High Pitch Noise From Pro 10 Green

[DrVon]

I have a bit of a issue with my pro 10 Green build. I noticed at low volume there was a momentary pitch noise when moving the tone pot in one spot. Yesterday playing at louder volumes and stacking overdrives the noise was persistent.

Video and pictures in the link.

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I have replaced the tone pot, swapped out the opamps as I have a bunch. Re flowed all joints that I could access underneath the board. Removed the socket of Q2 and swapped in a new one as I thought the transistor was a little loose in the socket.

Any advice would be great.

 

[DrVon]

Just wanted to bump this as I'm still looking for any advice. I have tried isolating the power supply as I have one incoming 9v going to three boards. The issue didn't go away unfortunately. Would the buffer from the Kliche be causing this issue?

Also is there a schematic available? There isn't one in the build docs.

 

[Nostradoomus]

The first thing I would do have is shorten up any wire run in there that you can. Long wires are basically antennae. Anywhere you have an output signal crossing over an input needs to be cleared up, run them over and around each other, never one over the other. If this build is 3 gain pedals you may want to consider using shielded wire on the in/out jacks as well but try cleaning up the wiring first.

 

[DrVon]

The first thing I would do have is shorten up any wire run in there that you can. Long wires are basically antennae. Anywhere you have an output signal crossing over an input needs to be cleared up, run them over and around each other, never one over the other. If this build is 3 gain pedals you may want to consider using shielded wire on the in/out jacks as well but try cleaning up the wiring first.

OK will do. Do you have an example of shielded wire to use? I have some at work but it's used more for comms. Would you use a 2 conductor plus shield or a 1 conductor with the shield as the ground similar to a humbuckers?

Thanks for the response.

 

[Nostradoomus]

1 conductor for your hot signal and the braided shield to ground.

 

[DrVon]

1 conductor for your hot signal and the braided shield to ground.

Awesome thanks for the help. I will order some and report back.

 

[DrVon]

1 conductor for your hot signal and the braided shield to ground.

So I replaced all my audio signal wires to shielded and the issue still remains. Is there a filter cap within the tone circuit that could he the issue? There's no schematic for the board yet so I'm at a lost.

 

[Nostradoomus]

Did you try shortening/cleaning up your wiring?

 

[DrVon]

Did you try shortening/cleaning up your wiring?

Yes sir. I'm stumped. Even with the pcb on its own outside the enclosure the wiring for the input and output need to be very far away from the pcb itself to stop the feedback. Something on the pcb is causing the feedback. Using the schematic from the Nobels PCB document Im going to measure some voltages and grounds in the tone circuit. Looking at the layout the circuit around the 2N5088 seems to be the same on the pro 10. Or an educated guess.

 

[DrVon]

So it looks like I resolved the issue with changing out opamp 1 for a TL072 vs the 4558D as the tone circuit is in that opamp. It seems to resolved it but I will have to put it through it's paces. Thanks everyone for the help.

 

[music6000]

So it looks like I resolved the issue with changing out opamp 1 for a TL072 vs the 4558D as the tone circuit is in that opamp. It seems to resolved it but I will have to put it through it's paces. Thanks everyone for the help.

I was studying your pictures & I think your JRC4558D's might be fake.
All the ones I have purchased are clearly an off white printed lettering, these look more like engraving.

When ordering, look for NJM4558D and you should have a bigger selection to purchase from.
Were these from ebay, ali express, wouldn't trust them!

Here is what Mine have always looked like:

 

[DrVon]

I was studying your pictures & I think your JRC4558D's might be fake.
All the ones I have purchased are clearly an off white printed lettering, these look more like engraving.

When ordering, look for NJM4558D and you should have a bigger selection to purchase from.
Were these from ebay, ali express, wouldn't trust them!

Here is what Mine have always looked like:

View attachment 18764
View attachment 18763

It wouldn't surprise me. I had bought them from ebay (shame I know) when I started making pedals 2 years ago. Maybe I will try and order some like you have shown and give it another go.