Anyone has working keith raper circuit?

[sdman]

I've made the circuit and i will post photo and scheme here later. But the problem is: Even if i disconnect "switch" piezo, my module(megadrum) receives switch signal on strong hits. I mean if i hit not too hard, it works good )) But i doubt. I tried even 1M Ohm resistor instead of 100k to make "switch" piezo less sensitive. But the same result. Strong hits give second zone signal even with disconnected second zone piezo.I thought before that it is crosstalk problem, but it is not. Definitely. If this problem solved anywhere, you can tell me, i will search more for the solution. Thank you for your answers.

[dmitri]

My first suggestion would be to lower Threshold on the rim/edge input.

[sdman]

i tried, but it worked like it has crosstalk problems (but in fact, piezo's are not on the same surface). The point is that even if i disconnect edge piezo from the circuit, i got edge signals when i do strong hits on bow zone. But i get bow signals good, when i do soft hits. If i disconnect keith raper circuit, i normally get whole dynamic signals when i hit soft and strong on the bow zone.
I made the circuit several ways but with the same result. Here i show you the simplest scheme for the circuit i made(with votage divider on main piezo). And sorry for this unusual scheme.

[dmitri]

Looks like that the way you built it introduces electrical crosstalk. When you disconnect a piezo from the edge input you in fact make it worse since the unconnected circuit on the base of the transistor becomes an antenna. Also, to make it less sensitive you actually should decrease the R value.
And still I suggest you to lower Threshold. You can even start with Threshold 0 (it shouldn't trigger at all) and work up from it.

[sdman]

ok, if disconnected piezo can get this worse, i have to try circuit with totally separated surfaces for both piezos ) actually i had to try it first ))

[sdman]

ok, it was definitely physical crosstalk problem )) i connected other cymbal as edge piezo and that way the circuit works correct. (2 cymbals are connected to one piezo-switch input). But actually i have 2 surfaces for bell zone and bow zone. There is a foam tape between zones. So if this way does not work idk how surge and other metal cymbals work ) Because there is only one surface. And i doubt that only special material tape helps to isolate piezos )