Too much squealing/feedback when paired with poweramp

Hey all,

I’m having an issue with my quad cortex and having an insane amount of feedback from my power amp/cab. Any time there is a pause or tight stops/starts in our music, you can hear the amp just screaming. It’s obviously frustrating when trying to have nice tight pauses, etc.

My setup consists of a QC (running a fairly basic patch of a Friedman amp, two gates, one on the input at the start of you chain and one after the amp block, sometimes I’ll throw on a green 808 but that usually when I’m just screwing around), and orange pedal baby and Mesa Trad 4x12. I have great tones built and I’m getting the sound I want. But I’m hesitant to not run this setup anymore due to the amount of unwanted high pitched squealing going on. I’m standing 12 feet away from my amp so I’m definitely not close enough to cause this. Gates are on, pickups really aren’t that hot, and we are loud as a band, but my previous tube amps never made this kind of unwanted feedback during playing. Am I missing something here? If anyone can steer me I. The right direction that would be awesome. Thanks and sorry for the long message.

Happy new year!


The orange pedal baby doesn’t have tubes so tube microphonics are out of the way.
Next thing to check is wether the squealing happens when you turn down you guitar volume.
If the squealing stops on guitar volume down, I’d bet your pickups aren’t wax potted or aren’t wax potted enough.

Here’s the first YT video I found on wax potting in your garage : How To Wax Pot Guitar Pickups - YouTube

Thanks for the reply @thomasotto

The strange things is that I’ve used multiple guitars with different pickups. Both active and passive. My amp tech has told me that it’s just simply too much gain. I’ve run different paths on patches that involve dual amps, with overdrive pedals to tighten in up. Even as much to add up to 3 gates haha. Messing with the I/O levels. I’m just so confused on why I can’t make this thing stop screaming. I will definitely looking to the the wax potting as well.

Hey @BEABS ,
If you tried with active & passive guitars, then maybe the wax potting isn’t the issue (unless both of them don’t have any wax).
If your tech says too much gain, he might be on to something…

You might be facing a dilemma :
1 - you need all that gain : put a volume block to 0db (towards the end of the chain) that you can switch on when silence is required (like a mute switch). Maybe a momentary switch on the expression input (like a kill switch).
2 - you can live with less gain : turn the drives and gain down to a level where the guitars won’t squeal.

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This problem can pop up with any modeler. I have definitely run into it before. My guess would be that either your input or output settings need to be dialed back or a level in one or multiple blocks in the preset is too hot.

I might try examining and then lowering the input or output gain if necessary. Move through your blocks and dial back level/gain settings.

Some blocks though, do tend to lend themselves more easily to this kind of thing. If parameter changes don’t help, another amp/pedal combination might just be the ticket if you can’t eliminate it.

EQ spikes (intentional or otherwise) somewhere in the signal chain can exacerbate feedback.

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Not sure what I am talking about here, but I have had that kind of issue when having the line/Instrument switch in the wrong setting.

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I recently had a similar situation. I had my set up on an A/B switch to compare a capture I made to the actual amp.
I was running the capture through a SD solid state amp.
PS: I agree the captures always are noisy relative to the real deal. Very noisy.

I noticed tremendous feedback and squeal with the capture and none with the real amp.
I then turned down my tone knob (which was on 10) and it went away. I believe the D style power amps are more prone to high pitch squeal.
My next test will be to compare the same capture through the SD solid state power amp and then through the tube power amp using the Return on the loop. This way I can use the same QC capture and isolate if it’s the Power amp or the QC.

Today tryed qc amps (only one block, without cabs) ) with ehx magnum 44 class D in Marshall 2x12 st212 with greenback 65. Not so good result…
Seems that qc Is a Beast in the box…but with this cfg…not.
My impression, usable tones but very far from a real amp and a sound without Life.

The magnum 44 isn’t a great power amp. It starts to saturate quickly and colors the sound way too much. The wattage is super low so it has no real headroom for reproducing low end well, aside from maxing out by halfway on the knob volume wise.

I tried a Magum 44 recently to use as a backup, and it was really weird sound wise.

I would highly reccomend a Seymour Duncan powerstage 200 or 700. 200 is nice since it has the additional presence control and the eq knobs are centered more around frequencies for guitar. I use a powerstage 700 since I have an orange 212 that’s 16 ohms. Most of the solid state power amps are rated for their output at 4 ohms and immediately are half that at 8, and again at 16.

With real mesa quad preamp or studio preamp , the 44 was really good, or DIY preamps in my experience.
I Hope that it’s as you said, because the sound Yesterday was weird :weary:

Are you using a capture of a preamp or a full amp model in the QC?

All solutions…several qc amps head with the 44.
With Headrush was super fun, but here QC seems cut the band extremes and the mids are without Life compared a real amp.

Tried Yesterday only Overdrives with qc and hx effects in real amps

In the box i prefer QC overdrives sounds, but with real amps and digital overdrives (qc and hx) …hx wins and this Is really strange. Qc introduces a lot of mids and the sound Is thin

All in the box the opposite. Qc sounds beautiful. Strange imho

Magnum 44 was ok with my rig in the past…
But as you said…no good with qc.

Tryed Better with carvin t100 and qc sounds awesome. Obiouvsly Better with preamps captures as amps. Wonderful sound.

The carvin also Is a Beast…and i’ m searching easyer rig.

What do you think A /B pa as pedal baby (Orange) or powerstage 170?

Powerstage Is good without coloring the sound? (Use with qc amps)

Thank you for eventual confirm