using an amp with missing/blown tubes

Discussion in 'Amps and Cabs [BG]' started by Golem II, Jan 26, 2002.

  1. Golem II

    Golem II

    Jan 4, 2002
    Macon, GA, USA
    Is it possible to play through a tube amp like, say, a mesa boogie bass 400+ if it doesn't have its full complement of tubes? I read a user review somewhere in which someone claimed to have run the amp with just three or four tubes, though it obviously didn't sound too good. If just one or two power tubes are missing, will the amp run at lower wattage or place extra strain on the remaining tubes? My guess is that running it with a blown tube is less dangerous than running it with a tube that's not there at all. I just bought a bass 400+ used, and it's in need of retubing but I'd like to verify whether it works at all before I bother to retube it.
  2. Running a tube amp with a bad tube is like driving a car with a flat tire, it ain't a good thing to do and can lead to more costly damage and repairs. It is possible to run some tube amps with a pair missing but it has to be the right pair and it will reduce output power.
  3. Matthias


    May 30, 2000
    Vienna, Austria
    I'm anything else but a tube amp expert, but I've read that the old SVT's featured a circuitry which allowed to run the amp with a blown tube (with reduced power output of course)

  4. BassBrad is right. It may work in some cases, but it is not recommended.

    Will your car get you down the road with a flat tire? Yes. Will driving like that mess up your rim? Probably. Could you lose control of the car due to the flat, causing the car to crash into a tree, totalling the car? Of course.

    The analogy holds for the amp too. Running it with broken or missing parts is a no-no.