Advice: SVT II (non-pro) Power tubes..which is what?

Discussion in 'Amps and Cabs [BG]' started by wzrdofgz, Sep 23, 2005.

  1. Just picked up a used SVT II (non-pro)..sounds great. However, I noticed that the first tube, (when looking face on L/R the 1st one on the Left) is not glowing. Is it shot? I've got a schematic but can't tell what the order of tubes are & how they function. Please advise ASAP!!! :meh: :crying:
  2. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    Chances are that if you can turn it up and sound good, the tube is OK. If you get distortion or the sound cuts or something, you need to get it replaced.
  3. Then leave it at that. An amp with bad tubes sounds...bad!

    The "glow" is the heater filament and it's not always visible. It doesn't matter if you can see it or not, if the tube weren't working, you could hear it.


    Leave it alone. If you think you have a real problem, take the amp to a reputable repair technician.
  4. okabass


    Mar 19, 2005
    It is sometimes hard to see the filament glow; the filament is so deep in the cathodetube or the tube's construction makes it impossible.
    You have to check the tube in complete darkness. There should be at least a faint glow. If there's no glow, the tube filament has broken, and the tube does not work.
    In my oppinon it is very difficult to hear, that one tube of the powertube sextet has gone. Let Your repairman check the problem.
  5. Its probably fine, but get a tech to check it out anyway, i never did that when i first got mine, and it was fine for a while, but then started going boobies up, but they were old tubes (about 14 yr old tubes at least ), and it had been a workhorse amp, however, yeah, they are damned nice amps! ;)