (I don't mean the expected self oscillation when the regen is cranked).
I have used 13700, TL074, 5532, as advised, but i have read that Rick Holt had used TL084 : could it be that? I am still reading the thread, but there are 26 pages(!), and haven't found a mention about such an issue yet... I am also obviously double-checking my build, but would such symptoms sound familiar to you (low volume, cranked resonance)?
... and this is the kind of thing to expect when you forget to solder one chip socket's pin :icon_redface: :icon_lol:
After close inspection (and one soldering on the missing pin), everything works as expected now, and I like this phaser a lot : thank you Rick/Frequency Central !
Result! :D
If you like the C4, you might also enjoy the C6. 8)
Ah ah !
For now, I think 4 stages will be enough. I often like softer phasers (2 stages), and 4 stages is creamy enough to my needs most of the times.
... But now that i know how great Causality4 sounds, who knows, I might be tempted at some point ;)
Aaaaaand another one. Just breaded it, love this thing. Will try with the new TapLFO during the next days. Looking to somehow incorporate the Vibe/Whirl/Swirl trick from Tri-Vibe (ROG), though, instead of the "regen" pot. Maybe put it from buffer output pin to output pin of the last phase shifter.
holy cow, the whole enchilada!
i sent mine to steve hunter over in espana, so i need to rebuild myself another.
there's also a brilliant verified layout(s) on tagboard effects for this, with some other mods.
Quote from: pinkjimiphoton on March 03, 2021, 02:30:06 PM
holy cow, the whole enchilada!
i sent mine to steve hunter over in espana, so i need to rebuild myself another.
there's also a brilliant verified layout(s) on tagboard effects for this, with some other mods.
Good one, will have a look. I have the ambition to make all my PCBs myself - got the photo positive etching stuff, maybe it's time I tried a double sided one for once. Heh, this will be a hectic thing between expose top and bottom side and quite a sprint to the developer bath :D
Just added the "Width" pot from Mk. II to my Mk. I Causality 4 bread. Now the sweep is much stronger than before. Nice!
I see that probably the biggest difference between Causality and Tri-Vibe is that the former doesn't utilize the LM13700's "Diode Bias" pins (2 and 15). "Instead" there's this 1k8 resistance 'tween the internal diff amps positive and negative inputs. If I now go and connect the diode pins to V+ with some resistance in series AND rip out the resistor between pos. and neg- op-amp inputs and put them to Vref via small resistors (470R @ Tri-Vibe), what will happen from a theoretical point of view? Since the LFO's output connects to pins 1 and 16, which are "Bias Inputs" AND the pos. and neg. amp's input are connected to V+, Diode Bias connected to Vref halfway between V+ and GND, what does that mean for effectivity?
QuoteAND the pos. and neg. amp's input are connected to V+
V+ or Vref?
QuoteSince the LFO's output connects to pins 1 and 16, which are "Bias Inputs"
I think I'm misunderstanding you, but in case I'm not, those pins, 1 and 16, "I
ABC", though labeled "bias" are the voltage/current control pins, they don't have anything to do with biasing inputs so AC can ride on DC, like what we do for single supply designs in guitar pedal world.
> ...those pins, 1 and 16, "IABC", though labeled "bias" are the voltage/current control pins, they don't have anything to do with biasing inputs so AC can ride on DC, like what we do for single supply designs in guitar pedal world.
Iabc really does set the idle current, a traditional function of "bias".
As you say it does not affect the in and out DC voltages, so it is unlike most of our usual circuits.
Long time no post.
Is there a schematic with designators anywhere for this? The OP mentions R5, C7 etc throughout this post but the schematic only has values so it's impossible to know which is which.
Any leads after all this time?
EDIT: also, pot lug numbers should be mandatory on all schematics. I have a chronic fear some of my pots will be backwards.
I presume those designators refer to Rick's PCB/perf layout. Without looking back over the thread, I'm guessing they may have disappeared...
Edit: Take a look at page 2.
Edit #2: Take a look at page 23. A while back I re-posted all the schematics and layouts from this thread that I have in my stash.
Is anyone offering a pcb for the mkII? It seemed like GuitarPCB did for a while but my query never got a response. Maybe someone on the forum can do single order fabs?
I'm pretty certain I built a C4 a long time ago using a board from Rick. You might PM him to see if he has any lying around in the bottom of a drawer?
