Recommendation on Op Amps please and Problem with Distortion Loop

[Guitarist335]

I am looking to utilize Op amps to build guitar pedals (distortion, overdrive- things of that nature).

I bought some through Amazon and they seem to be defective. 

Preferably looking for an assortment, and preferably through Amazon. Does anyone have a recommendation/link to such an assortment on Amazon? 

Thank-you

[EBK]

...they seem to be defective. 

What makes you believe they are defective?

[Guitarist335]

Used a socket.  Popped them in. Some work, some don't.  Same circuit.

[Guitarist335]

Common problem.  Sound is clean. No distortion. I should have explained this better. I am getting a clean sound, rather than the expected distorted  sound. I attached the schematic i am using,. although I am using a different op amp and have mapped the pins according to the op  amp i am using.

[antonis]

Check first for proper distortion configuration..
(it's rather weird for an op-amp to work fine at unity gain while been defective..)

P.S.
A schematic of particular distortion circuit would be helpful..

[Guitarist335]

That is what i need help with. What can of tests can I perform to determine what is causing this op amp not to produce distortion?

[antonis]

No op-amp produces distortion by its own...

On what particular circuit you "tested" them..??

[Guitarist335]

I posted the circuit above, in a previous post

[antonis]

Yeapp.. just realize it..

But this very particular circuit reminds something..

Could you plz quote relative thread..??

[antonis]

Don't bother.. Just found it..
https://www.diystompboxes.com/smfforum/index.php?topic=124859.0

You see, it isn't very polite to leave an incompleted thread (in which some guys tried to help you..) and open a new one unleashing your personal aspect..

Anyway, could you plz tell us where in the heck is C28 connected..??
(in case of your answer will be something like "nowhere" just don't tell it to us and simply connect it to any convenient GND..)

In case of your answer will be "on ground (AC or DC)" verify Gain pot isn't set all the way down (left) or shorted somehow..

[GGBB]

I posted the circuit above, in a previous post

That's your effect circuit - when you "test" an opamp using that circuit you rely on the correctness of the circuit as well as all of the connections. If something doesn't work, you can't be sure that it's the opamp and not the effect. To test whether an opamp is functional and not broken, keep things to an absolute minimum. Try this for passing audio:

[Guitarist335]

I have always appreciated everyone';s advice and have been polite with every post. This thread started as my asking for advice on where to find a good assortment of op amps. But then someone asked me why i thought my op amps were defective,  it opened this discussion as I did not want to ignore that person's question . . I did not ignore the other thread and the advice there.

Having said that, thank-you for both your suggestions. C28 goes to ground /. pardon me for answering in that way, but i am a newbie to this and that is the only way i know to explain. I connected C28 to the negative rail of the breadboard. The connection ran off the page of the original schematic, so i had to assume that's where it went.

I will try the way suggested of testing my op amp.


P.S. And I changed the title of this thread to include and Problemn with Distortion loop, because someone suggested to make thread titles descriptive. And as this one took a different turn than what i imntailly intended, i updated it

Sorry- i just noticed your other question. I rotated each of the pots, and did not get anything different.

[willienillie]

Well I think that by now, you are surely late for band rehearsal.

[antonis]

Most of breadboards need shorting between 5hole groups..
So check continuity between supply GND and C28 lower leg..