amek m2500 eq Q pot...

electrichild

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[quote author="12afael"]check your wiring an values. it shouldn`t oscilate.

what op amp are you using?[/quote]

Checkin the schems and your version (amek+harrisonFV2) in your old posts I found a little difference in the position of R11 1k (original schem) that is between pin2-C4 and R138 freq pot and your R6 1k that is between freq pot and pin7: can this cause the oscillation???
Other issue is extreme distorsion applying the maximum gain...
I'm using TL074CN opa
I retry check tomorrow

Thankz
 

12afael

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I don`t think so, it is just a variable resistor.
check your resistors if you have extreme gain an error there could be the problem.
 

electrichild

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Checking the circuit I found a bad solder point between the capacitor trough pin 1 and 2. All seems ok now but I notice something strange: after few minutes of properly working there is a drastically change in the level...too low. I retry powering up and all it's ok and again the level drops...
It's a long way...
 

12afael

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mmm is not so easy without a scope. The IC is unusually hot? maybe try a polyester cap between the ic supply pins and ground.

this is more a question than an answer, it`s possible to rectify the output and measuring DC to verify high-frequency oscillations?
 
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