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FM3 feedback with high gain (headphone version)

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Jarick

Experienced
I'm getting some feedback with high gain, especially when using some kind of boost. I’ve swapped guitars, changed firmware, changed amp models, and its persistent. It may be related to internal volume as it’s worse with the output up and can be triggered by raising the cab volume after the amp block. Also, it only seems to happen when using the main outputs (level all the way up), not using headphones (level around 25%). Didn’t notice this on the axe 3 or any other devices.

Any ideas?
 

yeky83

Power User
I'm getting some feedback with high gain, especially when using some kind of boost. I’ve swapped guitars, changed firmware, changed amp models, and its persistent. It may be related to internal volume as it’s worse with the output up and can be triggered by raising the cab volume after the amp block. Also, it only seems to happen when using the main outputs (level all the way up), not using headphones (level around 25%). Didn’t notice this on the axe 3 or any other devices.

Any ideas?
Interesting, what kind of feedback? I assume it’s somehow different from a natural guitar-speaker feedback, how so?
Using external pedal boost or internal boost?
 

markyd

Inspired
This is what I posted in the firmware thread:
I just noticed this with super high gain amps. I am running output 2 into a power amp and guitar cabinet, and and output one with a cab sim into my studio monitors. I get horrible squealing when output one knob is turned up anywhere past noon. I unplugged output one and the problem was still there on output 2 until I turned output 1 down even when there was nothing connected to output 1.
Try connecting output 2 only and turn down output one. The problem should go away. This seems like a big bug to me.
 

Jarick

Experienced
This is what I posted in the firmware thread:

I can verify if I turn down the Output 1 level the squealing goes away. It's almost like the output is microphonic?

I hooked up Output 2 and changed the output block and there's no squealing issues. Not sure if the output level is the same but it's in the ballpark.

If I change Output 2 to copy Output 1, the volume is incredibly high.
 

chris

Legend!
I'm getting some feedback with high gain, especially when using some kind of boost. I’ve swapped guitars, changed firmware, changed amp models, and its persistent. It may be related to internal volume as it’s worse with the output up and can be triggered by raising the cab volume after the amp block. Also, it only seems to happen when using the main outputs (level all the way up), not using headphones (level around 25%). Didn’t notice this on the axe 3 or any other devices.

Any ideas?
Angle Severe High with Drive at 10, Master volume raised and Drive boost on?
 

markyd

Inspired
Not judging. I think that’s the detail he mentioned in the other thread. I’m asking. That much gain could be pertinent to the conversation.
Of course a lot of gain can result in feedback, but the fact that turning down output one will stop the squealing with no change in the tone points to an internal issue.
 

chris

Legend!
Of course a lot of gain can result in feedback, but the fact that turning down output one will stop the squealing with no change in the tone points to an internal issue.
turning down the output on a real amp also stops squealing i think. gain is gain, whether digital or analog. i think that may just be too much gain.

does this only happen in a recent firmware and not before that?
 

markyd

Inspired
turning down the output on a real amp also stops squealing i think. gain is gain, whether digital or analog. i think that may just be too much gain.

does this only happen in a recent firmware and not before that?
My point is that with NOTHING CONNECTED to output one if you turn down output one the squealing will stop. The gain on output 2 will remain the same.
 

Jarick

Experienced
Yes and I had an Axe 3 and never had an issue and two AX8’s and never had an issue. Like I said this is a factory preset so nothing that shouldn’t be dialed in. And only happening on one output.
 

markyd

Inspired
Here is a preset to test. Hook up output 2 only. Turn up the output one knob on the unit. you will hear feedback/squealing. Turn down output 1 or bypass the output one block. the feedback/squealing will stop.
Thanks for helping!
 

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yeky83

Power User
Can you try using Input2 instead of Input1 for guitar input, see if that improves it?

Or use Input1 but route Out1 signal only to Out1-right, muting Out1-left. Less squeal?
 
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Randalljax

Fractal Fanatic
Had to dig back as there was similar issue in 1.03 beta 5 it a long shot but try this maybe it was from Cliff

The problem is the Input 1 Right data is corrupted. I found a workaround:
Put a Volume block immediately after the Input 1 block. Set the Input Select to Left Only.
 

yek

Moderator
Moderator
Output 1 and output 2 can have different output levels. Check Setup > I/O > Audio.

I am running output 2 into a power amp and guitar cabinet

If so, you shouldn't connect Output 2 to the Cab block, like you have done in the attached preset.
 

chris

Legend!
Here is a preset to test. Hook up output 2 only. Turn up the output one knob on the unit. you will hear feedback/squealing. Turn down output 1 or bypass the output one block. the feedback/squealing will stop.
Thanks for helping!
i loaded the preset and saved.

i disconnected XLR from Out 1.

i connected 2x 1/4" cables from Out 2 to my mixer 1/4" input.

i have both Out 1 and Out 2 knobs down.

i have a guitar plugged in to Input 1.

i turn up Out 2 all the way - i have a high gain guitar sound.

i mute my guitar strings.

i turn up Out 1 all the way - no change in sound, no squeal or any noise at all. Playing guitar has the same sound as before, no squealing.

is that the right reproduction procedure?

also, Out 1's level on the VU meters in the Layout>Zoom Out view is much louder than Out 2, and Out 1 is clipping when using this preset if Out 2 I/O Menu "Boost/Pad" is set to 0. if i change Out 2 Boost/Pad to 18dB, the level is just about at the Level Set line. the CPU of this preset is also pretty high, in the 85% range, and this can lead to CPU and slowness issues.

other than Out 1 clipping and high CPU, i don't see an issue with this preset, and don't hear any squealing.

i agree with Yek, that if you are using a power amp and real cab with Out 2, you generally don't send a Cab block through Out 2 to a real cab.
 
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