Taptation with tandem PT2399s?

[Leevibe]

I'm wanting to build a delay with long delay times that I can also control with tap tempo. Is it possible to incorporate tap tempo when two chips are involved? If so, how do I implement it? I'm thinking ZPDD when the boards are in. Where would I tie in? At the Q1/Q2 junction?

[midwayfair]

The taptation controls a digital pot. The pot with two PT2399s is hooked up to a current mirror, which controls both chips simultaneously. The Taptation works just fine for the basic setup.

What the taptation most likely will NOT work with is an external modulation circuit wiggling the digital pot, because the modulation might reset the chip and let the soft takeover, well, takeover. Your tapped tempo goes out the window I suspect. In that case, you'd have to get your modulation from the taptation itself.

There's a huge thread on adding the taptation to the zero points.

[Leevibe]

The taptation controls a digital pot. The pot with two PT2399s is hooked up to a current mirror, which controls both chips simultaneously. The Taptation works just fine for the basic setup.

What the taptation most likely will NOT work with is an external modulation circuit wiggling the digital pot, because the modulation might reset the chip and let the soft takeover, well, takeover. Your tapped tempo goes out the window I suspect. In that case, you'd have to get your modulation from the taptation itself.

There's a huge thread on adding the taptation to the zero points.

Thanks Jon. After reading through all of that, I think it makes more sense to stick with a single-chip circuit. In practice, I don't use tap for long delay stuff anyway. I think I just need a well-filtered PT2399 circuit. I built up a GPCB D'lay and it's... OK. I should probably audition a couple chips in there. I may have a clinker. I like a little grunge and grain, but it's pretty noisy.

I'm planning a multi that's going to be kind of a fly board type thing and I would like the delay to be fairly versatile, to the point that I could even use it with acoustic. That's probably pushing it for a single PT2399, but tap is essential for me if the delay is to be used for multiple situations.

[jkokura]

I can confirm that the Taptation does not work for multiple PT2399's in series via the pin 6 trick of a standard PT2399. Andrew never designed it to, so it doesn't work. Nor does it work to control a dual digital pot, which is what I tried to make work.

What you can do is run multiple Taptation circuits from one switch. In other words, you can run two taptation chips, two digital pots controlling two analog pots, and run a dual PT2399 setup that way. The hazard is that you NEED to have synced Digital pots, and that's more challenging. It's not hard to find a digital pot that's close to accurate, but finding a matched pair is more difficult, and might be costly.

Jacob

[Leevibe]

Thanks for the input guys. Now I'd like to derail this thread toward opinions on clean(ish) PT2399 delay circuits. I will implement a taptation board and I'm open to using taptation based modulation or on-board modulation as long as I can control the depth with a pot. I don't want one that's overburdened with controls because I plan to put it in a multi. The controls I'm planning for are: time, feedback, mix, mod depth, 1/4 & .1/8 switch, 1x/2x speed switch. Did I just contradict myself? Tap will be via an external switch.

[jkokura]

It sounds like the Hamlet+ is pretty much what you're looking for...

Jacob

[Leevibe]

I've thought about it. It would save me buying and fiddling with a daughter board.