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Dumbass question about pre amp tubes

Discussion in 'Amps and Cabs [BG]' started by Fawkes007, Jan 29, 2006.

  1. Fawkes007


    Sep 13, 2005
    SF Bay Area
    OK, so I have an Ashdown ABM EVO 500. This is my first tube pre amp deal and I have had the amp since 2002. I have never replaced the pre amp tube. How do you know when it is time to do so?
  2. BbbyBld


    Oct 13, 2005
    Meridian, MS
    Either when the amp quits working right...or you get bored and you or someone else convinces you that a new tube will make the amp sound more creamy and buttery or something :D .
  3. Aguilar/Dave B.

    Aguilar/Dave B. Aguilar Amplification Commercial User

    Nov 8, 2003
    New York City
    President: Aguilar Amplification

    A preamp tube can last for a long, long time. Certainly as long as the other components in the preamp. I have amps from the sixties with the original tubes in them. Unless it becomes microphonic, just leave it in. Microphony will be intermittent crackling that will not be related to playing, but will just swell up and then die down. Most of the microphonic tubes I have experienced were that way from day 1.


    Dave B.
  4. Snakum


    Jan 25, 2006
    Greensboro, NC
    With guitar amps, I will change preamp and power tubes out if an amp is sounding noticeably 'tired', or will change only preamp tubes for a specific sound, less gain, more gain, etc.

    However, as someone else said, I have owned 20+ year old Peavey combos with the original tubes in them, still going strong. :)
  5. Retubing a preamp isn't that costly. Average $10-12 each. Rightly said, I was told the deterioration is slow enough not to be noticed - until you retube, then you hear the difference.

    With your rig on, tap on the tube with the eraser end of a pencil. If you get any sound out of the speakers, the tube is microphonic.