MT15 Driving me nuts

[elvis]

An oscillation for sure. Could be a lot of causes. The guitar is part of it, since shorting the input (guitar volume down) stops it.

I assume you’ve tried a different cable, but if not, that’s one thing to rule out.

What happens if you put a buffered pedal in front of the amp?

 

[Tone-y]

Watching your video, and also what you'd already said about changing guitars, standing in a different room, using low gain etc, that definitely isn't a pickup/guitar problem.

You've changed all the valves now to eliminate them haven't you? I honestly don't know what else it could be apart from a wiring issue. Looks like a call to PRS customer support is in order

 

[elvis]

Given that the oscillation starts when the guitar volume is turned up and stops again when the volume is turned back down, I'd suggest that it's not a middle of back stage instability. If it were, it wouldn't stop once started.

Seems like an interaction between the front stage and guitar/cable impedance.

Could be wiring. Could be the long cable. If you can decouple the guitar from the amp by a buffered pedal, it would be useful to know if it still oscillated.

 

[bodia]

An oscillation for sure. Could be a lot of causes. The guitar is part of it, since shorting the input (guitar volume down) stops it.

I assume you’ve tried a different cable, but if not, that’s one thing to rule out.

What happens if you put a buffered pedal in front of the amp?

Good call on the cable. I had a bad patch cable on my pedal board that did the exact same thing on my MT-15. It was rather odd because it was not noticeable on the clean channel. Once I went Red...........look out!

 

[Wakester]

Sounds like high end feedback to me. Does it happen on the low power setting?

 

[Rooster7six]

Sorry have been crazy busy. I've done everything I could think of until today. I have an aby switch and tried it with the ground lift. No more noise! WTH.

 

[Rooster7six]

Sounds like high end feedback to me. Does it happen on the low power setting?

I didn't try that. I'm not a big fan of the sound in low power mode but tomorrow I'll try that just to see

 

[X-Mann]

Sorry have been crazy busy. I've done everything I could think of until today. I have an aby switch and tried it with the ground lift. No more noise! WTH.

I had a ground loop buzz in my all
Metal chassis Carvin Legacy-3 that was only removed by a Ebtech HumX.

I use one on the power cord of all my amps & use it on my MT15.

I’m still loving this amp!!!

X

 

[Rooster7six]

I had a ground loop buzz in my all
Metal chassis Carvin Legacy-3 that was only removed by a Ebtech HumX.

I use one on the power cord of all my amps & use it on my MT15.

I’m still loving this amp!!!

X

Haha I'll have to Google that!