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Pedal Squealing

Donald Wormuth

Donald Wormuth

Jan 6, 2021
243
109
59
Waco Texas
#1
In my pedal chain, which goes Bass, Stax 5 band eq to Boss ODB-3 Over Drive to VoxstompLab IB muti-effect to Radial Big shot ABY to amps. My Vox squeals while under AC power. If I use battery power it doesn't at first thought it was daisy chain power supply. So, I bought an Isolated power supply. Stayed the same and I've tried every possible configuration. I still get same issue If it's not in chain by its self it doesn't do it. For the life of me I can't figure it out.
 
#6
My gut is telling me it has to do with the ABY causing some sort of feedback loop. If you remove the cable going to one of your amps that might isolate the issue. The only other thing I can think of is that there might be an issue with the stereo out and a bad cable or connection causing some kind of issue.

I feel like there's details missing that would make it easier to dial it in.
 
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#10
Donald Wormuth said:
Even if I remove the ABY it still does it. Both amps. If it was a feed back, it would still do it even with the battery correct?
Click to expand...
If there was an issue with some ground connection, that could cause an issue that doesn't show with a battery. Like an issue at the 9v plug that is supposed to disconnect the battery but doesn't or a reverse polarity cable or something. It is definitely a weird problem.
 
#11
Donald Wormuth said:
So, I bought an Isolated power supply.
Click to expand...

Some "isolated" power supplies...aren't really isolated. In addition, there are often paired outlets on isolated power supplies that aren't isolated from each other, but are from the other outputs. Can you send us a pic of your power supply, showing what connections you're using?

If it's a squeal that doesn't take over the signal path (gets louder than the signal) then it's not feedback - my bet is it's power supply related, which is verified by the fact that a battery fixes things.
 
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#12
Donald Wormuth said:
Even if I remove the ABY it still does it. Both amps. If it was a feed back, it would still do it even with the battery correct?
Click to expand...

The one time I heard a high pitched squeal coming out of a pedal that had a muted instrument plugged into it.. the pedal wasn't getting enough power. It had a high current draw of like 300mAh or something and he only had 200mA plugged into it.

It sounds almost like the power connection on the pedal might be damaged if you're sure you're feeding it enough current. I mean.. I could be totally wrong.

Is the battery access from the bottom? You could try the 9v adapter that 1-spot makes. I used one for a boss footswitch that only ran on batteries.

Truetone CBAT 1 SPOT Battery Clip Converter

*Edit* nvm.. just saw it takes 4 AAs.. I'm trying to find specs on the current provded by the power supply that comes with it.
 
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#13
micguy said:
Some "isolated" power supplies...aren't really isolated. In addition, there are often paired outlets on isolated power supplies that aren't isolated from each other, but are from the other outputs. Can you send us a pic of your power supply, showing what connections you're using?

If it's a squeal that doesn't take over the signal path (gets louder than the signal) then it's not feedback - my bet is it's power supply related, which is verified by the fact that a battery fixes things.
Click to expand...
micguy said:
Some "isolated" power supplies...aren't really isolated. In addition, there are often paired outlets on isolated power supplies that aren't isolated from each other, but are from the other outputs. Can you send us a pic of your power supply, showing what connections you're using?

If it's a squeal that doesn't take over the signal path (gets louder than the signal) then it's not feedback - my bet is it's power supply related, which is verified by the fact that a battery fixes things.
Click to expand...
Yeah give me a second I'm going to have to do it for my laptop every time I try to do it from my phone it won't upload for some reason
 
#14
I am having a really hard time finding the specs on the power supply designed for that pedal other than it's 9V, sleeve positive, and center negative.

*edit* According to a listing on amazon you want at least 9v 200mA current with that pedal, less than that could cause to make undesirable noises such as sqeualing.

*edit* more edit.. you should have been fine with your One spot and the daisy chain. Your combined pedal power doesn't come close to using that kind of draw.
 
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#15
micguy said:
Some "isolated" power supplies...aren't really isolated. In addition, there are often paired outlets on isolated power supplies that aren't isolated from each other, but are from the other outputs. Can you send us a pic of your power supply, showing what connections you're using?

If it's a squeal that doesn't take over the signal path (gets louder than the signal) then it's not feedback - my bet is it's power supply related, which is verified by the fact that a battery fixes things.
Click to expand...
 
#17
20210424_213154.jpg
 

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