Fender Bassman 300 Pro Problems

Jahsteve · #1 08-30-2010, 06:46 AM

I was going to help a friend out an buy his Fender Bassman 300 Pro... It keeps blowing tubes...I spoke to a guy at work who has some experience in the tube audio dept... who said

"This sounds like excessive plate voltage.
My guess would be that something went south in the power supply over-biasing the tubes which created the theatrics he describes - or - Maybe a coupling cap was under-rated and shorted or something funky."

Any idea if this is an expensive venture? is the amp dead?
should i help him out and buy it for a fix..
any help appreciated.

KramerBassFan · #2 08-30-2010, 09:59 AM

Hard to say with out seeing it.

bassboysam · #3 08-30-2010, 10:02 AM

When I got my 300 PRO I had the same problem. changed the fuses to Slow Blow fuses and never happened again. cost was less than $20. I would still have it checked by a tech though.

BassmanPaul · #4 08-30-2010, 10:25 AM

I'll second the tech recommendation. Tube amps are dangerous and should be opened only by folk with experience of them.

I doubt that excessive B+ voltage is your trouble. I think you have a bias problem.

Expense? Much much less than your life is worth!

Paul

RickenBoogie · #5 08-30-2010, 11:52 AM

+1 to that.

D.M.N. · #6 08-30-2010, 12:06 PM

Aren't they supposed to have Slo-Blows? Mine has them.

seidler · #7 08-30-2010, 09:03 PM

Mine blew a tube and fuse when it was 4 months old. Took it in for service. Bought 6 new tubes. 6 months later (never left my house, practice only) it blew again. Repkaved the bad tube and 2 fuses and traded it for a ,little mark II and a sans amp tech 21 di tube emulator. Enough was enough.

rodl2005 · #8 08-30-2010, 09:53 PM

Never had a prob with mine. It DID have SLO-BLO fuses in it tho

Jahsteve · #9 08-31-2010, 03:54 AM

Thanks for the input... I'm going to stay away. Could be just a change of fuse, but seems like it could be a pain in the ar$$ in the future...