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When to change tubes? on a preamp.

Discussion in 'Amps and Cabs [BG]' started by Mcrelly, Oct 22, 2005.


  1. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    I'm pretty sure I'll be buying an 11 year old Eden WT-300. The trick is it has the ORIGINAL eden tube in it, but the amp seems like it was not used very much. maybe used for a handful of hours or two.

    can tube go bad (change tone) with JUST chronological age, not necessarily long usage time???
     
  2. popinfresh

    popinfresh

    Dec 23, 2004
    Melbourne, Aus
    Well preamp tubes last a LONG time. Then again, it's not like 1 preamp tube will break the bank.
    When you get it, if the tubes fine, then leave it. If it's not, replace it.
     
  3. Pickebass

    Pickebass Supporting Member

    Jul 12, 2004
    San Antonio, TX
    When I buy an amp that is not new, I change tubes to make sure I have the tone it's supposed to have. A couple of tubes will probably cost you around $25 total. If I notice there is no change, I either put back the originals, or just save them ofr other uses (all depends on how hard it is to change)
     
  4. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    The strange thing is when I play notes there is a quieter "buzz-saw" type sound ender neath each note? is that an indicator of bad tube?? my local shop said maybe microphic tube or bad capacitor. he told me to knock on the amp case with the volume on, if it buzzes then it's probably microphonics.

    ALSO: for about 4 seconds after flipping the power switch on I hear a moderate hum coming from the speakers, when the guitar sound starts coming through the hum goes away. IS THAT NORMAL?
     
  5. There are so many possibly causes for the buzz and hum, it's impossible to diagnose sight unseen. Preamp tubes are generally good for 50-100,000 hours. If you break that down by usage time, that pretty much mean 'indefinite life,' but modern preamp tubes vary widely in quality and not all of them will last that long. The amp you're getting is old enough that it could probably use a good going-through just to check things out.
     
  6. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    well, I answered my own question. I have the portable Korg ca-30 tuner plugged into the "tuner out" and when the tuner is turned on I get the buzz-saw sound. I switched to the "effects send" and it didn't cause the same problem????, so now I will use the send.
     
  7. FunkyLemz

    FunkyLemz

    Oct 17, 2005
    Los Angeles, CA
    Im getting a tube pre off of ebay soon. Is it pretty easy to actually change the tube? Like pop off the top and unscrew.
    Mike