AMPEG svt classic problem..help?

jaredcarman · #1 06-29-2010, 12:08 PM

ok so i had my classic retubed in january. there definitely should not be any huge problems with this thing yet. all the tubes light up fine. its just not giving me the thunder that is used to. it still plays but its not at full power. what could be going on here?

anderbass · #2 06-29-2010, 03:49 PM

If you play an active bass, try a new battery to rule that possibility out.

BassmanPaul · #3 06-29-2010, 03:58 PM

Check that each output tube has a blue glow when in operation. It should flicker as you play.

Paul

username1 · #4 06-29-2010, 05:33 PM

Were the driver tubes changed when amp was retubed? Its usualy a good idea to replace them when your output tubes are replaced as they work harder than the pre tubes.

JimmyM · #5 06-29-2010, 06:21 PM

another reason not to ever do a full retube. only replace the tube(s) that are bad and never do a full retube. besides wasting money, something like this can happen.

so did you have it biased by a tech when you replaced the power tubes or did you use the lights? on a retube, it must be biased by a tech first. they can set it much closer than you can with those lights. don't knwo if that's the problem, but it's the first thing i'd consider.

**B-string** · #6 06-29-2010, 06:31 PM

Quote:

Originally Posted by BassmanPaul

Check that each output tube has a blue glow when in operation. It should flicker as you play.

Paul

Quote:

Originally Posted by username1

Were the driver tubes changed when amp was retubed? Its usualy a good idea to replace them when your output tubes are replaced as they work harder than the pre tubes.

Quote:

Originally Posted by JimmyM

another reason not to ever do a full retube. only replace the tube(s) that are bad and never do a full retube. besides wasting money, something like this can happen.

so did you have it biased by a tech when you replaced the power tubes or did you use the lights? on a retube, it must be biased by a tech first. they can set it much closer than you can with those lights. don't knwo if that's the problem, but it's the first thing i'd consider.

Never be late to the party, all I have to add is new tubes doesn't mean they are as good as the ones they replaced. Brands vary from each other and new doesn't mean they are all good after a short while in service. There is a failure rate with new production.