Tap tempo modded Echo Base PCBs in the works - vote on features

[Beo]

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

[Taylor]

Hm, interesting. I will check into it further. Would be cool to get this project going again.

[jkokura]

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

[Taylor]

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.

[jkokura]

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

[Taylor]

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.  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.

[Beo]

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).

[Taylor]

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.

[dmc777]

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.

[Taylor]

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.

[Taylor]

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.

[Skruffyhound]

Glad this project is moving again, still following with interest.

[azrael]

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...

[Beo]

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

[Taylor]

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.

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.

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 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.

[Beo]

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.

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

[Taylor]

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.

[Beo]

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?

[Taylor]

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)?

[jkokura]

Not I said the Jacob.

Jacob