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Need Advice on Amp Fault

Discussion in 'Amps and Cabs [BG]' started by Daniel Domrow, Oct 24, 2009.

  1. I have warwick quad vi 600watt head which has a valve preamp inbuilt, the last couple of times I have practised with it has lost all sound I have thus turned of the power and let it sit for a while (maybe 15/20 minutes) thinking it maybe overheating issues and when switch back on it was working again. But last night after turning it on for about 5 mins it lost sound never to return tried it today, not happening. I noticed the valves are not glowing now when the power is on. Could it just be the valves? or maybe a fuse? or something much worse? I've only had the rig a short time and don't know to much about them. Any suggestions would be much appreciated.............:help::bawl:
  2. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    when it was working did they glow brightly and then dim when it faded out? sometimes its hard to see if they're glowing or not. the first thing i'd do is dim the lights in your house, turn the amp on and look at them.

    if there not lit at all, you might try replacing one valve at a time.
    if they're all the same tube, you only really need one to do it. if they start glowing, and you get sound great. if not, i'd look for a filament power problem in the either the power supply or the main filament supply trace, but without having your amp in front of me, i'm just guessing.

    if you're not familiar with working on amps, just take it to a tech. sounds like something pretty simple to me.
  3. sleepytime


    Nov 10, 2007
    Chicago, IL
    I'd check the fuse.
  4. would a fuse stop the valves from glowing? when it was working you could see them very easily now nothing. i plan to take it to a tech. but i would like some sort of idea. I've checked all leads, cab all fine it powers up just no glow or sound. Nothing at the headphone jack either.
  5. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    no glowing is either a bad tube or the the filament supply is suspect.
  6. are they costly to fix? so i can keep an i what i may get charged?
  7. username1


    Dec 28, 2005
    alberta canada
    Preamp tubes are usually only about $10 each. Is your pilot light coming on when you turn it on? If not you probably blew a fuse. I would have it checked out, if it turns out to be just a faulty tube it wont cost alot in labour and hopefully something else isnt wrong.
  8. Cool thanks i will take it in and hope for the best, thanks for your input guys.......:cool:
  9. Ok i have just replaced the 2 preamp valves and still nothing the amp powers up and the fuse looks fine but there is no signal. Might be a bit more detailed than i had hoped.:(:(:(

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