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View Full Version : Fender Studio Bass Amp Volume Question

voodoohound
08-18-2008, 07:31 AM
Since a week or two I own a 1979 Fender Studio Bass Amp in pretty good shape. This baby drives 6 6L6GC power tubes and is rated at 180Watt into one 15" Special designed EV speaker. I have bought a set of six matched TAD 6L6GC-STR power tubes and also new preamp tubes. All tubes are working good - I have tried them in other amps.
PROBLEM: When I power the amp up the maximum volume is way too low - 180 Watt should move a lot of air. Do you have experiences with this amp or any idea what the problem coud be? The tone is great and all the controls work fine. The amp has no bias level control but a a tube matching pot. The schematic says 500V on the plates. Even with the old original tubes the volume is too low at max.

Thank you very much for your help!! Best Regards, M.J.
RedMan
08-18-2008, 09:55 AM
These amps are powerful but they don't have a lot of gain and are voiced for bass. That may be why you think it's not very loud. Do you have a way to measure the output?
voodoohound
08-20-2008, 02:50 AM
Thank you very much for the post RedMan. I never measured the actual output - but I measured the plate voltage (538V) and the cathode current (-13mA). The bias voltage is -66Volt. If I am correct that is about 7Watt for one 6L6 ..pretty low I think.
But yes - maybe I am totally wrong and the volume is in a normal range for a bass amp. I am a guitar player and I bought the amp for our bass player. But I can play this amp with a bass in our house with both volumes on 10 and my wife does not pull the plug.
There is not much info about this amp in the web, but almost everybody says that it's a loud amp. Is there anything else I can check? Thank you very much!
RedMan
08-20-2008, 04:03 PM
Put your volt meter across the output set to AC volts when you're cranking it out and see what kind of voltage you get out of it.
voodoohound
08-22-2008, 09:41 AM
Oh yes - that's easy - thanks for the tip! I wanted to do this but after playing for five minutes the amp did blow the fuse. I will take the Studio bass amp to a tech. Once again - thank very much for the help! M.J.