Hi all,
Since DIY stompboxes has a pretty far reach, with members spread out around the world, I thought I'd give this a shot!
On a few different sites one will find the schematics, PCB and component layouts that were scanned from a Japanese DIY stompbox book. Looking at the info available for the Multi-Flanger, it seems as if there is at least one page (in Japanese) missing that would explain the many trimpots and calibration.
Also, on the schematic there is mention of a Feedback (regeneration option circuit) that's not depicted anywhere on the two available sheets.
My question is: Does anyone in this great big Stompbox building land have the original book or the missing information? Being from Southern California, I'm a bit rusty on the Japanese I learned in the third grade, but I know a few people that would be willing to help me out.
I'd like to build this beast and any additional info would save alot of time.
Thanks,
Larry
Quote from: armdnrdy on May 24, 2012, 03:38:51 PM...On a few different sites one will find the schematics...
A link would be welcome for googlazy ppl like me :icon_mrgreen:
Quote from: armdnrdy on May 24, 2012, 03:38:51 PMas if there is at least one page (in Japanese) missing that would explain the many trimpots and calibration
flanger's trimmers setting is usually more or less the same, despite schematic or brand name.
Post a schematic and we may help...
I certainly wish I had the rest of the documentation for it.
As near as I can tell, the output of the delay path is at pin 7 of IC3b. That gets fed to pins 2 and 6 of IC6 (mixing stages) via a pair of 100k resistors. That node linking pin 7 and the two resistors, is the point where one would normally tap the delay path to feed back to the input+delay mixing node in a flanger, and which is indicated by the pair of open dots with the japanese writing above it and the arrow pointing to it.
I would imagine the feedback path would need to be something like what we normally see, like a cap, a pot, and another cap, to mix in varying amounts of delay feedback to that first filter stages after the input gain-set stage.
http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/multi-flanger.gif.html?g2_imageViewsIndex=1 (http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/multi-flanger.gif.html?g2_imageViewsIndex=1)
Here's the schematic. As you can see it's not a normal flanger! I count 12 control pots and 7 trim pots!
Hey Mark,
I agree, I've been looking at flanger feedback circuits with similar entry and exit points to get a better idea of what it needs. It looks pretty general. A cap, feedback resistor, feedback trimpot, and a feedback control pot.
at a very first glimpse:
VR6 is BBD's null
VR5 is BBD's bias
VR4 set the peak level, rise signal to BBD until clips, similar stuff was usually trimmed 3dB BEFORE clipping
VR3 will center Envelope's range, shouldn't be difficult to set when you listen for both uppest adn lowest flanging points
VR2 should set the "higher" flanging point (lowest delay) when in TRIGGER mode
VR1 will center LFO's range (check ADA Flanger T3 setting)
VR7 will set the lowest delay.
Thanks Fender3D,
That info helps quite a bit. I know how to identify and calibrate trimpots in a "normal" flanger, but I've never encountered some of the features that are included in this design. I think that the additional features are what attracted me to take a stab at this build.
PS: Thanks again for helping me through my first (MXR) flanger build last year.
You're welcome,
those features might be a nice plug-in for phasers and flangers and maybe VCFs...
hmm ADA Flanger has VC input... (and Manual control is indeed a VC, ... almost all flangers involved) :icon_twisted:
... breadboarding time anyone?
If you attempt it (and I have a toner transfer pattern for it just waiting for the opportunity), note that an MN3009 will be tricky to get hold of. An MN3007 CAN be substituted, pin-for-pin, but will quadruple the delay time, pushing it well out of decent flanging territory.
Now, normally, my patent reply would be to say "...but you can just look for the relevant clock cap, and reduce its value to up the sampling frequency, thereby producing less delay time". But look at that lower right hand corner, and you'll see a timing cap of 5pf there. Moreover, squeezing out a higher clock rate from the chip than normal would almost certainly require buffering of the clock lines to the BBD, for which there is clearly no allowance on the board.
If you can find an MN3009, more power to ya, but in the absence of one, I'd leave this as an idea rather than a project you're committed to.
Hey Mark,
I already have two MN3009s and a couple of 2SA798s, so that should take care of the hard to get componants unless you want to include the dual 50KB center tapped pot!
I have plans worked out to modify a dual 50KB with silver conductive paint, copper tape, 5 minute epoxy and a small length of 24 gauge wire. (I'll let you know how that turns out)
On the subject of that pot, I was looking at that part of the circuit trying to figure out exactly what the dual pot is doing. It looks like a blend circuit but I don't what it's blending. It looks like maybe between effect outputs? Stereo Panning?
