High-pitched squeal from amp - with gain and volume

I just thought of something as I was Peeing, Believe it or not.

I remember hearing a high pitched squeal from my Amp when I plugged my TS9 in and had a POWER SUPPLY not 9V battery.

It turns out I had a reverse polarity Power supply. It was sleeve grounded when my effect needed tip ground or vice versa,
Has anyone mentioned this?
 
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RVA said:
Mates,

There are a fair amount of threads on this topic out there, but my combo of circumstances is a bit different, so I thought I would ask.

I have a loud, whistling-type, constant feedback when on the clean channel and using high gain pedals
- when there is medium to high gain
- with high volume for this 20W amp
- that is NOT reduced by turning the guitar volume all the way down
- that is NOT reduced by walking approx 25 feet away
- that is NOT reduced by touching the strings
- that DOES breifly go away when actually attacking the strings while playing
- that DOES go away with amp volume reduction (either master or channel)
- it DOES reduce when I turn off delay and reverb

The pickups were stacked Tom Anderson P90s and they are generally dead quiet. The noise does not change when pickups are split or both coils.

It seems that the simple answer would be that it is not the guitar and that this amp simply feeds back with gain pedals at high volume. A less likely thought would be that one or more of the preamp tubes are microphonic.

It is preventing me from using some of my favorite pedals at higher volumes. Any help is greatly appreciated.
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See the last couple sentences, Dave
 
So it feeds back when you have a high gain pedal running through a decent amount of gain on the amp?

Well that's not very surprising. I don't bother with gain pedals on my 6534+ ... anything more than just a clean boost and it squeals. There's already plenty of gain in the amp itself
 
Dave Sloven said:
So it feeds back when you have a high gain pedal running through a decent amount of gain on the amp?

Well that's not very surprising. I don't bother with gain pedals on my 6534+ ... anything more than just a clean boost and it squeals. There's already plenty of gain in the amp itself
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Yes, but this was squealing with no guitar in the equation
 
chilipeppermaniac said:
Thanks, Ivan read away, LOL

This explains a lot in so few words. My suspicion is almost confirmed if I understand the picture on the 2 DC power supplies I have to be an indicator. The Danelectro is the same symbol as the back plate of the TS9. It shows center - View attachment 10190
ac-adapter-center-neg-gif.10190



My 9V 1000 mA is as you say. That DC power supply shows a + center.

I sure do learn my lessons from my lack of knowledge. Somehow I learn way way way more than I ever expect, all due to simple details like not knowing different supplies have their polarities reversed and I need to be extra careful to make sure both the device and the power are an exact match.
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HAHA Like a Mirror Image. Here is my post #53 in my TS9 Thread.
 
Tony M. said:
I know this is completely out of left field but could
it be a power problem in the pedal chain?
Are you using isolated power supplies for the pedals
involved or is there a daisy chain in there?
Click to expand...

YUP Tony, I saw it. Your reply was likely why I asked Ray to check if he had other amps he could check to see if it still occurs with. This would eliminate his amp(s) and then point to his pedal(s) situation.
 
RVA said:
I got the usual noise you would expect with ahigh gain pedal and the channel volume and master dimed with the guitar plugged in. I got silence with no guitar and channel volume and master dimed.
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RVA said:
I did this with the prevopisly offending pedal only and all was good. Now I need to find the problem pedal
Click to expand...

Ray, My suggestion is simply this from here on.
I know you are looking for the "offending" pedal, so basically if you don't want to physically undo all of them and look at the pic on the underside to verify Power Supply Polarity of all of them, then simply unplug one pedal at a time, turn things on and see if you get squeal. If so, replace that pedal and go to the next and so on and so on.

Believe it or not Ray, I believe it is quite possible you will find one of these in your pedal that is causing the squeal if indeed we do narrow it down to a pedal.

tube-screamer-melted-part-jpg.10179


tube-screamer-melted-2-gif.10182
 
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What is that? Bad diode?

I will start by getting a 9 v adapter with a healthy amperage and use it in pedals that are daisy chained
 
Yup Ray, This likely happened when I plugged in the Power Supply that was backwards polarity.
Once I put a battery in the TS9 Pedal, it would light up, but normal guitar sound would go away when I clicked the switch on.
Squeal gone with Battery. Then the forum informed me there was such a thing as matching polarities of these effects and Power supplies.
 
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