Quote from: FootSolder on October 20, 2022, 08:42:08 AM
Is anyone offering a pcb for the mkII? It seemed like GuitarPCB did for a while but my query never got a response. Maybe someone on the forum can do single order fabs?
I'm working on one now, I'm just worried the pots might be backwards. It'll be for a 1590bb size.
Always late to the party!
Built my lovely C4...except Vbias/Vref is WAY off. 1.8-2v
I've spent hours pouring over this thing and just can't figure it.
The 47k out of pin 14 on the 13700... where is that in the schematic? Pin 14 side, it's 1.8v; Width3 side it's 4.7-5.0v, which is funnily enough where I'd be happy with Vbias being...
Thanks in advance...
Will
Hi and Welcome.. :icon_wink:
Quote from: Will_em_all on February 28, 2024, 08:24:30 AMBuilt my lovely C4...except Vbias/Vref is WAY off. 1.8-2v
There are two obvious reasons:
1. Wrong Vref resistive voltage divider values ratio..
2. Too much current drawn through divider upper resistor..
Quote from: Will_em_all on February 28, 2024, 08:24:30 AMThe 47k out of pin 14 on the 13700... where is that in the schematic?
Do you refer on the schematic below..?
(https://i.imgur.com/QupI6WV.png)
I think it might be this one, since Will mentioned a "Width" pot:
(https://i.imgur.com/QizwG7s.jpg)
Thanks Antonis, Marc,
Yes, it's the mkII with the Width pot.
Quote from: antonis on February 28, 2024, 08:48:30 AMhere are two obvious reasons:
1. Wrong Vref resistive voltage divider values ratio..
2. Too much current drawn through divider upper resistor..
No 1. was my first guess, but I can't find anything that appears to be pulling it down. I originally had the 100k trimmer mod between Vbias and pin 6 of the TL084, but went back to standard to remove as many variables as I can.
With the trimmer at its highest resistance I could get the voltages at the TL084 and 13700 closer, but still not in range, and I presume not operating correctly.
No 2. I've not considered... would a killer blue LED possibly do something like that? I've also got the Speed LED 2 (see vero layout on p.23) which gently increases in brightness with the first LFO cycle, but then never dims...
Quote from: Will_em_all on February 28, 2024, 10:54:15 AMwould a killer blue LED possibly do something like that?
No..
(at least, not without dipping +9V also..)
Quote from: Will_em_all on February 28, 2024, 10:54:15 AMI've also got the Speed LED 2 (see vero layout on p.23) which gently increases in brightness with the first LFO cycle, but then never dims...
That calls for a permanently "high" LFO output..
(unsurprising 'due to different DC bias levels between inverting and non-inverting inputs..)
(https://i.imgur.com/lpa0PQH.jpg)
Quote from: antonis on February 28, 2024, 02:07:01 PMThat calls for a permanently "high" LFO output..
(unsurprising 'due to different DC bias levels between inverting and non-inverting inputs..)
Yes, that does make sense for the LED behaviour.
Guess I'll triple check the voltage divider values. I've also had a fudged-1M linear pot in for Speed, but can now switch that out for the correct reverse log. Not sure that would affect anything, but who knows at this point! ::)
First of all, fix that low Vref issue..!! :icon_wink:
Unless, of course, your DMM has a very low impedance hence those "faulse" readings doesn't correspond to reality..)
Could you post some pics of your build..??
(items and solder sides..)
Not sure if these work...
Be kind :icon_biggrin: I know they're rough! When I started it, I couldn't find my 'good' solder! Like doing surgery with a hammer.
(https://i.postimg.cc/cvG646h4/IMG-3547.jpg) (https://postimg.cc/cvG646h4)
(https://i.postimg.cc/vgKZRmDy/IMG-3548.jpg) (https://postimg.cc/vgKZRmDy)
(https://i.postimg.cc/BLbnwFSN/IMG-3549.jpg) (https://postimg.cc/BLbnwFSN)
(https://i.postimg.cc/7JTYqyT2/IMG-3550.jpg) (https://postimg.cc/7JTYqyT2)
RED frame -> WARNING
GREEN frame -> CAUTION
(https://i.imgur.com/v0leotM.jpg)
Thanks!
Top right is fine, that's pin 1+2 of my trim pot - that I've taken out for now.
I'll check over the others again :icon_eek: