I'm working on a nice pro double-sided PCB for the Echo Base, with the usual amenities of silk screen and soldermask. It's designed to fit in a BB enclosure, and so far it offers the following mods:
tap tempo for the delay using the PTAP
double time mod using a second PT2399
effects loop
modulation kill switch
feedback filter, to get filtered analogish repeats
oscillate momentary stomp switch
board mounted pots
mix pot
All of these are optional. You will be able to build a totally stock Echo Base with this board. Because of the physical limitations of a BB box, it won't be possible to fit all of these mods in a single build unless you were to step up to a larger box. For example, you just can't fit 3 stomp switches in a BB and have them really be usable, so you can't do both the tap tempo mod and the oscillation stomp switch in a BB (unless you made the byass a toggle switch). The tap tempo at this point only controls the delay time, which I know a couple of people will be bummed about. I just don't see tap tempo control over modulation to be universally wanted enough to warrant the extra size of the board.
As with the Gristleizer board, it has board mounted pots. This is to make what was before a massive amount of offboard wiring go a lot quicker, so this build will be much more leisurely and less prone to noise. But if you're into the wiring, or prefer a different pot layout than the board has, you can of course do offboard pots.
I'm running short on room, but are there any other features or mods you'd like to see incorporated?
Just a question about the effects loop - will that be for effecting the 'delayed' signal only? Could that loop be switchable - pre delay signal, delays only, post delay signal? I have no idea of if an on/on/on dpdt switch would handle this.
I would probably put this pedal in an 1790ns personally. A DD would handle the three switches better, but it's a little too big for just one delay pedal. the 1790 might be a little small for three stomp switches, but would easily house all the knobs and switches for this project.
Is there a way to have it either be a mix pot or a level pot? Like depending on the builders desire? Or is that a part of the PCB that's either one or the other.
I want this board when you're done Taylor. Also, I'd love to know if you're going to do that tap tempo trem board too.
Jacob
Yes, the mix pot is just an option, you can do the regular level pot if you'd rather.
It's possible to do the loop in a couple of different ways, but the main one is where each repeat gets more effected by whatever's in the loop (the fx loop is in the feedback loop). I can't think offhand of what would be gained by putting an effects loop before the repeats, but if you want to effect the repeats only once - putting reverb on them for example - that should be doable. The trick here is making it easy to build for people who don't want every option - the more stuff you add the more jumpers and confusion come into play when just building it stock. I'll try to find the right balance.
I do plan to do the tap trem, but haven't begun on it yet. There seems to be a flurry of new work done on that tap chip, so I'm kind of waiting for that to get stable.
Cool, that will be an impressive board.
If you're going to add a mod kill switch you might be interested in this.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=42000&g2_serialNumber=1)
That's how I've implemented it in mine. This makes the LED flash when the modulation is on and just light up when it's off as well as acting as the effect on/off indicator, that way you don't need a separate modulation LED. It's best to use a super bright or ultra bright style LED that way you can use a big current limiting resistor like 50k or so, that way you don't run the risk of it ticking.
Ooh, that's very clever Slacker. I was planning to just short that 1uf cap, but that's a cool trick, I'll have to add it.
And I'll just take this chance to give props for my favorite of all the projects DIYSB'ers have come up with - the Echo Base is such a fun, great-sounding circuit, and a slick design to boot. And I find something strangely pleasing, aesthetically, about the schematic... :D
Quote from: Taylor on January 19, 2010, 04:46:21 PM
And I find something strangely pleasing, aesthetically, about the schematic... :D
Cheers, took me almost as long to draw the schematic as it did to design the thing.
You might want to check my version of the thing:
http://www.diystompboxes.com/smfforum/index.php?topic=78403.0
Quote from: Morocotopo on January 19, 2010, 05:44:12 PM
You might want to check my version of the thing:
http://www.diystompboxes.com/smfforum/index.php?topic=78403.0
Will do.
After digging, I realized that the Echo Base's LFO won't work right with the PTAP, so I may have to do a different LFO...
Also, I think I'll have to do the dual PTAP, so you can either do a single PT2399, or 2, but if you want tap tempo, you'll have to have 2 PT2399's. Can't think of a clean way to allow using either the single or dual PTAP.
Quote from: Taylor on January 19, 2010, 03:31:39 PM
tap tempo for the delay using the PTAP
I thought the PTAP wouldn't work (accurately) with the echo base without disconnecting the modulation?
Yep, see reply #7... someone said the Magnus Modulus (which is just the Tremulus Lune LFO) works with the PTAP, so I may go that direction.
It's not the LFO that PTAP doesn't work properly with, it's the fact that it uses a transistor to do the actual modulating. You can keep the LFO, but do the actual modulation using the method from the Magnus Modulus, which uses a resistor with a cap to add the modulation signal if I remember correctly.
the Ping Pong delay (I think from BYOC ) is a dual PT2399 that offers a longer delay amount. I would like to see this unit contain w Pt2399's. The Echo Base, Rebote and PT-80 all use one PT2399. I'm going to be building the latter two both with the ptap function, so one with more delay would be fun to have, and I would of course be adding the tap tempo function. That's just what I think though.
Jacob
You might want to have a look at this thread as well http://www.diystompboxes.com/smfforum/index.php?topic=78047.msg642998#msg642998 (http://www.diystompboxes.com/smfforum/index.php?topic=78047.msg642998#msg642998) it's got an improved version of the buffers that make the pedal a lot quieter.
Add those plus the other mods I posted and that's what mine's like at the minute, it's got a slightly reworked LFO as well but that's not really worth bothering with.
Quote from: jkokura on January 19, 2010, 06:40:48 PM
the Ping Pong delay (I think from BYOC ) is a dual PT2399 that offers a longer delay amount. I would like to see this unit contain w Pt2399's. The Echo Base, Rebote and PT-80 all use one PT2399. I'm going to be building the latter two both with the ptap function, so one with more delay would be fun to have, and I would of course be adding the tap tempo function. That's just what I think though.
Jacob
Jacob, as mentioned in the first post this will have a second PT2399 for double time.
Wait... the PTAP works with the EchoBase now?
ARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRUUUUUUUUUUUUUUGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
Did anyone ever try adding a compander to the echobase?
Quote from: Taylor on January 19, 2010, 07:04:16 PMJacob, as mentioned in the first post this will have a second PT2399 for double time.
Sorry, I thought that this was an idea, not a confirmed plan.
Jacob
Quote from: jkokura on January 19, 2010, 09:55:17 PM
Sorry, I thought that this was an idea, not a confirmed plan.
Jacob
Yep, everything in that list should end up in the PCB, unless for some reason it just can't be done. I've budgeted space for all that stuff, and the PCB is mostly filled. Just working out the finer details of the PTAP. Besides integrating the LFO and the PTAP, we actually need a customized PTAP for this, since having 2 PT2399s means each one needs to be programmed for half the tapped time. I'm trying to verify with the maker of the PTAP that we can get this to happen.
Quote from: slacker on January 19, 2010, 06:34:43 PM
It's not the LFO that PTAP doesn't work properly with, it's the fact that it uses a transistor to do the actual modulating. You can keep the LFO, but do the actual modulation using the method from the Magnus Modulus, which uses a resistor with a cap to add the modulation signal if I remember correctly.
So is it as simple as this?
(http://img710.imageshack.us/img710/1205/modulusbaselfo.jpg)
If that's all that's necessary, and I hope this doesn't come across the wrong way, but why did you decide to do the modulation with the transistor?
Very nice features, looks great to me! what about calculating dotted 8Th's' etc ?
Quote from: Taylor on January 20, 2010, 01:24:59 AM
So is it as simple as this?
Yeah, that should do it. You'll probably need to tweak the value of the 240K resistor between the LFO and the depth pot, or remove it all together, because that's dropping the voltage down to what the transistor wants. I haven't actually tried this method so I don't know how the performance compares with my method, but the clips of the Magnus Modulus sound good.
Quote
If that's all that's necessary, and I hope this doesn't come across the wrong way, but why did you decide to do the modulation with the transistor?
Perfectly reasonable question :) the short answer is I didn't know you could do it like that. I've no idea how ForcedFIre came up with that idea, but it's a very neat solution.
The long and boring answer is that no one really knows how the delay is set in the PT2399, except that changing the resistance between pin 6 and ground controls the time, that's all the data sheet tells you. There's plenty of speculation about how it works, but as far as I know no one's ever figured it out.
So everyone who's ever attempted to voltage control the chip, except Mr ForcedFire, has used some sort of voltage controlled resistance to do it. A couple of people here added LFOs to Rebotes using vactrols to control the delay time, that's what started me off on the Echo Base. I decided not to use vactrols because depending on where you come from they can be difficult to get hold of and can be expensive, and if you roll your own the results would be too variable and you'd need to add trimmers or do a lot of tweaking to get consistent performance.
I researched it a bit and found a couple of synth DIY guy's had done VC PT2399 designs, one used a JFET, but I decided against FETs mostly because I didn't have any and partly for the same reasons as for vactrols. The other design used a more complicated method using a transistor so I went down that route but using something simpler.
Quote from: SPAZ on January 20, 2010, 08:02:29 AM
Very nice features, looks great to me! what about calculating dotted 8Th's' etc ?
Yep, the PTAP does quarter/eighth/dotted eighth/triplet eighth. It
may even be possible to set the 2 chips to different divisions for cool polyrhythmic sounds, but it's not a definite yet.
http://thoughtprocessinc.com/ptap2
That does it then, I've now thrown my name in the hat twice now :icon_lol:
I'll take a PCB when they're done - and thanks for putting this together Taylor. 8)
PCB, Rick? :o ???
The other Perfborgs are going to excommunicate you...
Quote from: Taylor on January 20, 2010, 03:55:06 PM
PCB, Rick? :o ???
The other Perfborgs are going to excommunicate you...
There can be only one!
Quote from: Taylor on January 19, 2010, 03:31:39 PM
tap tempo for the delay using the PTAP
double time mod using a second PT2399
effects loop
modulation kill switch
feedback filter, to get filtered analogish repeats
oscillate momentary stomp switch
board mounted pots
mix pot
Too tasty to turn down I'm afraid!
I would definitely be interested in getting one of these PCBs.
I would like to get one as well, 5 for future projects if the price will be low :)
I'd be down for a couple boards as well. This looks like a fun project.
I don't care what features get chosen, but put me down for two.
definitely interested in this project taylor!
perhaps you could add a preamp to the output akin to the echoplex-style FET boosters?
I'm not familiar with that, except that I remember some pedal company selling an Echoplex-derived standalone preamp.
What does this preamp do that's special?
its just a tonal thing. i've been thinking of including it in delay/loop pedals on the wet signal only for a more "tapey" effect.
here's some info. http://www.madbeanpedals.com/docs/FatPants/Fatpants_ver1.pdf
but of course, i just realized this could be inserted by me if theres a wet signal effects loop.
Adding boost before the PT2399 isn't a great idea, the chips runs off 5 volts so there's not much headroom to start with, if you start adding boost, you're not going to get anything "tapey" you'll just get horrid opamp clipping. It's possibly something to experiment with if Taylor adds an effects loop, but I don't think it's worth building it in.
Quote from: slacker on January 21, 2010, 12:23:41 PM
Adding boost before the PT2399 isn't a great idea, the chips runs off 5 volts so there's not much headroom to start with, if you start adding boost, you're not going to get anything "tapey" you'll just get horrid opamp clipping. It's possibly something to experiment with if Taylor adds an effects loop, but I don't think it's worth building it in.
I think aziltz was thinking about putting it on the output ??? To filter the sound maybe?
Quote from: mth5044 on January 21, 2010, 12:34:52 PM
I think aziltz was thinking about putting it on the output ??? To filter the sound maybe?
yes, output.
Yeah, I don't think I'll have room to implement that.
no worries, i'm still wanting one. will there be an effects loop send/return?
Have you ever built the Echo Base with double delay time? I did and I had a lot of problems with the feedback being too silent (after the second repeat you couldn't hear any delayed signal anymore). This problem has been addressed in the Echo Base topic, but Slacker hasn't gotten back to me on it.
Actually, no I haven't, but I have read your posts about it. I know it's doable because I think there's a BYOC project that does it. It's something that I have to experiment with to get it working right.
Dammit, I'm sitting building an Echo Base, but this is starting to sound too attractive with all these mods nicely integrated. I'm in.
Lots of fun to be had with 2 separate delays... :)
this sounds like an awesome project! i'm definitely down for a couple boards if the price is right. i've been wanting to build a delay for a while now anyway.
oh, hi everyone. i'm new here, but i've been building for a little while now. i'm not advanced by any means, but i really enjoy being able to make pedals that are unavailable and/or better and custom versions of current pedals. hopefully, i'll be able to design my own stuff someday too. :icon_smile:
Welcome cap10random. I'm not actually advanced either, but I'll get there one day. You'll find that the people on this forum are extremely generous with their knowledge as long as you're willing to put some legwork in.
It's too bad that Princeton didn't make an echo chip with enough delay time bits to be useful for tap tempo :icon_frown:
4 bits is their best selection range but that's not near enough to do anything with. They had a serial port control on one of their chips too I believe where you could manage the entire chip in serial instead of parallel, if only they had an 8-bit serial delay input... SIGH
Quote from: Taylor on January 21, 2010, 12:55:24 AM
I'm not familiar with that, except that I remember some pedal company selling an Echoplex-derived standalone preamp.
What does this preamp do that's special?
I think it was just a certain "tone" that they felt was popular enough to warrant putting it in a standalone pedal. Maybe it has particular frequency responses or distortion characteristics that sound good? I don't think it has any merit in regard to delays specifically though considering their choice putting it in a standalone.
I'd be interested in getting a board or two as well.
Quote from: JKowalski on January 22, 2010, 12:24:58 AM
I think it was just a certain "tone" that they felt was popular enough to warrant putting it in a standalone pedal. Maybe it has particular frequency responses or distortion characteristics that sound good? I don't think it has any merit in regard to delays specifically though considering their choice putting it in a standalone.
i'll be making on anyway. we'll see how it sounds. the idea was to get the delays sounding a little more different than the dry, and you could tell your buddies it "sounds" like an EP3
how's this going btw? Is there a timeline in mind?
No timeline really. I'm finishing up the tap tempo tremolo board first, then I have a lot of stuff with my own designs that I'm trying to finish quickly.
I would estimate that the design will be done in a week or 2, and then when it's done it'll be about 4 weeks before boards are available for sale.
Taylor, as a matter of course, please count me in for two of any project your warped genius conjures up. Including this. And the tap trem. And the hover boots.
Taylor, would it be too much to ask you to share some thoughts or your process on getting these PCB projects made?
I for one would be interested in hearing about how to do this, either now or later.
thanks,
A
Quote from: markeebee on January 28, 2010, 02:54:37 PM
Taylor, as a matter of course, please count me in for two of any project your warped genius conjures up. Including this. And the tap trem. And the hover boots.
I'm starting to wonder if Markeebee is a sockpuppet acount I created during my somnambulism to puff up my own ego... Seriously, though, I can't take much credit for any genius here, I'm basically just assembling parts of schematics other people came up with. But I do appreciate the kind words.
Incidentally, DIY personal flight actually IS an interest of mine. I do plan to build a backpack helicopter one day, and I will hook you guys up with kits if you want. :D
Quote from: aziltz on January 28, 2010, 03:57:42 PM
Taylor, would it be too much to ask you to share some thoughts or your process on getting these PCB projects made?
I for one would be interested in hearing about how to do this, either now or later.
I'm not sure I know what you mean. Are you interested in getting PCBs made of your own circuits, or...?
Basically, I do the design in a CAD program, get prototype boards made, build up the proto, and if it works right I get the bigger run made. Let me know if there's a specific part of that process you'd like to know more about.
id be in for 2 boards
I'm in for a couple!
New to this forum, but I'm the process of doing a BYOC with the dual PTAP2. I'd love to see all this in one board with those other features you listed. Sign me up for a few!
I'd be in for a board or two!
Just outta curiosity, what's the timeframe on this? I'm mostly wondering if I should hold off a few weeks on a parts order to get parts for this on as well, or if it's gonna be a month or more and I'll just save it for a different order.
Quote from: Taylor on January 28, 2010, 02:33:33 PM
No timeline really. I'm finishing up the tap tempo tremolo board first, then I have a lot of stuff with my own designs that I'm trying to finish quickly.
I would estimate that the design will be done in a week or 2, and then when it's done it'll be about 4 weeks before boards are available for sale.
From two weeks ago. Taylor's pretty good about communicating where he is in the process as far as I've seen. I don't think there's a hurry on this one as there's another project to finish for him in front of this one.
Jacob
The PCB design is not quite done. I will probably finish it in the next couple of days. Then it'll be a week and a half until I get the prototypes. Then another 2 weeks for the big batch to be made. So we're probably about a month from the point I can start actually shipping boards.
It's almost done now, need to sort out the finer details of the cascaded delay chips.
But I think I'll have to lose the feedback filter. Just can't find room for it. Or, does anybody know of a low parts count bandpass filter?
I haven't seen this done, but what if you cascaded an RC lowpass and RC highpass, with the highpass cutoff set lower than the lowpass's? Is there any way to vary frequency of something like this without a dual-gang pot?
Two separate delay lines sound cool. I remember some algorithms in my old Lexicon Vortex, you can do thing like series or parallel arrangements with some cross feedback lines... You can extend the delay time limit or add some new combinations. It can be done with simple switching. Congratulations and I want one or two of them.
Oh, and a companding is a real good addition, the sound is very clode to analog type echo, well... I like it.
Unfortunately, there isn't any room left to do companding, unless people were willing to build this is something bigger than a 1590BB.
the 1790NS isnt much bigger than a 1590BB, especially if you want more than 5 knobs, 2 jacks or 2 footswitches.
I'll be building it into a 1590DD for one with 3 switchs, and maybe the second into a 1790NS for a version using 2 switches.
Jacob
Yikes, this is a tough PCB. It's 99% there, but that last 1% is recalcitrant. I've been trying to decide how to handle the 2 delay chips. At the outset, I only thought I'd use them in series for double time. But it really does seem a shame to have 2 delay chips and not allow for crazy parallel delays.
Plus, imagine how awesome it would be to have 2 delays in parallel using the PTAP: since it allows you to do different divisions of the tapped tempo, you could set the delays to be perfectly in sync in a 4-to-3 time relationship, without having to tweak the delays really carefully. Just tap in your time and out comes a perfectly synced polyrhythmic delay!
So the only problem is doing the PCB in such a way that you can do those wacky things, but figuring out how to build it isn't a chore. I really like the majority of the build to be obvious just by looking at the board, without having to dig through a PDF, and I've mostly achieved that. But this parallel/series switching is going to be really hard to pull off cleanly.
Quote from: alex frias on February 12, 2010, 09:06:22 AM
Two separate delay lines sound cool. I remember some algorithms in my old Lexicon Vortex, you can do thing like series or parallel arrangements with some cross feedback lines...
Now that thing is one of my favorite effects units ever. I think it was the "Bleen" preset, which was like a multi-tap delay with a ring modulator in the feedback loop... that, plus an Ebow was "my sound" for awhile. I need to code up a workalike in the FV-1 chip now that I don't have my Vortex anymore.
Taylor, this is going to be terrific! Keep it up! :icon_cool:
Hello Taylor,
I want 1 board to when your done, great job.
And with 2 parrallel delays one set to 1/8* and the other on 1/4 you get an instand The Edge sound ;)
Ronald
I'm considering adding some optocouplers to the circuit to provide a dual feedback control from one knob. My question to you guys:
Are optocouplers hard to get in Europe? I figure that with ROHS they're supposed to be banned, but it looks like Banzai has them.
Would it make the circuit harder to build for ROHS-affected countries if there were a couple of optocouplers?
^^^
Real men roll their own.......
Quote from: frequencycentral on February 15, 2010, 08:11:53 PM
^^^
Real men roll their own.......
True, but what about Europeans?
:D But anyway, it's not optocouplers only that are banned by ROHS, but CDS cells, which you need to roll your own. So I just want to confirm that it's not hard for European DIYers to get their hands on opto-things.
I use these little guys, still readily available: http://cgi.ebay.co.uk/LDR-Light-Dependent-Resistor-Lot-of-5_W0QQitemZ120343782559QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Supplies_ET?hash=item1c050c649f
Or if you're thinking a dedicated part will be more reliably accurate, this European would be OK with Banzai. :icon_biggrin:
In this case I don't think accuracy matters too much, since it would be controlling feedback, so I don't think matching is that critical.
Here in europe we have lot's off places to get optocouplers.
Ronald
The NEtherlands
Maybe it's a ploy to get us to buy 20yrs worth of LDR's each. Let's build with them while we've got 'em.
Quote from: Taylor on February 11, 2010, 01:30:55 PM
The PCB design is not quite done. I will probably finish it in the next couple of days. Then it'll be a week and a half until I get the prototypes. Then another 2 weeks for the big batch to be made. So we're probably about a month from the point I can start actually shipping boards.
Awesome, thanks. I'm definitely in for two of the boards.. I can't wait for this thing. I'm just finishing up a rebote which should keep me tided over, but I'm looking forward to one or two of these to play around with...
Really hoping it ends up with the parallel delays feature or even greater, capability of parallel and series.
Also I hope you don't get hung up fitting it for a little box and sacrifice some features... good luck!!!
Yep, it's looking like you'll have the ability to do parallel and series, but it will require a 4PDT toggle switch, which is $6. You're right that I am kind of hitting up against a wall since I designed this for a BB from the outset. I think it will still fit in a BB, but to get the full features you'll want a 1790 or bigger.
I'm still going back and forth between a dual pot and an optocoupler solution - talking to Small Bear about them carrying the PC mount dual pot.
That's great news. $6 extra for a toggle is a small price to pay for this feature. yeah, go all the way and make your efforts count.
Quote from: jkokura on January 19, 2010, 03:41:37 PM
Is there a way to have it either be a mix pot or a level pot? Like depending on the builders desire? Or is that a part of the PCB that's either one or the other.
