Harmonic Multiplier

[dubiousss]

OK just built http://www.lynx.net/~jc/pedalsHarmonic.html this,

What transistor should i have used (3904 is in there but i dunno?)

Also didnt really understand the nulling instructions, whats the tuning set im supposed to disconnect?

[Eb7+9]

any generic small-signal transistor will work here as a current source - 3902, 2222, 5210, 5089 ...

for tuning compare with original instructions :




In the Harmonic Multiplier circuit the first op-amp is serving as a (better) buffer to the four input paths (A,B,C,D) - they operate in two groups of two if you compare to the EMS design - note that the first op-amp also works as buffer to the linear mixer, that's three birds with one op-amp  ... there are two inputs in a Balance Ring Modulator, and the circuit is nulled while sending signal to one input group at a time - ie., through either path groups B,D or A,C ... one path group is left open during the testing of the other ... in the HM schematic I'm suggesting a disconnect on the side of the multiplier but it makes no difference which end of a circuit "branch" is disconnected ... we don't need a sine wave to do the nulling either, a gtr signal will do - you'll hear the circuit clean up at the null positions ... don't forget to raise the bottom rail to -7.5v from -9v (that what the two silicon diodes are for) ...

-> Harmonic Multiplier schematic

[dubiousss]

thanks man