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Thread: New preamp tubes

  1. #1

    Default New preamp tubes

    Not too long ago I replaced the preamp tubes in my Classic combo. I got the spec'd tubes directly from VHT. Ever since I've had a little more hum than usual and it's present on all channels. Also, if you play a chord while all volumes are down you can hear it where as this was not an issue with the old tubes. Does this have to do with some of the gain has been restored with the fresh tubes or is one of the tubes bitched? I don't have a tester to check them but I'm not sure that that's the problem anyway because the amp sounds better than ever.The tubes probably dont have more than a few hours play time on them as I have left my band in search of something heavier (tired of playing COCK ROCK). Do they need time to break in. Previuos to owning this amp I would have only switched out a tube if it had blown so I obviously have no experience knowing wheather this is normal or not. The slight hum is the only real problem, I'm just curious as to why I can hear my guitar when all volumes are down.

    Any knowledge on the situation would be greatly appreciated. THANKS

  2. #2

    Default

    Quote Originally Posted by VHT-J-CAN
    Not too long ago I replaced the preamp tubes in my Classic combo. I got the spec'd tubes directly from VHT. Ever since I've had a little more hum than usual and it's present on all channels. Also, if you play a chord while all volumes are down you can hear it where as this was not an issue with the old tubes. Does this have to do with some of the gain has been restored with the fresh tubes or is one of the tubes bitched? I don't have a tester to check them but I'm not sure that that's the problem anyway because the amp sounds better than ever.The tubes probably dont have more than a few hours play time on them as I have left my band in search of something heavier (tired of playing COCK ROCK). Do they need time to break in. Previuos to owning this amp I would have only switched out a tube if it had blown so I obviously have no experience knowing wheather this is normal or not. The slight hum is the only real problem, I'm just curious as to why I can hear my guitar when all volumes are down.

    Any knowledge on the situation would be greatly appreciated. THANKS
    I'd try another PI-tube if I were you and if that doesn't solve the problem try swapping the tubes with your old ones one by one until you've found the culprit.

    Good luck.

    Giga.

  3. #3
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    Exclamation

    Did you call VHT to tell them about this problem?

  4. #4

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    I haven't yet. I thought they might be off for the Holidays. I'll try after the New year.

  5. #5
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    Question

    It could be v1 ,v5 or the power tubes going bad.When my svets went I could hear a continous hum no matter what channel I was on.

  6. #6

    Default

    I changed out all the preamp tubes one at a time and it turned out to be one of the new ruby's. There's no more hum but still a slight psssssss. I also have svets in the power section but I dont know how old they are because they were the ones it shipped with when I bought it. I have 2 full matched sets of Ruby's to put in it but I have to drive 250 miles to Toronto to have it biased. Kind of a pain in my ass!

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