TWO 3009s? :icon_eek: Did I ever tell you you're my bestest friend? :icon_lol: If you have a chance to do so, pop an MN3007 out of a chorus and stick the 3009 in just to hear the difference.
The diagram IS drawn in a manner that makes it cumbersome to intuit the signal flow and how the controls work. Since there is no inversion in either of the two output/mixer stages, and there is no point in having two such output stages if they both provide the same signal, I am thinking the dual-ganged 50k pot does one of two things: ether it adjusts wet-dry balance such that one output contains more and the other less, or it provides the wet/dry signal inversion to produce sum and difference.signal
^^
It is a strange way to provide phase inversion
When pot is in center position, you got wet signal only;
full CW or CCW, you have dry signal inverted on one output and normal on the other (and vice versa)
Well, however weird they do it, I will say that, having both triggered-transient-generator sweep, and envelope-controlled sweep on my Tone Core Liqui-Flange, I have naught but good things to say about any flanger design, analog or digital, that includes those options, which this one does.
Mark,
So, the two outputs inverted from each other....faux stereo effect? creating the illusion of separation?
Also, I understand what most of the controls are: LFO Pitch=Rate, Form=wave form, ect, ect.
But the two I'm a bit unsure about are: EF. Sens (is it envelope follower sensitivity?) and INV SENS. (no clue)
About the PCB pattern, I pulled that off of you site ( Ampage, link at upper left of this page for others reading this) about a year ago and have been pondering a build ever since.
There's a few problems with the original pattern that I was going to fix. I was planning to add an on board, regulated LT1054 bipolar power supply, rework a bit of the routing to relocate jumpers that run under ICs, and add the pads for the regeneration circuit. (I've followed and labeled all of the controls back to the number designations and there's no provision for the feedback circuit. The arrow with the Japanese writing above it points to a jumper on the board that has to be installed and has no place for the feed of the regen. unless one wants to stuff two wires in one pad.
Quote from: armdnrdy on May 25, 2012, 12:45:58 PM
But the two I'm a bit unsure about are: EF. Sens (is it envelope follower sensitivity?) and INV SENS. (no clue)
They set the CV amount from the Envelope follower inv is... inverted (look at it as at up and down control on other EFs)
Mark,
I found one MN3009 on a strange BIK rack unit...
I posted pictures on the other site, please drop me a line if you know anything about it...
INV Sens should probably be labelled Modulation Amount. There is a contro for setting the modulation amount for the envelope, and for the transient/AR generator. The design provides for inverted sweep of each kind, but when it comes to downward sweep, it is not simply the mathematical "opposite" of upward.
So, you'll see VR3 which adjusts a voltage bias from which the envelope or transient will be subtracted. How much it should be subtracted is determined by INV SENS, such that all possible modulation sources (LFO, envelope+/-, AR+/-) at the mixing node of IC8a (Where the 4x100k resistors meet) provided the desired amount of sweep.
I have a dysfunctional Roland J106 in the basement that I picked up for $50 several years back. It has been a perennial head-scratcher as to whether I cannibalize it for parts (it contains a pair on MN3009s and MN3101s, among other things), or get it fixed. Everytime I'm ready to get it fixed, I see something that could make excellent use of the parts, and everytime I'm ready to rip it up, I see someone extolling the virtues of an intact J106.
Mark,
I'd say that if the MN3009 is socketed....cannibalize!!...or better yet, just call it borrowing...
Okay....with the addition of the dual 50KB center tapped pot to my parts collection...that completes the acquisition of the "hard to find" components for this build.
I've now bumped this project up a few notches, and would like to begin routing the board.
I've redrawn the schematic and made a few changes, and have a few other changes in mind:
(https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%20II.jpg)
Better PDF copy:
https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%20II.pdf
I added a footswitch (SW2) to choose between straight flanger and Envelope/Triggered flanger.
I added an "Attack" control (P14) who's placement was "lifted" from an almost identical circuit.
I'll probably make P1 (Gain control) a trimmer and delete the "Peak Level" circuitry.
Added a 15VAC wall wart power supply. (straight from MFOS)
Added a "Regen" circuit from the Boss BF-1.
Let me make something perfectly clear......I know absolutely nothing about Envelope controlled effects! Complete neophyte here!
I was wondering if I would get any mileage out of making the Envelope/Trigger switch (SW1) a footswitch.
Also, I've been trying to wrap my head around the Envelope/Trigger circuit.
