FX Loop feedback - Squeal from hell

RVA

RVA

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Mates,

When I hit my boost/eq pedal with the boost cranked and a gain pedal on out in front, I get a nasty high-pitched squeal.

I am not trying to diagnose the problem. When I lower the boost in the loop or decrease the gain on the pedal in front, it disappears. My question is why it presents itself as a consistent high pitch squeal and if it can be fixed without lowering the boost or gain. Thee is no oscillation or pitch change, just an ear piercing squeal,

Thanks for any guidance
 
RVA said:
Mates,

When I hit my boost/eq pedal with the boost cranked and a gain pedal on out in front, I get a nasty high-pitched squeal.

I am not trying to diagnose the problem. When I lower the boost in the loop or decrease the gain on the pedal in front, it disappears. My question is why it presents itself as a consistent high pitch squeal and if it can be fixed without lowering the boost or gain. Thee is no oscillation or pitch change, just an ear piercing squeal,

Thanks for any guidance
Click to expand...

I recently experienced this running my low impedance Boss F30L in the effects loop....BUT...it only squealed when rolled OFF!!!!

I still haven't figured it out....
 
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Guitar amp FX loop noise

https://www.thegearpage.net/board/i...h-true-bypass-loop-pedals-please-help.147153/

A solution posted:

Oh my god I figured it out and LOL @ what is going on.

Okay so I've got my DC brick that usually powers most everything on the board but it only has 7 power output jacks and I have more pedals than that so I got a one spot (used to have one and worked great but got lost somewhere) and had been using that to power a couple pedals.

Now, again, NO idea why this just happens to be happening now but basically if the one spot is powering both a pedal in the loop and a pedal in front of the amp, I get that squeal.

If I have just the one spot powering all the loop pedals and the DC brick powering the pedals to the front of the amp, everything is fine. The minute I plug one of the onespot plugs into say the wah or od pedal, boom. Squealing.

Can anyone explain what in the hell is happening?
 
Robert Herndon said:
Guitar amp FX loop noise

https://www.thegearpage.net/board/i...h-true-bypass-loop-pedals-please-help.147153/

A solution posted:

Oh my god I figured it out and LOL @ what is going on.

Okay so I've got my DC brick that usually powers most everything on the board but it only has 7 power output jacks and I have more pedals than that so I got a one spot (used to have one and worked great but got lost somewhere) and had been using that to power a couple pedals.

Now, again, NO idea why this just happens to be happening now but basically if the one spot is powering both a pedal in the loop and a pedal in front of the amp, I get that squeal.

If I have just the one spot powering all the loop pedals and the DC brick powering the pedals to the front of the amp, everything is fine. The minute I plug one of the onespot plugs into say the wah or od pedal, boom. Squealing.

Can anyone explain what in the hell is happening?
Click to expand...
I saw that. I am powered by Voodoo and T-Rex isolated power supplies. Also, for me it is a function of excessive gain and boost and goes away if I decrease either.
 
My EF86 VOX AC-15 build guitar amp no effects loop, if I go over 2 on the volume it's out of control with boost peddles. What's going on is your hitting the input or front end with a gain factor of over
a million times normal. A EF86 has a gain factor of 180 a 12AX7 has a gain factor of 100 so if you use a 12AX7 don't turn up your amp volume over 4 should be OK.
One more point I don't turn up the gain on my boost peddles more than 50% or they squeal. I only use non potted pickups
 
67plexi said:
My EF86 VOX AC-15 build guitar amp no effects loop, if I go over 2 on the volume it's out of control with boost peddles. What's going on is your hitting the input or front end with a gain factor of over
a million times normal. A EF86 has a gain factor of 180 a 12AX7 has a gain factor of 100 so if you use a 12AX7 don't turn up your amp volume over 4 should be OK.
One more point I don't turn up the gain on my boost peddles more than 50% or they squeal. I only use non potted pickups
Click to expand...
Thank you. That really gives me an appreciation for how hard my amp is working
 
67plexi said:
My EF86 VOX AC-15 build guitar amp no effects loop, if I go over 2 on the volume it's out of control with boost peddles. What's going on is your hitting the input or front end with a gain factor of over
a million times normal. A EF86 has a gain factor of 180 a 12AX7 has a gain factor of 100 so if you use a 12AX7 don't turn up your amp volume over 4 should be OK.
One more point I don't turn up the gain on my boost peddles more than 50% or they squeal. I only use non potted pickups
Click to expand...

Interesting!!!!!!!!!!!
 
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