Klon Centaur clone sounds weird

[DocBrown]

Sorry, this message is a missclick

[antonis]

what do you mean by "DC isolate" ? put some shrink isolant ? English is not my primary language...

Neither mine, so we have a long way for coordination..
(just kidding, of course)

By "isolation" I mean a capacitor for blocking DC..
(a non-polarized cap of 470nF, or bigger, should be fine..)

[DocBrown]

Ah ah we will figure it out 

Thanks for your explanation that's way more clear now. Just to understand well, the cap you suggest to add is to cure the problem or to find what is the problem?

So I have to put the cap between R10 and the pot lug I'm I right?

Thanks again.

[DocBrown]

Sorry missclick again. Need some sleep...

[willienillie]

The squeal might be oscillation due to excessively long and/or poorly routed wires.  That oscillation might still be present at ultrasonic frequencies after the audible portion goes away, and messing with your dirty sound.

It's good that you socketed your clipping diodes, try several pairs, they will make a significant difference.  I ran wires to my breadboard and tried about 12 sets when I built mine.

[DocBrown]

Thank you.

I must admit that wires are the part I'm not really proud of. This is another difference from the original refractor design. I made the pedal in a bigger enclosure so I must use wires to plug the pots.

I also think it could be a bad chip or a bad pot? I also spot some solder joint that would be better if redone.

[antonis]

If you trace IC1B out through R12, R11, R10, Gain pot wiper and R30 you'll see that there isn't any DC blocking cap inside particular NFB loop, so DC is also amplified by stage closed-loop gain..
(and not rolled-off to unity..)

[DocBrown]

thanks a lot.

So this morning I try to optimize routing. Make some wires shorter etc. Things are way bettter. No oscillation anymore even if you can feel it's really close when the gain is over 3 o'clock. There is a few stuff I can do better (make gain pot wires shorter for example). I thing it will cure the problem.

I keep the blocking cap idea in case optimized routing is not enough.

Thanks a lot for your help !!!

[DocBrown]

Little question gentlemen :

is using shielded wire for in / out wires and wires of the gain pot a good idea for reducing the oscilation ?

Thanks a lot.

[antonis]

It shouldn't improve anything but it couldn't do any harm either..

[DocBrown]

Humm... Anyway it's probably a routing problem. I made try a few days ago and the oscillation was stronger than before. I shook the box a little and it, as way better. Nobody moves on the board so...

Is there any documentation about how to run wires properly? Obviously I know the rule "the shorter the better" but there is probably other stuffs to do or to avoid.

Thanks a lot!

[keyth72]

I know this is an old topic and probably not relevant for the original poster, but in case someone new has this problem..

I also had a high pitch squealing sound from my Klon clone (pedalPCB Kliche mini) and it was related to the charge pump ICL7660/TL1044 (I had a TL1044). The squealing went away when I grounded pin 7, which is the oscillator.  Not sure if the chip is now acting as is supposed to or not, but the pedal sounds good and it didn't have any more noise.

[antonis]

I grounded pin 7, which is the oscillator.  Not sure if the chip is now acting as is supposed to or not

https://ww1.microchip.com/downloads/en/DeviceDoc/21348a.pdf
page 5..

[zbt]

Hi Doc, if you don't mind, could you test IC2 TL072 with a better chip like OPA2134

1. it test chip if is it bad
2. it test if because IC3 (charge pump)
3. also if there is improvement to sound

Thanks