It seems that when the Envelope/Trigger switch (SW1) is in the Envelope position, the trigger, which includes the Attack and Release controls, is still connected to the mixing node (R47-R50) through the trigger sens. control. (P6)
My question is: are the Attack and Release controls still active when SW1 is in the Envelope position?
Interesting, and a lot of work done...
The Regen path you have - it looks like it's hitting the output of the first amp. Is that right? I would put a virtual earth mixer in there which, so long as it's only in the path to the BBD input, shouldn't harm overall phase.
Quote from: anotherjim on July 18, 2014, 03:47:36 PM
Interesting, and a lot of work done...
The Regen path you have - it looks like it's hitting the output of the first amp. Is that right? I would put a virtual earth mixer in there which, so long as it's only in the path to the BBD input, shouldn't harm overall phase.
I'm not really sure what you mean.
The original drawing had the regen. circuit input and output points marked on it. There are additional pages to these Japanese book projects that never made it to the net. I'm sure that the exact regen circuit that the circuit designer had in mind would have been on one of those missing pages. In lieu of missing info....all I did was fill in the blanks with "standard" regen circuit components.
(https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi%20Flanger%20original.jpg)
Dare I ask if the trigger levels follows input dynamics? :icon_idea:
Quote from: StephenGiles on July 18, 2014, 04:32:18 PM
Dare I ask if the trigger levels follows input dynamics? :icon_idea:
You wish!
Hey Stephen,
I never got around to bread boarding your circuit. That weekend turned upside down and I didn't get much of anything that I wanted to accomplish done! Never enough hours in the day...or days in the week! :icon_wink:
Output of IC1a and IC3b are effectively driving into each other via the regen path. You might get away with that if you put a resistor immediately after IC1a, otherwise I'd thought the low output impedance of IC1a is going to pull the regen signal - effectively gating it.
BBD paths usually have just under unity gain, this looks no different. So if you want Regen to hit feedback, you'll need some gain too.
So a simple 2 input inverting opamp mixer before the BBD input filter is what I'm suggesting - like your IC6b but with 47k as the Regen input resistor so it's got gain enough for feedback.
Okay,
I see and understand what you are getting at. I missed the no gain issue.
The original board layout (which leaves a bit to be desired) has an actual jumper (for no apparent reason) between IC1A and R5 (33K)
If the regen circuit were to connect to that point, it would just need a single pad. So...There must have been more going on than a standard regen circuit consisting of a pot, trimmer, and a couple of caps.
For the likes of me I do not understand why the designer would put every bell and whistle on this thing and leave the regen circuit as an "option". ???
Quote from: anotherjim on July 18, 2014, 04:48:36 PM
...You might get away with that if you put a resistor immediately after IC1a...
You may just connect the FB path @ R5/R6/C4 node...
But I think you'll need smaller value resistors for R74 and TR8...
Quote from: armdnrdy on July 18, 2014, 03:13:52 PM
I added a footswitch (SW2) to choose between straight flanger and Envelope/Triggered flanger....
Then shouldn't SW2 better select between ENV/TRIG mod and LFO (ala Mutron), (not just deactivate ENV/TRIG)?..
Quote from: armdnrdy on July 18, 2014, 03:13:52 PM
...It seems that when the Envelope/Trigger switch (SW1) is in the Envelope position, the trigger, which includes the Attack and Release controls, is still connected to the mixing node (R47-R50) through the trigger sens. control. (P6)
My question is: are the Attack and Release controls still active when SW1 is in the Envelope position?
They are...
Just notice that P6 and P7 voltages are INVERTED each other, I guess it "might" work as ENV/TRIG's upper limit-lower limit, otherwise it "might" correct what Mark said about the envelope control:
Quote from: Mark Hammer on May 25, 2012, 01:08:14 PM
...when it comes to downward sweep, it is not simply the mathematical "opposite" of upward...
BTW
is R39 strictly necessary?
Think kindly of the designer. They may have wanted to keep options open with the Regen until a later stage of development.
The easiest and most common way is to blend regen with the incoming clean signal with some kind of mixer. That usually needs an inverting opamp for a decent virtual earth mixing circuit. That will also give an opportunity to add in some more low pass filtering which could be handy if there's still some clock noise making it's way to the delay output - and you wouldn't want to regenerate that.
It could also provide an opportunity to insert companding noise reduction, if it was found necessary, or maybe just a soft clip limiter to tame the howl at feedback.
Hey Federico,
Thanks for the input!
