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Change tube in Ashdown head?

Discussion in 'Amps and Cabs [BG]' started by jock, Nov 2, 2000.

  1. jock


    Jun 7, 2000
    Stockholm, Sweden
    Will it change the sound?
    Can it sound even better with a Mullard or an other expencive tube?
  2. Chuck M

    Chuck M Supporting Member

    May 2, 2000
    San Antonio, Texas
    Preamp tubes have a large effect on the tone produced. A friend recently brought his SWR SM-400 over because he did not like the tone he was getting after he purchased the amp. We tried various 12AX7's and 7025's and found an older RCA 7025 in my collection that really improved the tone of his SWR.

    I usually favor the Groove Tubes 7025 which is currently not being imported do to a UN empbargo. Oddly, that tube did not sound too good in my friend's SWR.

  3. jock


    Jun 7, 2000
    Stockholm, Sweden
    This is a really old thread.
    I just bought an Ashdown again and it feels like coming home. This time it´s an ABM500 EVO and I´d like to hear about your experience when changing tube in these wonderful heads.
    The tube in my head rattels when I shake it (out of the socket), like a broken lightbulb. But it does work for now.
    What should I get to replace it?
  4. jock


    Jun 7, 2000
    Stockholm, Sweden
  5. Kaivinkone


    Aug 7, 2008
    I'd like to know how can i get my hands on the preamp tube inside, in order to change it. I read from somewhere that the tube is located just behind the input meter, so do i have to screw the meter off, or open the whole rear/front panel?
  6. Hi

    To get at the preamp valve in these heads, you need to undo the four bolts on the top of the dead. These are under the black plastic covers on the top of the head. Once you've taken these out, you can slide the whole chassis out, and behind the VU meter is the valve.
  7. Kaivinkone


    Aug 7, 2008
    Thanks a lot for such a quick answer! :)
  8. No probelm.
  9. An ECC83, although it's *meant* to be the same as a 12AX7, often gives more gain and a mids-bump.

    A 12AY7 might give you more headroom as will a 5751.

    You really have to experiment.

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