Is there a reason you'd prefer a level pot to a mix pot? Originally I wanted as much flexibility as possible, but as the board gets more complex, this is harder to maintain. I'm thinking I will go with one or the other. The Mix pot seems more versatile to me. What do you think?
Also, as this project becomes larger, I wonder if there would be interest in a different board that was just a stock Echo Base? Smaller, simpler, less options, but easier and cheaper to build, and still with the luxuries of silk screen, solder mask, and plated pads. This simple one could even fit in a 1590B. Does that appeal to anyone?
I would take one straight Echo Base pcb, and I'm in for 2 of the bigger ones.
Jacob
I'm all for the mix pot.
As for a simpler board, I'd get a couple, but I'm REALLY excited about getting some of the Super tricked out boards! :icon_razz:. I don't care how big it is, I'll put it in a rack if I have to.
Ry
Quote from: Taylor on February 17, 2010, 07:59:00 PM
Yep, it's looking like you'll have the ability to do parallel and series, but it will require a 4PDT toggle switch,
Why? You can do parallel/series switching with a DPDT, or are you using the extra poles to switch other things?
Quote from: Taylor on February 18, 2010, 03:58:34 AM
Quote from: jkokura on January 19, 2010, 03:41:37 PM
Is there a way to have it either be a mix pot or a level pot? Like depending on the builders desire? Or is that a part of the PCB that's either one or the other.
Is there a reason you'd prefer a level pot to a mix pot? Originally I wanted as much flexibility as possible, but as the board gets more complex, this is harder to maintain. I'm thinking I will go with one or the other. The Mix pot seems more versatile to me. What do you think?
You can give the builder the option of having delay level or a mix control fairly easily, it just needs a couple of extra solder pads adding to the original schematic, I'll knock up a drawing. If you go with a mix control though there's no way you can use the original switching, you'd either have to true bypass it or use buffered bypass, but either way you'd lose the tails feature.
Personally I don't see the appeal of a mix control, but if it's is something a lot of people wanted I could have a go at redesigning the switching to allow for it and keep the tails feature.
Quote from: slacker on February 18, 2010, 12:49:23 PM
Why? You can do parallel/series switching with a DPDT, or are you using the extra poles to switch other things?
Well, I'd love to see how you'd do it. Here's what I worked out.
We need to switch these things:
In parallel mode, the output from the input 4066 switch needs to go to the inputs of both PT2399s. In series mode, the input to the second delay chip needs to be cut out.
In parallel, the output from the first delay needs to go to its own feedback knob (half of a dual gang pot) which then goes to the input of the same delay. In series mode the output of the first delay needs to be switched to go into the second delay's input.
In parallel mode, the output from the second delay chip needs to be fed into the input of the same chip. In series, the out from the second chip needs to be fed back to the in of the first chip.
The PTAP has a series/parallel mode switch that needs to be switched simultaneously.
I'm definitely no guru, so if anyone can think of a more efficient way to switch all this, it would be great.
Quote from: slacker on February 18, 2010, 12:57:26 PM
You can give the builder the option of having delay level or a mix control fairly easily, it just needs a couple of extra solder pads adding to the original schematic, I'll knock up a drawing. If you go with a mix control though there's no way you can use the original switching, you'd either have to true bypass it or use buffered bypass, but either way you'd lose the tails feature.
Personally I don't see the appeal of a mix control, but if it's is something a lot of people wanted I could have a go at redesigning the switching to allow for it and keep the tails feature.
I do want to keep the tails and switching. I have a schem that somebody did that incorporates a mix knob at the opamps, didn't change the switching, is there some reason that doesn't work? Can't find the schematic right now, but it's buried in the Echo Base thread.
I would just like the ability to cut the clean signal to get vibrato sounds. Even a switch to kill the clean would be useful to me.
Quote from: Taylor on February 18, 2010, 02:19:48 PM
Quote from: slacker on February 18, 2010, 12:49:23 PM
Why? You can do parallel/series switching with a DPDT, or are you using the extra poles to switch other things?
Well, I'd love to see how you'd do it. Here's what I worked out.
My thought was just to switch the inputs and outputs of the delays between series and parallel, which you can do with a DPDT, I hadn't thought about the extra stuff you're switching. I was thinking of having separate feedback pots and connecting them both back to the input of the first delay. That way in series you can tap the feedback from either the first delay or the second or a mixture of both.
QuoteI do want to keep the tails and switching. I have a schem that somebody did that incorporates a mix knob at the opamps, didn't change the switching, is there some reason that doesn't work?
I can't remember what the person who posted the mix pot mod did, so I might be wrong and it might work fine, I'll have a look at it.
My concern is that in the original design the dry signal goes through the pedal unaffected by the the bypass switching, this only affects the delayed signal. If you add a mix pot then potentially you're changing the level of the dry signal which means the bypassed volume will change depending on where the mix pot is set, in a worst case if you had 100% wet and then bypassed the effect you'd get silence.
Here's the mix pot mod from the Echo Base thread http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg556933#msg556933 (http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg556933#msg556933) looks like it was meant to be used with true bypass, it definitely won't work properly with the original switching.
I think I've come up with a way to do a mix pot that will allow anything from 100% dry to 100% wet and let you keep the tails, it just means using a DPDT stomp for the bypass which doesn't seem like a problem to me. I'll have to breadboard it to see if it works, if it does I'll post a schematic.
Quote from: slacker on February 18, 2010, 03:27:22 PM
Here's the mix pot mod from the Echo Base thread http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg556933#msg556933 (http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg556933#msg556933) looks like it was meant to be used with true bypass, it definitely won't work properly with the original switching.
I think I've come up with a way to do a mix pot that will allow anything from 100% dry to 100% wet and let you keep the tails, it just means using a DPDT stomp for the bypass which doesn't seem like a problem to me. I'll have to breadboard it to see if it works, if it does I'll post a schematic.
Cool! I assume most people would be using a DPDT at least anyway, since SPST latching switches are less commonly available than DPDT stomps.
Quote from: slacker on February 18, 2010, 02:56:18 PM
My thought was just to switch the inputs and outputs of the delays between series and parallel, which you can do with a DPDT, I hadn't thought about the extra stuff you're switching. I was thinking of having separate feedback pots and connecting them both back to the input of the first delay. That way in series you can tap the feedback from either the first delay or the second or a mixture of both.
I did a little simulation on my computer, and doing it this way makes the echos stack up arhythmically until they become really diffused and sound like a reverb. The way I'm doing it is the only way I could come up with while allowing the delays to act right. The 4PDT is going to be board-mounted, so you won't have to deal with wiring such a monster.
Here's a quick schematic of the mix pot idea, I simulated it and it seems to work ok, I'll see if I can try it out at the weekend. The switch would be part of the bypass stomp. It might be possible to use the spare CD4066 switch instead, that would be a bit more complicated and probably not worth the effort. If it works it would be easy to build either this or the level pot using the same PCB layout.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=42289&g2_serialNumber=1)
When the effect is on the switch would be closed shorting the 1M resistor and the mix pot would then give you anything from 100% wet to 100% dry. In bypass the switch would be open and the 1M resistor then basically isolates the dry signal from the pot so you get the straight dry signal with the tails mixed in at what ever level they are set at by the pot.