Quote from: Fender3D on July 19, 2014, 08:24:10 AM
You may just connect the FB path @ R5/R6/C4 node...
But I think you'll need smaller value resistors for R74 and TR8...
I agree with Jim. I think that it would be wise to add an op amp with gain and dial it back with the regen trimmer. In every circuit that I've looked at for reference, the feedback section is taken from a point with gain.
Quote from: armdnrdy on July 18, 2014, 03:13:52 PM
I added a footswitch (SW2) to choose between straight flanger and Envelope/Triggered flanger....
Quote from: Fender3D on July 19, 2014, 08:24:10 AM
Then shouldn't SW2 better select between ENV/TRIG mod and LFO (ala Mutron), (not just deactivate ENV/TRIG)?..
I think that the envelope CV reacts with the LFO to create a certain effect...
but...You got me thinking to switch between straight flanger and Envelope/Triggered flanger with a footswitch, and add a toggle switch to cut or add the LFO when the footswitch is in the Envelope/Triggered flanger position. That configuration will give three options, with two available on a footswitch.
Quote from: Fender3D on July 19, 2014, 08:24:10 AM
Just notice that P6 and P7 voltages are INVERTED each other, I guess it "might" work as ENV/TRIG's upper limit-lower limit, otherwise it "might" correct what Mark said about the envelope control:
I looked up "envelope invert" on the net and read that some ADSRs come with the ability to invert the wave shape. I think that when the trigger or envelope is passed through IC7B the wave shape is inverted for a different effect. When P7 is CCW, the wave passes through the 100K mixing node. (R47-R49) When P7 is CW, the wave is inverted. The original name for P7 on the original drawing is Inv. Sens (Invert sensitivity) Does this sound correct?
Quote from: Fender3D on July 19, 2014, 08:24:10 AM
BTW
is R39 strictly necessary?
R39 in parallel with P3 looks kind of redundant when P3 is CCW but, it might serve some purpose when P3 is CW.
P3 is connected to the input signal via R35 & R17, to IC 5 non inverting input, and to the mixing node. (R47-R49)
It's hard for me to tell if it serves a purpose. ???
I double checked the original board layout....and that's how it is all connected.
Quote from: anotherjim on July 19, 2014, 08:31:36 AM
Think kindly of the designer. They may have wanted to keep options open with the Regen until a later stage of development.
This doesn't seem like a work in progress....it was published in a Japanese Effector book back in the eighties. No disrespect to the designer.....I think that this is an intriguing design. Did you design this Jim? If so...I apologize! ;D
I was busy with business related matters for most of the day. I'll add an inverting mixer for the regen circuit and repost the schematic.
I appreciate your ideas and feedback. You've been very helpful.
Hah! No, wasn't me. That modulation section alone would have put me in the funny farm ;D
Here is a quick preliminary revision with the regen input mixer and a few op amps moved around. The op amps will find a final location while routing the board.
With this mixing configuration it seems as if the regen gain will change with the adjustment of the regen trim (TR8)
Is this correct?
If that is the case, I'm wondering if it wouldn't be better to connect the regen gain op amp (IC4B) at the output of IC3B.
(https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%20regen.jpg)
I just had another thought...
What if the regen circuit were connected as I originally had it (drawing on first page of this thread) and added gain to IC3B then lowered the gain resistors in the two output op amps? (IC6A & IC6B)
If this will work with no unintended consequences...this would be the easiest solution.
C'mon Larry...
R74 AND R78?
The only potential issue (but it might be as well a feature) is the feedback Phase inversion...
Quote from: armdnrdy on July 21, 2014, 12:32:48 PM
I just had another thought...
What if the regen circuit were connected as I originally had it (drawing on first page of this thread) and added gain to IC3B then lowered the gain resistors in the two output op amps? (IC6A & IC6B)
If this will work with no unintended consequences...this would be the easiest solution.
+1
I'd try that way, , first...
It will save 1 op-amp (and 2 resistors if you listen to me :icon_mrgreen: )
Quote from: Fender3D on July 21, 2014, 12:53:21 PM
C'mon Larry...
R74 AND R78?
I know, I know! ;D That's why I'm here....to learn! I just cut around what I originally had and was waiting for you to reprimand me! :icon_wink:
Quote from: armdnrdy on July 21, 2014, 12:32:48 PM
I just had another thought...
What if the regen circuit were connected as I originally had it (drawing on first page of this thread) and added gain to IC3B then lowered the gain resistors in the two output op amps? (IC6A & IC6B)
Quote from: Fender3D on July 21, 2014, 12:53:21 PM
+1
I'd try that way, , first...
