xXBansheeXx

Yeah, it's always been in the loop. I have it assigned to only be in the clean channel and I don't notice the phasing as much in the clean channel. But this is not phasing at all, it's a constant like 1000khz squeal that sounds like it has a circular motion to it. EDIT: Another thing to add, if I turn the amp on and don't play anything yet, the sound isn't there, but if I make any noise at all with the guitar, the warbling sound slowly starts to fade in until it's full blast much like feedback from a PA system would. You know how it starts faint and then quickly builds on itself exponentially until it's a full blown squeal? It's just like that except it sounds like it's going through a rotary speaker. And this is with no effects on whatsoever. So it's very reminiscent of a feedback issue. I have yet to try the M13 on another amp because I have it rack mounted on a drawer in my flight case and it's not easy to get to. But I'm almost positive it's the M13 with the issue.

I'm aware of the phasing issues with the effects loop, but I've been using this pedal for years without the described issue. This issue is new and has nothing to do with the effects loop. It seems to be some kind of feedback issue. I'll try the reset when I get off work.

The amp is a Mesa Dual Rectifier, some tubes blew and burned some resistors. I have the M13 in the effects loop on, so the amps send goes into the M13 input and the M13 output goes into the amps return. I wouldn't know how to reset the M13 and I don't have any midi cables or anything to re-install the firmware. I haven't tried any other effects in the loop of the amp, but the fact that I switched the M13 to true bypass and the problem went away tells me that it has nothing to do with my amp.

So I had some amp issues and I sent my amp out to be repaired while I left my M13 being unused for about a month. When I got my amp back, I put it back into the rig and now I have this relatively higher pitched warbling noise. It almost sounds like a squeaky ceiling fan, it's about that speed and pitch if you can imagine it. All the effects and everything still work, when I turn them on, the warbling noise takes on the effect, so it's somewhere in the beginning of the signal path in the M13. Before you ask, yes I have trouble shot everything in my rig, every pedal, every cable, whatever this is, it's inside the M13. If I go into the setup menu and switch the M13 to true bypass, the warbling goes away. Then as soon as I kick an effect in, the effect comes in with the warble in it. So something happened to my M13 over the past month to cause this swirling/warbling sound. Has anyone else experienced this or have any idea of where to start looking? Thanks