That's the theory anyway :)
I think you are onto something with the standard board and the turbo board Taylor. I may not be so interested in the standard E.B. having built it already, but there's new builders arriving all the time who I believe would appreciate it. Perhaps a new newb-friendly thread when you are ready with it. It's a complicated build to perf, so it requires the ability to etch and not everybody has that option to begin with.
That way you could push this turbo board to the limit. Compact is good, but don't restrict the board size at the expense of useful features.
QuoteI'll put it in a rack if I have to.
+1
Looking forward to another cool pedal, thanks Taylor.
@ Ian, great you can find time to help with this.
Hey Taylor, the BYOC Ping Pong does the series/parallel switch via toggle in mono. Perhaps checking out that schem might help? They keep em posted in their build instructions.
-Austin
Quote from: aziltz on February 18, 2010, 11:19:59 PM
Hey Taylor, the BYOC Ping Pong does the series/parallel switch via toggle in mono. Perhaps checking out that schem might help? They keep em posted in their build instructions.
-Austin
Yep, I've looked at their switching setup. Don't want to say negative things because I guess in a weird way I'm now a "competitor" of theirs (I don't see it that way, but somebody might), but the way they do it isn't really satisfactory for my purposes. The reason is that it doesn't allow any feedback for one of the delay lines in parallel mode. So it wouldn't allow you to do the cool 3-against-4 rhythmic repeats or the "The Edge" thing with 2 repeating delays at different multiples of each other.
Their setup gives you one repeating delay and the other delay just repeats once and that's it. Plus, they still do it with a 3PDT, and they don't have to switch the PTAP, so not only is their switch less capable but it's also less efficient with poles. :icon_biggrin:
So their thing is perfectly respectable and it does its own thing which is cool, but it's too limited for my tastes. If you're going to go to the trouble of doing a dual delay, you may as well go the whole nine with it, right?
oh ic. I haven't built it, only looked at it briefly, but I agree we should go the distance!
I got chance to try out the mixer idea I posted earlier and it seems to do what we want. Some of the values will probably need tweaking to get the best balance of the wet and dry signals and maintain a constant volume between bypassed and effected but it basically works. Even hooked up with a bunch of crocodile clips there's no popping or other nasties when switching and tails work like on the original.
I have to admit the 100% wet setting is pretty cool for vibrato sounds and the chorus sounds seem a bit easier to dial in.
Quote from: slacker on February 20, 2010, 12:35:53 PM
I got chance to try out the mixer idea I posted earlier and it seems to do what we want. Some of the values will probably need tweaking to get the best balance of the wet and dry signals and maintain a constant volume between bypassed and effected but it basically works. Even hooked up with a bunch of crocodile clips there's no popping or other nasties when switching and tails work like on the original.
I have to admit the 100% wet setting is pretty cool for vibrato sounds and the chorus sounds seem a bit easier to dial in.
Very cool, I will have to incorporate into the PCB.
I have set aside the "gigantor" PCB for a second, because it was getting a little taxing on my brain. PCB layouts are much like complex puzzles and you know how it goes when you work on the same puzzle for weeks - you really need to put it down and come back to have a clear head about it.
In the meantime I completed a simpler Echo Base board. It has the updated input and output sections for cleaner operation, less hiss. It's got just a couple of little mods that don't take up room (the status LED flashes with the LFO, there's an option for an LFO kill switch), but other than that it's stock. Best of all it, it will fit, with stomp switch, jacks, etc. in a 1590B box, oriented landscape style ala ZVex.
On the Gigantor front, I heard back from Steve at Small Bear regarding the dual PC mount pot. Good news: he's going to carry it. Bad news: he said "look for it in late Spring, early Summer". :icon_sad: I don't really want to design the board for a part that no one can get for 5 months. So I guess I'll go with optocouplers. :icon_confused:
What's special about the dual gang pot you want to use? Is it a vertical mount with the long legs? Otherwise we could just accept that one pot needs to be wired and use a more common dual pot with lugs. Wouldn't a vertical mounting dual sit higher than the other pots anyway. Can't see the problem, could you sketch the way you want to mount it?
Quote from: Skruffyhound on February 20, 2010, 04:34:51 PM
What's special about the dual gang pot you want to use? Is it a vertical mount with the long legs? Otherwise we could just accept that one pot needs to be wired and use a more common dual pot with lugs. Wouldn't a vertical mounting dual sit higher than the other pots anyway. Can't see the problem, could you sketch the way you want to mount it?
+1
Design to wire in a standard lug dual pot and focus on the more ambitious "Gigantor" model... something worth getting excited about.
Small boxes are for small men. :icon_twisted:
Hmm, ok. I just hate offboard wiring - it's so much faster and cleaner to do board-mounted pots, but that's just me.
So you guys would prefer to wire a solder lug dual pot than use optocouplers?
Generally I'm in favour of PCB mount everything, but since I can't see how this vertical mount dual pot will align with the other pots anyway then I could make an exception and wire 6 lugs. So yes I'd prefer the pot to opto's
Quote from: Skruffyhound on February 20, 2010, 07:02:20 PM
Generally I'm in favour of PCB mount everything, but since I can't see how this vertical mount dual pot will align with the other pots anyway then I could make an exception and wire 6 lugs. So yes I'd prefer the pot to opto's
Check out the drawing, it's the last one on this page:
http://www.taiwanalpha.com/english/p_e_50.htm
Then compare to the penultimate pot on this page:
http://www.taiwanalpha.com/english/p_e_49.htm
The pot body is slightly larger on the dual pot, but the distance between the top of the body to the pins is the same. It
should line up right, but there could be some little thing that I'm not envisioning properly. The pots in this case will not sit against the board, but sort of hang off the side (disregard the negative mechanical connotations of the word "hang" - it should be quite sturdy).
Just out curiosity, what about optos do you object to? I realize they are not really accurate for things that need to be really matched, but in this case it's just for the 2 feedback pots, which in my experience it's not really a big deal if the feedback of the 2 sides isn't perfectly matched - since there's no option for stereo operation here, I doubt anyone will use the 2 sides set to the same speed, so you won't notice if they have slightly different feedback amounts.
I'm not in the habit of building with mounted pots anyway 'cause I like the freedom of placement (in a larger enclosure) , so soldering up 6 lugs is nothing to get hung up on for me.
My personal concern is I won't be able to buy a load of opto's to sort through if you go that route.
Mainly I hope you don't lose patience and do the junior version. Looking forward to seeing how this ends up.
Quote from: bluesdevil on February 20, 2010, 08:37:13 PM
I'm not in the habit of building with mounted pots anyway 'cause I like the freedom of placement (in a larger enclosure) , so soldering up 6 lugs is nothing to get hung up on for me.
My personal concern is I won't be able to buy a load of opto's to sort through if you go that route.
Mainly I hope you don't lose patience and do the junior version. Looking forward to seeing how this ends up.
I'm doing both, don't worry. I think it's good because the plain old Echo Base is still a killer effect without all the bells and whistles, and the Gigantor is going to be a bigger build than a lot of newer DIYers want to mess with at first.
I guess I will just do the board for the dual pot. For the time being, people can build it with a solder lug pot, then when the board-mount pot becomes available, that will be an option.
I'm already envisioning the two pedals side by side...
The "AT-ST" and the "AT-AT"
All this talk of Echo Bases is making me want to watch the Empire Strikes Back.
With these PCB's we will come up with names for pedals that totally make us look like Geeks to everybody else.
Jacob
Hate to break it to you, Jacob, but I think the nature of this hobby already makes us look like geeks to everybody else. ;)
It's made up for by the way people think I'm an insane genius about electronics out in the real world. Then I come on here and feel like I barely know anything. This forum is good for a reality check.
