New Fender Solid State Tone Master Twin & Deluxe Reverb

ICBM

jpfamps said:

I've had a few of these (and FM65s) in with faults where the mute circuit come on after the amp was on for a few minutes which I never got to the bottom of. I could stop the amp cutting out by applying freeze spray to one of the transistors, but changing the transistors in that circuit didn't cure the problem. 

The mute circuit works by turning off the current source feeding the input diff amp of the power amp rather than muting the signal.

In one amp in an effort to try to understand the circuit better I ended up changing all the active components in the diff amp and mute circuit to no avail.

In the end I simply disabled the mute circuit. The amps would hum for a few seconds on start up but worked fine and have not come back.

In my view an overly complicated inexpensive amp: the worst sort.

I'll PM you for details if I get one with that, I haven't seen one yet. I'd far rather have a little hum at startup than an amp that stops working.

I agree about complex inexpensive amps being the most trouble, but I would really say it's unnecessary complexity that's the root of it rather than cost, and that can apply at a lot of price points... especially when mixing valves and solid state. I've seen nasty problems like that with Blackstar, Hughes & Kettner and Peavey as well as Fender at least so far, and I don't think any of those are really that inexpensive - the Fender was actually one of the new Twins, which are a pretty expensive amp.