[sdiy] DIY TR909 : noise !

[Jörg Schmitz]

Hi,

for clarification : of course the noise level is set to 0, and I also tested the circuit with not inserted noise-generating opamps 7 & 8. No change, the hissing noise is there. As I said, it is a very very low noise level, but it is audible and I dont like it.

greetings, Joerg



>at last I have managed to built my own TR909 - bass drum pcb. It works prettty well (see >http://www.analog-synth.de/synths/tr909/tr909.htm for details), but I found one problem :
>the output is a bit noisy. You can hear a little hissing noise, which seems to correspond to >the envelope and therefore VCA activity of the VCA between the output amplifier and >distortion diodes (controlled by "decay").

>What would you suggest to eliminate that (not very loud) noise ? (Of course, this is not the >noise of the noise generator, bleeding through somehow, this is tested...)
>Another opamp for the output-amplifier ? Something better than the TL072 ? Something >better than the BC549 for the VCA's ?

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