Quote from: Taylor on February 20, 2010, 03:34:50 PM
In the meantime I completed a simpler Echo Base board. It has the updated input and output sections for cleaner operation, less hiss. It's got just a couple of little mods that don't take up room (the status LED flashes with the LFO, there's an option for an LFO kill switch), but other than that it's stock. Best of all it, it will fit, with stomp switch, jacks, etc. in a 1590B box, oriented landscape style ala ZVex.
Sweet, can't wait to see that :)
I'd just go with the dual pot for the feedback, that way people have the option of using 2 separate pots if they want to, which is probably something I'd experiment with.
Yeah OK, if they are out over the edge of the board then I think you are right, there seems to be the same 10.7 mm on both from pins to base of shaft.
I don't care that much either way, there is just always a certain amount of messing about with opto's and as can be seen from every thread about an effect that uses them, they are not consistent between builds. It may, as you say, be a non-issue here, a dual pot is just clean and one less variable when comparing notes or building a few units, and if I'm honest I have amassed quite a stock of them and rarely get to use one ::)
Just go with what makes the most sense for the largest number of people.
Hi Taylor,
I don't want to rush you but how does the work go on this PCB?
regards
RonaldB
Coming along. I sort of put it aside because I know I'm not going to have the dough to order the PCBs right away. Need to scrounge some dollars first... :-[
I'd be willing to chip in a few bucks to a collective fund to offset some costs for you. I'm pretty excited to try one of these out...
Anybody else?
I'm also the one up for it :icon_cool:
Yes, ask for pre-orders, and we will likely provide you the funds to make it happen. I'll pre-order.
as would i
That's ok, I think I've got it sorted out. I'll finish up the design soon and we can move this project forward. :)
I'd like to order a board and will happily pay now, no matter how long it takes :icon_cool:
I'm in for a board or two myself. I'm in need of a delay with some longer repeat times, and I love modulated delay.
Hey Taylor, I'm totally in for a coupla boards (as likely a couple of my friends will be too).
Love what you do, thanks a bunch; you're a total champion.
A couple people PM'ed me about this, so I figured an update was in order. The simpler, but updated Echo Base PCBs are available (here (http://www.diystompboxes.com/smfforum/index.php?topic=83525.msg694322#msg694322)) but I haven't been able to complete the Gigantor, and here's why:
I'm not really a circuit designer. My skills as an electrical engineer are woefully lacking. I'm pretty decent at layouts, but I don't really have the knowledge or time to breadboard a circuit and figure out all the tweaks necessary to make it work. This tap-tempo delay project started to get so far from any verified schematic that I realized I really need to build some prototypes before I bother getting PCBs made, and I just haven't had the time yet.
However, I have a good track record so far of actually completing all the PCB projects I've so far committed to, so it will happen. If anybody has some time to breadboard a prototype of a large circuit, let me know, and we can work together on this.
Hi Taylor,
I'm guessing this project is shelved for the time being? I'm really keen on building a full featured dual pt2399 delay with decc's ptap. The schematics I've seen for a dual implementation of the echo base with all the buffers/mods look to be very tough to layout. Have you made any progress? Do you have any layouts that you'd like tried out and verified?
Travis
Unfortunately yeah, just haven't had the time needed to do this. If I had a verified schematic I could do the layout, as I had it mostly completed back in February. What schematics have you seen of dual tap tempo Echo bases?
If anybody out there is up to work out some of the details of the circuit design and put together a final schem, please contact me and we can work out the details ($)
the BYOC Dig. Delay is a Dual PT2399 and there is a PTAP design to mate with it. I guess you could consider those pieces as being verified separately.
Ah, right, but as I recall I thought the way they implemented the 2 chips was really limited. I think if you use them in "parallel" they still sum before the feedback, which means you can't have separate feedback lines for each, which in turn makes the 3-on-4 rhythmic delays we had planned with this project impossible. I'll try to dig back into this project when I get a little time, because it's a fun project.
Quote from: Taylor on July 27, 2010, 02:23:43 AM
Unfortunately yeah, just haven't had the time needed to do this. If I had a verified schematic I could do the layout, as I had it mostly completed back in February. What schematics have you seen of dual tap tempo Echo bases?
On Aron's site, there's a very detailed schematic produced by Christopher Sewell. I'm not sure if this implements dual pt2399 in the way you envisioned, and if it can incorporate all the features you were considering:
http://www.aronnelson.com/DIYFiles/up/Echo_Base_-_Stereo_Dual_Echo_-_complete_schematic.pdf
Hm, interesting. I will check into it further. Would be cool to get this project going again.
What would the difference in sound be between a serial or parallel dual delay like that?
The way I imagine it, in parallel you split your dry signal to route through two seperate delays, which can either be summed or sent to two different outputs. In serial, you essentially stack the delays, so that the signal get's delayed once, then the already delayed signal get's delayed again. Do I have it right?
Jacob
There are lots of different ways to do it with different results. What I want is for series mode to act like a single delay pedal, but with double the amount of time that a single PT chip can do. This means sending it through the delay chip, then sending that delayed signal through the second chip, but not using the output of the first chip directly.
Then, in parallel mode, they are totally separate chains until they mix at the end. This, combined with the cool ratio knob of the the PTAP, allows you to tap in a time, but have one delay repeat 3 times for every 4 repeats of the other - this makes for very interesting rhythmic possibilities. Or you can have one set to fast repeats and the other to repeat every fourth beat, the classic U2 Edge thing. Doing this requires separate feedback paths for the 2 delay chips.
The way BYOC has it on theirs, in parallel mode there's no feedback on one of the delay lines, and they sum together and get repeated through just one delay. If you listen to their clips you can hear what I'm talking about, but it's pretty limited. Totally reasonable to keep it simple since it's their only PT delay, but for my project I want to do something crazy and deluxe.
Awesome. I like the sound of that.
I can see this with three footswitches - Modulation, Tap and On/Off. Toggle or stomp for for series/parallel. Two full sets of control for the delays, one of which is completely bypassed in serial mode? Would we be able to get dotted eigths and other functions out of it or just straight time?
Jacob
The PTAP has these divisions possible: quarter/eighth/dotted eighth/triplet eighth.
You could also set up any crazy time relationship manually, of course. If you're a fan of Conlon Nancarrow you might want to set the time ratio to 60:61. :P Seriously, though, setting the 2 delays to almost the same time, then letting them slowly break out of lockstep with each other is the kind of thing I'd have fun with. They "reset" each time you play a new note.
Taylor, with Tone God's Taptation now available, your project has even more promise. My vision is for a triple delay pedal with tap tempo. It would be a dual echo base with tap tempo with serial/parallel as you described, and a basic slapback effect on the end as a third delay that can be stomped on anytime (maybe a rebote on the end).
Yeah, I need to read the Taptation datasheet. I'm not sure it has the ability to do dual delays with different times though. The PTAP2 is designed specifically for this. If the Taptation covers 2 different delays in time multiples of each other, plus an LFO, that would be quite nice indeed.
Stereo outs and the ability to run it 100% wet. Well, that's how I have mine set up now but I'm not too please with mine. Seems kinda noisy once you get the feedback above 9 oclock. I think a little darker repeats would be nicer as well as would doing away with the tails switch....or atleast putting it somewhere else.
I'd probably do a feedback tone control.