It will save 1 op-amp (and 2 resistors if you listen to me :icon_mrgreen: )
This configuration is similar to standard regen circuits that I've referenced. The regen circuit is connected to an output with gain and then dropped in after the first op amp.
I'm going to say MK2 is just fine. But you don't need R74 (100k). I think the trim will be handy.
Input impedance - Do you want 47k? It could be 1M for direct guitar.
In mk1, you had regen feeding into the output of IC1a which isn't going to be nice - the incoming clean signal will gate the regen. You have to have a mixer.
Polarity inversion of the regen and incoming clean to the delay isn't a problem - the delay line is removing any fixed phase relationship. You only need to maintain true polarity of the dry signal path.
Regen source could be either of the post filter amps. It will probably "dull" out the regen faster from the last filter. Maybe a jumper option here so you can choose? There are designs that take regen before the post filter (from the BBD null), presumably depending on the pre-filter to clean it up. That could be another jumper option?
The Blend control isn't really a blend is it? It looks to me that it adjusts the dry level to a fake stereo anti-phase output, and you can switch phases turning the blend and dry off is at centre. There seems to be nothing to adjust the delay output level itself.
If you don't want the hassle of that 2 gang centre tap pot or can do without the fake stereo, you can save one opamp there. Ic4a as a unity gain inverter (needed to maintain dry path polarity) feeding a Dry output level control to IC6a and output of IC3b feeding a Delay level control to the other input of IC6a.
If it the intention to replicate the original design, then please ignore my ramblings ;) You could always leave room to attach a daughter board, fit jumpers for now as per original, and maybe the original "regen circuit" may come to light?
Hey Jim,
Thanks for the help.
I haven't got around to input impedance or pull downs yet. I usually redraw the schematic, make modifications, and then put on the finishing touches when I have something that is a bit more concrete.
I'm going back and forth with this regen circuit! As far as the original regen circuit coming to light....I have searched all over the net to find either the missing pages or a copy of the original Japanese book....no luck! What was scanned and posted on the net is all I can find.
I actually sourced the dual 50KB center tapped pot so....I was going to build that section per the original drawing.
I'll make some revisions and repost the "work in progress" drawing.
It seems like the original was meant for use with synth. I can imagine some fun could be had twiddling the blend control while holding a string pad chord.
Quote from: anotherjim on July 21, 2014, 04:37:52 PM
It seems like the original was meant for use with synth. I can imagine some fun could be had twiddling the blend control while holding a string pad chord.
Yes sir.
You can tell by the Gain control that I'm going to delete, the Peak level circuit that's already gone, and by the oversized (for guitar) caps in the signal path.
Here's the drawing getting a bit closer to being finalized.
(https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%20MK2.jpg)
Impossible to read drawing on my Blackberry! Won't focus for some reason.
Quote from: StephenGiles on July 22, 2014, 01:40:39 AM
Impossible to read drawing on my Blackberry! Won't focus for some reason.
Resized JPEG with reduced quality.
Try this PDF:
https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger.pdf
Quote from: armdnrdy on July 22, 2014, 02:37:51 AM
Quote from: StephenGiles on July 22, 2014, 01:40:39 AM
Impossible to read drawing on my Blackberry! Won't focus for some reason.
Resized JPEG with reduced quality.
Try this PDF:
https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger.pdf
Thanks Larry, much better on my PC - that is a superb drawing. I don't think mobile phones were made to read schematics!!
Last night I had the thought to delete the CV master control. This control might be useful if one had a free hand, (playing keys) but I don't see much use for it with guitar.
If I find that the different CV inputs are unbalanced, this can be dealt with by changing resistor values in the CV mixing node before IC8A.
I would imagine that all I have to do is delete the CV master (P8) and connect R54 directly to the output of IC8A.
I'd rather delete P12 (LFO depth) and leave CVMaster.
I guess it might be useful having a master for the complex voltage waveform, instead of setting 4 controls.
P8 will do the same work as P12 when using LFO
No,No,No....
I would rather be able to adjust each CV option separately to get different effects.
Remember that the different CVs get mixed at R47-R49....so with the separate adjustments come different settings with more sound options available.
I just don't see the reason for an "overall" CV depth adjustment.
