I have an ampeg v4b cl all tube bass amp head and the tubes are malfunctioning. I turn on the amp to let the tubes start warming up but nothing happens. I just got the amp serviced and had the fuses and tubes replaced because the same thing happened about a month ago. Could I have blown a fuse or something like that? If so what are some common things that would cause that to happen?
If you are getting nothing from a tube amp, a blown fuse is the first suspect. You should always keep a couple of them on hand to see if you've got a blown fuse.

If your amp is blowing fuses regularly, take it to a technician. You definitely have a problem.

If the indicator light comes on and stays on, then it is not likely to be a blown fuse. it could be a great many things; some simple and some not so simple.
"Maybe this world is another planet's hell?" - Aldous Huxley
A. Is it plugged in. [Seems rude but was the 1st question when I did computer tech support in the late 80's].

B. It it turned on? [If it turns on, and you see that there is power to the indicator Light, it is not the fuse, nor is it the power supply.]

C. Does any amount of signal from the bass make it through the amp to the speaker when plugged in and even when turned all the way up?

D. If your amp has an effects loop, turn the master volume all the way down, plug a cord in the return, touch the end of the cord while slowly turning up the volume. If you get nothing, it is your power section that needs service. If you hear something, it is the preamp section that needs service.

Blowing a fuse comes from running the amp very hard. I have not blown a fuse since having over 120 watts.

Blowing a fuse can also mean a short inside the chassis.

Ampeg bass amps have and will slowly disintegrate from vibration exposure from being placed upon the cabinet during live performances and rehearsals. It is an eventuality for all bass amps.

Keep all tube amps off of and away from bass cabinets.
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