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SWR SM900 Tube Noise

Discussion in 'Amps and Cabs [BG]' started by DRN, Jul 17, 2003.

  1. Jul 17, 2003 #1
    DRN

    DRN

    Mar 17, 2002
    Las Vegas
    I thought I would do some experimenting with tubes. So I went to the tubestore.com and ordered three different tubes to try. I put the highly recommended Electroharmonix tube in and the entire amp hummed really loud. The tube had a great sound but the amp hummed. So I changed to the next tube JJ and the same thing happens but not as bad as the first. I am going to put the third in Friday.

    Have any of you run into this? Am I doing something wrong?

    Please help

    :confused:
     
  2. Mar 24, 2009 #2
    scottsnellgrove

    scottsnellgrove

    Nov 20, 2006
    Northeast Arkansas
    How do you get the tube out in the first place.
     
  3. Mar 24, 2009 #3
    BassmanPaul

    BassmanPaul Inactive

    Aug 25, 2007
    Scarborough Ontario Canada
    Could be that the heater supply has a circuit to balance out hum. If so it might need to be reset for each new tube for best results. I am assuming you replaced the tube with one of the exact same type?

    Paul