Odd problem WT550

Discussion in 'Amps and Cabs [BG]' started by HoboCop, Dec 22, 2018.

  1. Hi all, I was wondering if any of you had ever seen anything like this problem. I have this WT550 that I've owned for about 15 years. I also have a number of Avatar cabs that I've owned longer. I was using the SB112 and the eden as a practice rig, and I noticed that the volume would fluctuate and drop off almost completely after about 15 minutes of playing time. It's a really reproducible problem, and it happens with all 3 of the cabs I have (all 8ohm, an SB112, and SB126, and an SB115). So I took it to a good tech in the area, figured it was the thermal circuit. He kept the amp for about 2 months and eventually just cleaned it up some and returned it. He could not reproduce the issue.

    So I get it home, and I can reproduce the problem just as before. So out of curiosity, I hook up 2 of the cabs instead of just 1. With 2 cabs at a 4ohm load I can't get it to fail. What's happening here?
  2. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    Volume drop issue is well known with this amp. No actual fix posted just usual wild guesses from effects loop, to bass battery, tube replacement, jack or pot cleaning, bad cords, bad line voltage.

    And none of them fix the problem. Most likely limiter circuit based on impedance/output levels and circuit is wonky gets hung up.

    Either there's a known fix by authorized Eden repair or nobody can fix it. They just replace the board

    Possible your tech tested it with a 4ohm load higher impedance like 8ohm or even 16ohm will probably get the circuit to respond and get hung up quicker
  3. AlexanderB


    Feb 25, 2007
    I do not know these amps, but for a given output POWER, lower impedance will reduce voltage swing but increase current draw. Running two cabs will then further reduce the demand for voltage swing for a given loudness, s the increased cabinet volume and cone area will increase sensitivity.