SWR SM900 Tube Noise

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

  1. 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

  2. How do you get the tube out in the first place.
  3. BassmanPaul

    BassmanPaul Inactive

    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?