Guitar Gear Forum

Amp. Old Tube Runner MVT 1000 FT in like new shape. 60w, (can't find a schematic for it) Pre-amp Tube GE 12 ax7 short/black

Symptom: While playing, suddenly no sound..a very quiet dead. Like the amps not even plugged in.... not even the very slight tube hiss/buzz.. no prior sounds as a pop etc.

Frequency: very seldom and usually within the first 20-30 min of playing.

To note: All reference indicator lights on, on/off amp. and tube lit... Have a front and effects pedal ( 2 ea.). Indicator lights on, including power block light.

Took out the White Finger compressor from the front as it is a separate voltage. Same thing happened again.

Attempt note: It does not cut back on after going off. Cutting off pedals and turning back on has no effect. Turn amp off then on and it works fine. Only odd notation: It seems the 'reverb' or contour is not as active when this happens when first turned on. When you turn the amp on/off and wait longer, there is a noticeable 'sound' depth difference..

ANY IDEA'S or suggestions welcome...as to what to replace etc. anyone with a schematic would be nice as well.

Thank you for your time.

Welcome to the fold brother!

There are a few technical wizards here that will be able to help more than I, but off the top of my head...

First thought: Most amp don't have one but, maybe you have an internal, thermal cut off switch that's malfunctioning?
Second thought: bad speaker connection.
Third thought: call the manufacturer

Good luck bro!!!

google turns up a tuberider mvt 1000ft. if that's what you have, it's a solid state amp.

the most likely issue is that it's being shut down due to a protection device. that could be because the device is bad, or because the mosfets are failing or overheating. i have seen SS power amps get hot enough to melt the solder on some leads, causing similar symptoms, but the fact that you can turn the amp off then immediately back on and get sound tells me that it's likely a protection device causing the problem.

there's really nothing in there that's user serviceable, so taking it to a tech that's good with SS amps is the only real solution IMO.