humming sm-400

Discussion in 'Amps and Cabs [BG]' started by alex011085, Sep 18, 2002.

  1. alex011085


    May 19, 2002
    I turned on my amp the other day and it started to hum, it has never done this until now. I checked the ground plug, tried a different outlet, check speaker connections, tried a different bass, then pulled off the cover and tunred it on again with the top cover off and the humming was coming form the large box shaped peice in the back right corner (if facing the head from the front). I htink it is called the power supply? I had it in the shop about a month ago and the tech replaced a power amp, cleaned all contacts (i.e. knobs) and ground connections. Do you think my power supply is going out or could it be when the tech cleaned the gruound connections one wasn't reatached properly? HELP PLEASE!!!!

    thank you
  2. Chuck M

    Chuck M Supporting Member

    May 2, 2000
    San Antonio, Texas
    If you are talking about a hum coming from the amp (not through the speakers) it sounds like you may have some loose plates in the transformer. It really will not cause any trouble other than being kind of anoying.