OTA tremolo issue

[fuzzo]

hi,

I'm working on an OTA tremolo pedal , for now , it's all made on my breadboard but I'm experiencing two big problems and I can find any solutions .

1/ Everytime I make a I/C oscillator (integrator and comparator) I have a big  "clock" noise  in the audio path , even if any audio is plug in .  the strange fact is I recently made the KMD phaser LFO on the same breadboard (with the same power suply) and it was really quiet , any clock noise. So I'd like to know what make it so noisy and impossible to use in my situation . I tried several things but nothing calm down the noise , is it particular to that circuit ?

2/ I've an excessive background noise coming from the OTA , (like if the volume was cranked  up ) , I tried also différent things , playing with the Iabc resistor or with the input resistor , nothing change. It's the second time I'm working on it , and like in the first one I've that noise .

Do you know how I could sove that two issues ?

   

[R.G.]

There is no way to tell without knowing the circuit you're working on.

Phasers and tremolo are different.

OTAs have noise problems, very often because the input has to be attenuated down to about +/- 25mV at the inputs.

[cpm]

¿what is your schematic?, i took RG's directions in OTA tremolo, and got it working quite noiseless

[cpm]

i think the key here is lower the resistor that makes current-voltage conversion ant the OTA output

[fuzzo]

thnaks ofr the answers.

you're right it'd be easier with the schematic 

here's the LFO i'm using :



(from Ken Stone's  synth website ) .

I'm just using the two first AOP and changed the cap in the feedback loop to 100n to have a larger range .

But actually I've the noise with every component value with this kind of LFO , it's not particular to this LFO  .

¿what is your schematic?, i took RG's directions in OTA tremolo, and got it working quite noiseless

I also took the rg's directions for the OTA .