"Skipp is a Music Man Amp Technician"


I've read some of the posts and will also comment. I'm an original Music
Man Repair Person from way back. If you ask Dan at Ernie Ball Service
about early MM Amplifier questions, he'll probably send you to me. I don't
charge a thing for helping people with questions over the internet.


** How unusual.....


: Unfortunately, this amp has the transistor drivers as shown in your
: last picture.

I wouldn't say unfortunate... the solid state cathode drive system is very
robust and clean. It takes a lot to kill the early Music Man Amplifiers
and even more to kill the solid state driver version.


** What asinine crap.

Those puny TO220 transistors in MM amp's cathodes *blow up* all the time.

When an output tube fails high current, it takes the driver device with it -
INSTANTLY.

This naturally kills the parallel tube too, in a 4 tube model.

No such thing is possible with the tube drive version.



The advantage of
the solid state system is the output tubes don't need to be rebias when
changing to a same type tube.


** Funny how MM provide a bias trim pot.


: MM amps have very high plate voltages at around 700V+.

Very high and nothing wrong with that. You just have to know to use high
quality tubes, which have been high pot tested for operation.


** Right - EVERY music store and tube dealer has them on offer.

LOL.


I don't like Sovtek Tubes in the Music Man
Amplifers, they tend to flash over at lower plate voltages. I always try
to find NOS Phillips, GE or Sylvania tubes... highpot test them before
placing them into the amplifier. No sense killing the repair cathode
drive circuit a second time.


** Is this dude into "double think" or WHAT !!!

The MM transistor drive scheme was a DISASTER.

Have a look at the Peavey Heritage VTX series.

PV got is right - by using TO3 devices for the job.




......... Phil