Arc Klon v2 - Diagnosis of WEIRD NOISES

stickyfiddle

Hi all! Has anyone got one of these in the house at the moment? I've got a friend's one in for repair that was sounding crackly & weird at certain points on the gain knob's travel. 

I've given it a good bit of contact cleaner. It then made some *really* weird tremolo sorts of noises (I assume while the contact cleaner worked through and evaporated. But now sounds ok I think. 

My main question now is just whether the gain pot is always a bit less stiff to turn than the others? This was actually my pedal originally but I can't remember how the knobs felt. Not that it necessarily matters if all else is well. 

Any other thoughts also welcomed, obviously! 

Danny1969

From memory that pot is a dual gang so may well be a different brand from the others. Cleaning a pot always makes it looser in my experience ... some cleaners leave a lubricate after evaporating 

stickyfiddle

Cheers @Danny1969 that was pretty much my assumption. You're right that it's a dual gang on the gain, so even if it's the same brand I wouldn't expect it to be identical in feel

 There's still a slight crackle as you turn the knob but I have a feeling they might also all do that. I haven't compared with my Archer yet because honestly I don't remember where I put it!  

stickyfiddle

Ok contact cleaner didn't help and now it's back to making some fabulous dirty tremolo noises even worse than before. It gets faster as you turn the gain knob up. Also quite a lot of hiss at all times

Clip here... https://youtube.com/shorts/pPfVSFkCUpk?si=bL0m2BIAqQNRUFTd

@Danny1969 @ICBM @anyoneelse !! 

Danny1969

I can’t hear it at the mo as in opticians but would imagine it’s the chip that raises the rail up … 760 or similar 

Danny1969

Just had a listen and you have invented a great new effect

I'm assuming inside it's a regular Klon circuit ? if so there's only 3 chips .. 2 x TLO72 and the charge pump chip which is generally a 7660, 1044 or similar chip that doubles the voltage and inverts one half ... this is a CMOS switched chip and when it goes bad (normally because it's been reverse biased by the wrong power supply) it will create havoc on the power supply 

I normally just change all 3 chips as that cost less than £4 from CPC in sm form, a little more in thru hole and the decoupling caps near the charge pump chip as a precaution 

stickyfiddle

Danny1969 said:

Just had a listen and you have invented a great new effect

I'm assuming inside it's a regular Klon circuit ? if so there's only 3 chips .. 2 x TLO72 and the charge pump chip which is generally a 7660, 1044 or similar chip that doubles the voltage and inverts one half ... this is a CMOS switched chip and when it goes bad (normally because it's been reverse biased by the wrong power supply) it will create havoc on the power supply 

I normally just change all 3 chips as that cost less than £4 from CPC in sm form, a little more in thru hole and the decoupling caps near the charge pump chip as a precaution 

Yeah, it's a regular circuit AFAIK, and actually quite a musical effect if I'm honest, just not the one this pedal is meant to make!

I did think it felt like a voltage issue, so your description sounds very plausible given the charge pump etc. Should be an easy fix at least, assuming that's right.

DesVegas

Congratulations, you now have a tremolo, and a rather fantastic one at that