Small Clone Chorus - Only Background Chorus

[hatdephurba]

Hi to all the Diy Comunity,

I built this small clone based on the schematic by FP, the last version of it.

My problem is that i hear the guitar signal very distortioned when it has to be clean, and a big chorus on the background, but no guitar with the chorus applied, i check every resistor value (i´ve read a post of a 120k bad value) , capacitors , every thing, all tracks too.

Ive change only the pnp transistor with 2n3906 and the npn´s with 2n3904.

I very lost on this one, if anyone has a clue that let me check other zone of the board , please let me know.

Thanks
Marcelo

[hatdephurba]

 

[KerryF]

you cant change PNPs with NPNs.  Get the right transistors and maybe it will work.

[H.Manback]

He didn't...

I do wonder, are those transistors the recommended replacements for whatever you replaced? There are lists of transistor types with their equivalent types, at least my regular parts shop has a book like that. Maybe those transistors are very different from what is supposed to go there?

Also does the trimpot have any effect?

[hatdephurba]

I read in the tonepad page, in the build reports a lot of people replace those transistors with the ones i put,  pnp´s 2n3906 and the npn´s with 2n3904.

When i adjust the trimpot a sound that i can hear in the background goes smaller and then a little louder.

Marcelo.

[H.Manback]

Then my guess is your input buffer is not working properly. Try using a audio probe on the output of the first opamp (pin 1 of the 4558). If that is heavily distorted, check the resistors of the buffer (the 33k and 6k8, and maybe the 220k and 1k). If those are correct, maybe it's the input cap or the opamp itself.