Here is the latest revised drawing:
Here is a PDF for an easier read:
https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%207-25.pdf
(https://dl.dropboxusercontent.com/u/53299166/DIYstompboxes/Multi-Flanger%207-25.jpg)
I deleted the C.V. Master control, (sorry Federico ;D ) changed the Gain control (P1) to a trimmer, (will probably delete this trimmer once overall circuit gain requirement is established) added standard limiting diodes in the feedback loop of the mixing op amp, (IC4B)
Cleaned up and spread out the circuit to make it a bit more readable.
There are a few things that I noticed about this circuit while reviewing others flanger designs for reference.
The resistor values in the Sallen-Key lowpass BBD output filter. 150K? The standard value in everything that I reviewed is much lower, 10K-15K. (Panasonic data sheet MN3009 shows 33K-39K with higher value caps)
Another thing that I noticed is the lack of high frequency "roll off" caps in the feedback loops of the op amps in the signal path.
Any ideas?
Quote from: armdnrdy on July 25, 2014, 03:03:52 PM
...
I deleted the C.V. Master control, (sorry Federico ;D )
Hehe,
with all your changes and brainstorming this should be named now armdnflanging... :icon_mrgreen:
(and the former designer may only be proud about the guitar adapting)
my only concern was about having a complex mix of P3, P6 and P7 and the need for a "more-up" or "more-down" environment...
Moreover CVMaster allow you to play with Manual just lowering it, instead of the (carefully-mixed-before) 3 above (Morley enclosure time?)
Quote from: armdnrdy on July 25, 2014, 03:03:52 PM
...
added standard limiting diodes in the feedback loop of the mixing op amp, (IC4B)
Great, I think every flanger should have clipping-limiting diodes before BBD...
Quote from: armdnrdy on July 25, 2014, 03:03:52 PM
There are a few things that I noticed about this circuit while reviewing others flanger designs for reference.
The resistor values in the Sallen-Key lowpass BBD output filter. 150K? The standard value in everything that I reviewed is much lower, 10K-15K. (Panasonic data sheet MN3009 shows 33K-39K with higher value caps)
Another thing that I noticed is the lack of high frequency "roll off" caps in the feedback loops of the op amps in the signal path.
Any ideas?
Yeah, resistors have higher value, but capacitors are accordingly lower...
BTW
I'd rather prefer lower res/higher caps, 'cause in PCB you'll find lotsa pF adding to your tiny caps due to layout..
Again it's a good practice at least providing room for a roll off cap in op-amps feedback loop
uh oh
here's my scrooge heritage coming...
D18 and D19 may be saved for another pedal...
C28 and C29 should be 0.1uF and near regulators pins...
Thanks for the reply Federico.
Quote from: Fender3D on July 26, 2014, 09:36:42 AM
my only concern was about having a complex mix of P3, P6 and P7 and the need for a "more-up" or "more-down" environment...
I thought about that....what if each C.V. option is a different amplitude. If that is the case, I think that I would find a different "fix" to bring the C.V. options to the same level. I don't think that having to adjust the C.V. level is such a good idea for a guitar pedal...... Especially with the option that I've provided to switch between them "on the fly".
Quote from: Fender3D on July 26, 2014, 09:36:42 AM
I'd rather prefer lower res/higher caps, 'cause in PCB you'll find lotsa pF adding to your tiny caps due to layout..
Again it's a good practice at least providing room for a roll off cap in op-amps feedback loop
I may calculate the cut off frequency and adjust the resistors and caps accordingly.
I'll add 100pf ceramics to the feedback loops.
Quote from: Fender3D on July 26, 2014, 09:36:42 AM
D18 and D19 may be saved for another pedal...
C28 and C29 should be 0.1uF and near regulators pins...
I think your right about D18 & 19. I copied the PS from the Music from Outer Space site. The diodes are kind of redundant.
I'll meet you half way on the PS caps. Since this PS is starting out A.C. and is only half wave rectified, I'll keep the tants for their low ESR qualities, and add .1 caps for their high frequency qualities. There is no such thing as too much power supply filtering!
Deal? :icon_wink:
hmmm
Ok I can throw few pennies for 2 more caps indeed...
Now back to the breadboard you lazy kid...
:icon_mrgreen:
Quote from: Fender3D on July 26, 2014, 10:48:36 AM
hmmm
Ok I can throw few pennies for 2 more caps indeed...
Now back to the breadboard you lazy kid...
:icon_mrgreen:
Even though I despise bread boarding circuits this large....I decided the middle of last week...that's where this thing is headed! :icon_cry:
I just needed to bring a few ideas closer to "home" before I order parts that I don't have in stock.