What do you mean by putting the tails switch somewhere else? You're building it, so you can put it wherever you like. Or am I misunderstanding you? If you don't want the switch, you can just put a jumper in the position you prefer.
Ok, as far as I can tell, the Taptation only handles one PT2399, so to use it for this project, we'd need 2 of them. Doesn't seem like a good solution to me. I think for this application, the PTAP2 is a better fit.
Glad this project is moving again, still following with interest.
Hm, I'm gonna tag on this thread. I have a PT2399 I'm dying to use, but I'd like something with tap tempo, I think. I like how the Echo Base sounds the best...:D
Hey Taylor, I'm messing around with the schematic myself, and I'm trying to understand some of the issues you've been trying to deal with.
For the parallel/series signal switching, you said that a 4PDT toggle sw would do the trick. Have you looked at using the SPDT switching of 4053 chips? I'm guessing you wouldn't want this as an onboard switching solution as it would take up premium board space.
I'm trying to understand why you need a dual gang feedback pot. What does this do for us instead of two single feedback pots, one per delay.
I think the optocoupler discussion was in regards to the difficulty finding a pc mount dual gang pot. I think Steve is carrying the dual gang pc mount pot now. How were you envisioning optocouplers as part of the solution? Are they no longer necessary?
Thanks,
Travis
Quote from: Beo on August 22, 2010, 03:56:15 PM
Hey Taylor, I'm messing around with the schematic myself, and I'm trying to understand some of the issues you've been trying to deal with.
For the parallel/series signal switching, you said that a 4PDT toggle sw would do the trick. Have you looked at using the SPDT switching of 4053 chips? I'm guessing you wouldn't want this as an onboard switching solution as it would take up premium board space.
Yes, when I was working on this I did think about IC switching, but I did the measuring and figured out that it would actually take up more space, when you count the extra passives needed, than an on-board 4PDT switch. However, now that my regular Echo Base PCB exists, I don't think size is as much of a constraint. I think people who want this pedal probably aren't too concerned with getting it into a 1590bb as I originally planned. So each would work about the same.
QuoteI'm trying to understand why you need a dual gang feedback pot. What does this do for us instead of two single feedback pots, one per delay.
Originally I planned to fit this into a BB as noted above. Separate pots for feedback just wouldn't have fit. I think there may have been other reasons, but it's been months since I was working on it, so to be honest I've forgotten some of the details. But having the pads for a dual pot does not preclude using separate pots.
QuoteI think the optocoupler discussion was in regards to the difficulty finding a pc mount dual gang pot. I think Steve is carrying the dual gang pc mount pot now. How were you envisioning optocouplers as part of the solution? Are they no longer necessary?
Right, optos would have been in lieu of the proper pot. But then I convinced Steve to get those pots made - the ones he has now are there specifically because of this project. So optos are not needed anymore.
I really want to make this project happen, but the unfortunate fact is that I just don't have time to do the breadboarding and play with the design. If there's anyone who is interested in helping with the design and breadboarding, please contact me to discuss $pecifics.
Quote from: Taylor on August 22, 2010, 04:13:18 PM
QuoteI'm trying to understand why you need a dual gang feedback pot. What does this do for us instead of two single feedback pots, one per delay.
Originally I planned to fit this into a BB as noted above. Separate pots for feedback just wouldn't have fit. I think there may have been other reasons, but it's been months since I was working on it, so to be honest I've forgotten some of the details. But having the pads for a dual pot does not preclude using separate pots.
...
I really want to make this project happen, but the unfortunate fact is that I just don't have time to do the breadboarding and play with the design. If there's anyone who is interested in helping with the design and breadboarding, please contact me to discuss $pecifics.
For the dual gang feedback pot to work, wouldn't you need it to be concentric so you can dial in two different feedback levels? Or does separate feedback levels offer little value?
Were you considering stereo output? I'm not particularly interested in this, but if we want a versatile pcb, others may want this feature.
I would like to help with the breadboarding. I have a few more components to acquire, including the PTAP2. I'll let you know when I'm ready to put something together.
Travis
Well, I guess my intention at the time was to allow for a single feedback knob to control both lines, again for size and to reign in the monstrosity. It didn't seem hugely useful to me to have different feedback amounts for the 2 sides. But again, by having pads for a dual-gang pot, it allows for either one control for both lines, or separate controls. Whereas if the board is designed for separate pots, you'd be forced to use separate pots. When possible, I try not to force people to build things one way.
Stereo outs might be a good idea. that wasn't part of the original plan, but I guess if the idea is to have the most souped-up delay possible, stereo is a good option. Just need to do it in a way that allows mono operation also, since most people still don't have stereo effects/amp rigs.
I plan on putting this into a large enclosure, but I still would like to minimize controls to those that are most useful. A single feedback knob would be nice.
In that regards, I'm guessing you were only going to have a single modulation circuit? If so, would this only go into delay1 or could it parallel into both PT2399s? Were you planning a waveform mod option?
Hmm, I think I only had one LFO at the time. But what the heck, may as well have separate LFOs for each channel, right? If we're going to go all-out, may as well go all-out. It only costs an opamp and some passives, really.
Waveforms, don't know. I haven't ever done the waveform mod on my Echo Bases. It seems fun but just never thought to do it yet.
What does everyone think? Would you want waveform knob(s)?
Not I said the Jacob.
Jacob
I'm working on my own version of the tap tempo chip, and still waiting for the digital pots to arrive, so the only thing i can do now is think. And i'm thinking, i wonder if it would be possible to use the digital pot to not just set the tempo for the delay, but also to do the modulation?
Quote from: Galego on August 23, 2010, 10:25:34 AM
I'm working on my own version of the tap tempo chip, and still waiting for the digital pots to arrive, so the only thing i can do now is think. And i'm thinking, i wonder if it would be possible to use the digital pot to not just set the tempo for the delay, but also to do the modulation?
Sure, why not
You'll just have worse resolution because of the digital potentiometer
Quote from: Taylor on July 27, 2010, 08:46:27 PM
Then, in parallel mode, they are totally separate chains until they mix at the end. This, combined with the cool ratio knob of the the PTAP, allows you to tap in a time, but have one delay repeat 3 times for every 4 repeats of the other - this makes for very interesting rhythmic possibilities. Or you can have one set to fast repeats and the other to repeat every fourth beat, the classic U2 Edge thing. Doing this requires separate feedback paths for the 2 delay chips.
So I don't see how to do this in the schematics I'm working on. If for parallel the buffered input connects to both PT2399s, how can you send the feedback of each delay into its own input and not sum into the other delay through the shared connection? Is there a way to isolate the split input such that each feedback only feeds its own delay without bleeding over to the other delay? Do the passives already provide this isolation as configured?
Also, how can a 4PDT do all the switching. We need two switches to configure each PT2399's input/output for parallel/series (the BYOC schematic shows this well), we need two switches to redirect the feedback outputs differently for parallel/series (each feedback to its own input for parallel, just the second delay feedback into the first delay input for series), and a fifth switch to indicate parallel/series to the PTAP.
Travis
Quote from: JKowalski on August 23, 2010, 04:28:30 PM
Quote from: Galego on August 23, 2010, 10:25:34 AM
I'm working on my own version of the tap tempo chip, and still waiting for the digital pots to arrive, so the only thing i can do now is think. And i'm thinking, i wonder if it would be possible to use the digital pot to not just set the tempo for the delay, but also to do the modulation?
Sure, why not
You'll just have worse resolution because of the digital potentiometer
Is there any way to smooth the transitions of the digital pot?
