SWR SM900 Tube Noise

Discussion in 'Amps and Cabs [BG]' started by DRN, 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. How do you get the tube out in the first place.
     
  3. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto 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