Phase II - High Pitch Noise - Even when bypass is engaged

unicursal

unicursal

New member
Hey folks,

I just finished building the lovely Phase II and everything works great functionally — the effect sounds awesome!
However, I'm experiencing an issue: there's a high-pitched noise present even when the pedal is bypassed.

Here's what I've tried so far:
  • Double-checked all component values
  • Reflowed/resoldered all connections
  • Swapped out cables and tried multiple power supplies (including isolated ones like my Cioks 7)
Unfortunately, the noise is still there.
Has anyone run into a similar issue or got an idea where to look next?

Thanks in advance for your help!

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That was fast! Thanks for the helpful suggestions!

I’ve now rerouted the input and output wires underneath the PCB, unfortunately, the high-pitched noise is still there.

I'll attach a photo of the charge pump IC so you can take a closer look. Maybe it’s not the right type or a noisy/counterfeit one, as you mentioned.
Appreciate the support!
 

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It's the right IC model at least. But the soldering looks like it could do with a re-flow. Look at the square pad on B10k, it doesn't look it took hold well. If it's like that in other places, then that could also be the problem.

If you have another charge pump IC, then try that. 7660S should work as well.
 
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Where did you buy your charge pump (IC7) from?

Normally, to determine if it is a bad charge pump whine you would remove IC7 and work off of 9V. However, this design derives its Rref and IC power return from pin 5 of the IC, so if you remove the charge pump it won't work at all.

Charge pump whine is typically experienced as a high frequency ring that is the sub harmonics (typically around 14Khz and 7Khz) of the switching frequency (typically 28Khz). Occasionally, it can be mitigated by a 0.1uF metal film cap in parallel with the slower C16 220uF electrolytic cap. But most times, settled with a more reliable brand charge pump IC (ICL7660CPAZ, or the 1040S from PedalPCB, Mouser and don't trust the Amazon or Temu ones, unless you are a gambler).
 
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Thanks again everyone for your help!

I just reflowed all the solder joints carefully. The charge pump IC came with the Phase II kit from Musikding, so I assume it should be a reliable one, but I know that’s not always guaranteed.

The high-pitched noise is still there, unfortunately.
 
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