MT15 (temporary?) volume drop?


New Member
Nov 28, 2020
Hi everyone,

A few days ago I had an issue with my MT15 as the volume dropped significantly (by 80-90%) on both channels.

I've bought it new 11 months ago and almost the entire time it sat at my bandmate's house where we have rehearsals. I have a few pedals in the fx loop, have the amp connected into a 212 v30 cab, no issues.

A few days ago I moved it for the first time - I have a gig next Saturday as a stand in for a local band, so we met to go through the songs. I reconnected everything at their drummer's house (I did notice the amp picking up some interference right off the bat) and we played for about 1-1.5 hours. Then suddenly, the volume dropped. I unplugged everything and just ran my guitar directly into the amp - no pedals or anything. Volume was still missing. All the controls worked, only it was very quiet.

I took my amp home and two days later went to my bandmate's house. Tried playing it through his cab and everything worked perfectly. Today I played it at home through my cab again, and again it works without an issue.

I didn't manage to run it for more than half an hour, will try that later.

I am wondering what this could be? I was hoping it was one of the tubes, but the fact it plays normally again has me baffled. I am not too handy when it comes to electronis, so I cannot test everything and even though it should still be under warranty, with the gig comming up, I don't really have time to take it to the dealer.

Could this have been a one off in any way? The electricity in the guy's house where my amp had an issue seemed really dodgy. I don't think he has any grounding in his power outlets and the entire room was "electrified" with a bunch of extension cords.
What can I even do in this situation? Wait until the problem repeats and/or gets worse and take it to service? This was on half power setting, but afterwards it worked normally on both half and full power.
If it only happened at one location, I would be suspicious about the conditions there. I actually had this happen at my house with 3 brand new amps. Bought one, brought it home, played for awhile and volume dropped. Since it was brand new, I took it back and exchanged it. Same thing happened. Repeat again with same outcome. Finally figured out it must be my power. Bought a power conditioner and never looked back.
Ugh....I'm dealing with this right now on a totally different amp. Diezel D-Moll. The amp is loud and proud but when I switch to clean the volume drops like 90%....I crank up the channel vol and gain and you hear crackles...and it gets full power...then I back off it's normal. Dirt channels are normal....but I could tell they are affected some. Brand new amp as well. I've started replacing/swapping preamp trouble shooting has started....I'm in process.

All my tubes looked normal....lit up normal...but I know that doesn't mean they are actually 100%.

Just thought I'd share because if the problem persists with MT15 maybe it has a bad preamp tube...that isn't completely dead.