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

[Galego]

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?

[JKowalski]

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

[Beo]

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

[Galego]

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?

[Taylor]

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.

[Beo]

Sure, I understand Taylor. If I get a design matured, I'll share it here so that others can help critique or improve it.

[Galego]

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.

[aziltz]

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?

[Dr.maligno]

waitting for advances

[vavan]

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...

[Taylor]

http://www.diystompboxes.com/smfforum/index.php?topic=86294.0

Have you seen that?

[vavan]

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.

[Taylor]

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

[vavan]

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

[askwho69]

VERY EXCITING

[grrrunge]

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!

[Taylor]

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.

[Valoosj]

Isn't the taptation just something you can plug in & play with the echo base?

[Taylor]

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.

[grrrunge]

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?