Quote from: Beo on August 23, 2010, 08:45:18 PM
Quote from: Taylor on July 27, 2010, 08:46:27 PM
Then, in parallel mode, they are totally separate chains until they mix at the end. This, combined with the cool ratio knob of the the PTAP, allows you to tap in a time, but have one delay repeat 3 times for every 4 repeats of the other - this makes for very interesting rhythmic possibilities. Or you can have one set to fast repeats and the other to repeat every fourth beat, the classic U2 Edge thing. Doing this requires separate feedback paths for the 2 delay chips.
So I don't see how to do this in the schematics I'm working on. If for parallel the buffered input connects to both PT2399s, how can you send the feedback of each delay into its own input and not sum into the other delay through the shared connection? Is there a way to isolate the split input such that each feedback only feeds its own delay without bleeding over to the other delay? Do the passives already provide this isolation as configured?
Also, how can a 4PDT do all the switching. We need two switches to configure each PT2399's input/output for parallel/series (the BYOC schematic shows this well), we need two switches to redirect the feedback outputs differently for parallel/series (each feedback to its own input for parallel, just the second delay feedback into the first delay input for series), and a fifth switch to indicate parallel/series to the PTAP.
Travis
Hey Travis, these are great questions and I wish I had time to delve into them right now. I have a bunch of notes and drawings from that time when I was working on it but I'm sure you'll understand that the details aren't fresh in my mind since it was probably 6 months ago or longer when I was working on this. I think at this point I would start over as the concept for the design has changed a lot. I'm just a little swamped right now and don't have time to work on the design. But again, if you or anybody has the time to work out the specifics of combining the various circuit fragments, we can work together to make the PCB project come to fruition.
Sure, I understand Taylor. If I get a design matured, I'll share it here so that others can help critique or improve it.
Well, i just finished the programming in my tap tempo IC (at least for now), don't know if anyone cares, but here goes anyway.
My version is quite more simple than what i have seen as i didn't really care about PWM (i did implement it at one point, but for now it's not working because i needed the input pin that used to be for the wave speed), also because i don't know what to do with it, my feeble attempts just resulted in a lot of noise from the PWM pulses.
I think the main feature i didn't see other people using is a mode to manually match the delay on the PT2399 with the tempo on the Tap IC. I have another push button, that will be a microswitch on the pcb, that if you are pressing it, and have the time control at max and the multiplier at 1, you can tap at the same rate as the delay you hear, once it's set the led flashes 3 times showing it's saved. It saves the maximum time to the EEPROM on the IC, so that even after you switch off the delay, it stays set and you always have the tap in sync with the delay unit. I set the minimum to a hardcoded 25ms, so it might not be perfectly matched all of the way, but it's close, way closer than considering the maximum is 1125ms.
I've tried it with my rebote 2.5 delay and it works great.
Quote from: Galego on August 28, 2010, 01:00:12 PM
Well, i just finished the programming in my tap tempo IC (at least for now), don't know if anyone cares, but here goes anyway.
My version is quite more simple than what i have seen as i didn't really care about PWM (i did implement it at one point, but for now it's not working because i needed the input pin that used to be for the wave speed), also because i don't know what to do with it, my feeble attempts just resulted in a lot of noise from the PWM pulses.
I think the main feature i didn't see other people using is a mode to manually match the delay on the PT2399 with the tempo on the Tap IC. I have another push button, that will be a microswitch on the pcb, that if you are pressing it, and have the time control at max and the multiplier at 1, you can tap at the same rate as the delay you hear, once it's set the led flashes 3 times showing it's saved. It saves the maximum time to the EEPROM on the IC, so that even after you switch off the delay, it stays set and you always have the tap in sync with the delay unit. I set the minimum to a hardcoded 25ms, so it might not be perfectly matched all of the way, but it's close, way closer than considering the maximum is 1125ms.
I've tried it with my rebote 2.5 delay and it works great.
any chance this might be able to drive 2 PT2399s at different subdivisions but in sync?
waitting for advances
I've tried to contact Galego, but had no answer.
seems that i have to program tap tempo myself. I'm waiting for digital pots. one thing I don't know for now -- how to automatically sync tap with 2399, Gallegos idea to tap microswitch is not seems to be the best...
http://www.diystompboxes.com/smfforum/index.php?topic=86294.0
Have you seen that?
yepp. the only trouble is that I live in Belarus. You can read in news what is happening in our country right now. I'll have to go to the capital etc... so two chips would cost me about 70-80 bucks.
Hmm, I see. My understanding is that Galego does not like to post his code or schematics, so I wouldn't hold out for that.
This thread has some very useful info on this topic:
http://www.diystompboxes.com/smfforum/index.php?topic=87813.0
well, noone does. but he could told me that instead of being silent....
thanks for the link! Reply #63 was absolutely the same as I was going to do :)
Oh boy! Would i like to see this project rise? I think yes!
Pretty pretty pretty please Taylor! This sounds like the delay i always dreamt of having!
Unfortunately I'd need to start all over again, and realistically it's not something that will happen anytime soon I'm afraid. I would love to do this but work has been insane this year and I barely have a free moment.
I'm also not sure of the current status of any of those tap tempo chips. Looks like Taptation is in stock but I would want to verify that it will remain in stock for a long time before doing a board for it (otherwise we may end up in a situation with boards for chips that will never exist again).
Just so nobody gets their hopes up, I doubt I can work on anything like this this year. However, as before, if anybody does come up with a fully-realized and tested circuit, we could collaborate to get a PCB done and available for it.
Isn't the taptation just something you can plug in & play with the echo base?
Probably so, I honestly haven't checked out the Taptation, since when I was working on this project 1.5 years ago, the Taptation didn't exist. I was working with the PTAP2 which could control two separate delay chips so we could get polyrhythmic repeats and all that. I don't think the Taptation can do all that, but I could be wrong as I haven't read through all the threads and the datasheet yet.
But, this project wasn't simply a tap tempo EB in any case.
Quote from: Taylor on August 13, 2011, 04:19:35 PM
Unfortunately I'd need to start all over again, and realistically it's not something that will happen anytime soon I'm afraid. I would love to do this but work has been insane this year and I barely have a free moment.
I'm also not sure of the current status of any of those tap tempo chips. Looks like Taptation is in stock but I would want to verify that it will remain in stock for a long time before doing a board for it (otherwise we may end up in a situation with boards for chips that will never exist again).
Just so nobody gets their hopes up, I doubt I can work on anything like this this year. However, as before, if anybody does come up with a fully-realized and tested circuit, we could collaborate to get a PCB done and available for it.
It would be bloody nice to make a collaboration project out of this thing :) Care to share the current version of the schem?
There's no current version since I last worked on this over a year and half ago. Unfortunately I had a hard drive die last year and I don't think I have any of the files anymore. But it doesn't really matter because it would be useless now that the PTAP doesn't exist anymore. Something completely new needs to be done. Sorry!
I think it's easier for most folks to build something new than pick through another man's rubble in any case! :D I have no doubt that some enterprising person(s) will come up with something better at some point.
Quote from: Taylor on August 13, 2011, 07:54:23 PM
There's no current version since I last worked on this over a year and half ago. Unfortunately I had a hard drive die last year and I don't think I have any of the files anymore.
Sad! :icon_cry:
Yeah. I lost a bunch of stuff including a very intricate piano piece on which I had been working for a few years. That was the hardest.
The moral of the story: backup your files!