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anybody know how to do the lo/ hi tom pitch mods on a tr606

Started by selfpreservation, September 27, 2010, 09:00:03 PM

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selfpreservation

hi i know its not strictly circuit bending but does anyone know how to do this i can find all the other mods for the tr606 online but not these

Gordonjcp

Look at the circuit for the tom oscillators.  See the two resistors associated with Q307 and Q308?  They set the pitch (and to an extent, the decay time).

As C808 (? can't read the diagram clearly) discharges, the voltage on the bases of these two transistors decreases and they conduct less.  When they are fully conducting they pretty much short out the resistor across them, so the filter frequency is only set by the resistor "above" them.  When they are fully "off", the frequency is set by both resistors in series (R333 and R334, for the high tom).
If at first you don't succeed, stick it through a fuzzbox.

selfpreservation

cheers for your help gordon but i dont really understand what your mean :-\ , i can see where you mean on the diagram but i still dont understand how to add a pot to change the pitch of the individual toms im afraid i just dont have the technical know how to interpret your instructions  :-[