MT15 no output / sound!


New Member
May 11, 2019

So this MT15 fully powers on, all tubes lit, bias voltage readings are good. The cables have been checked, when switching the half power switch you can hear it in the speaker, the connection is active. I have tried multiple good sets of power tubes, no dice. I have swapped preamp tubes in and out, and literally no sound. I am waiting on a full tube set but I don't think it will remedy this. No sound from the speaker whatsoever save the power selector.

It does have an after-market output transformer (Mercury Magnetics), however, there is signal to the speaker.

It did start making a random pop sound here and there, at a volume above playing level and sometimes a kind of scratch sound...Additionally I have been running it attenuated with a Weber MiniMass, however the random sounds occurred with and without the attenuator in the setup. Solder joints all in tact,

Any Ideas?

Hard one... sounds like tubes or transformer to me, purely uneducated guess though. Have you tried running something into the effects loop to see if it will generate any sound from the amp that way? Could give you more info as to where the problem is.
I'll see if I can get anything out of the loop, worst case scenario I have the stock OT. Just a bummer if it is the case (New OT Sounds amazing, but only 2 years old), plus I'm wondering if my attenuator has anything to do with this, hopefully not. I'll wait for a full retube until surgery.

Serious amp tech shortage in Alaska. Last time I took my Triple Rec in it was in the shop for a whole year. Guy finally told me he was using the wrong schematic, wtf. Count the tubes bruh, lol.

I'll smoke some patience and run through it all again :)
Just a thought, because I experienced this on my Sonzera, could your fx loop leads be switched? I only have a delay pedal on mine, but I know if I have flip flopped the send and return cables, i get no guitar output. Then there is always remembering to actually plug the cable into the guitar too, but I'm sure you checked that already.
Unfortunately there is no sound with the power cable plugged in, cab hooked up and guitar plugged in only. I even tried bridging the loop for the hell of it. Whats weird is there is no sound at all coming from the speaker, like even cranked on Red with the gain all the way up, no hiss or anything. Dead quiet. The only time I can get sound out of the speaker its switching the half power toggle.

Thanks for the responses
Bummer! Wish I had a solution for you other than sending the amp in for repair.
I did a full retube and out the stock OT back in, still no dice. Input and speaker outs have continuity...At the end of my abilities here. The thing is fully lit, fuses intact... minus sound. I wonder what other component it could be?
That's the mod to get them crispy sounds ;)

Damn, hate to see that, it is a feat getting to the bottom of the pcb, the whole board must go out and that is a few hours of work. But better to have a resistor blown than a cap. What I found out on my MT15 that is making a whole lotta buzz, is that when I bridge the FX loop all buzz goes away and the signal is back to normal level, found out today. Now we both know where the problem is. Hope you repair it successfully and quickly.
Think it's because of the new transformer?
Possibly, but it may have acted in concert with the attenuator. The attenuator has variable impedance, so with an 8 ohm load on a 16 ohm output possibly. I didn't set up a mismatch obviously but who knows. Honestly attenuating this amp sounds worse than just running a pedal through the FX loop and using it as a master volume. I had a Mesa EQ I used to get bedroom levels, I was using the attenuator as line out into a cabsim/headphones.

The resistor did its job and the tubes are all good. Worst case the factory OT stays in, and if it fires up and keeps popping I'll find a real tech to take a look. Meantime I guess it's Laney time...
I have this exact same problem just started one day when I turned it on and no sound. I checked everything as you did. I do not have a burnt resister. I checked cables swapped tubes. Tried everything. A sizzle sound from the OT maybe when I crank the gain on lead channel, or clean channel cranked and I strum guitar I get that sizzle sound near OT or power tube closest to the OT. Fuses are all good. Tubes glow. Just no sound