Fixing a small combo amp

Discussion in 'Amps and Cabs [BG]' started by jdieh1, Jan 9, 2009.

  1. jdieh1

    jdieh1 Guest

    Nov 28, 2007
    Queensland, Australia
    I've got this annoying buzz inside my small practice combo amp. It's a Kustom (ugh, I know), 10 watt.

    So I was thinking that maybe I could just open it up, tighten a few screws etc until I find the problem, but is it really that easy?

    Should I take any precautions while opening it so I don't get electrocuted or anything? Obviously I have to take it out of the power, anything else? It has a warning sign on the back that says not to open it in case of getting shocked...

    Any suggestions?
  2. T-Bird

    T-Bird Guest


    Is the combo under warranty?

    If it is, You'll void the warranty by opening the amp.

    SS amps, especially the low powered ones, are quite forgiving when it comes down to shocking people. Even if the caps are fully loaded, You'll only feel a snip. You do have to remember to unplug the amp first though. Waiting for a 10 minutes or so before opening 'er up should bleed the caps.

    Rattles/buzzes usually come from the amp/cab joints, sometimes just tightening or loosening the amp section screws does the trick.

    If the sound comes from an air leak, cheap combos are notorious for not having the speaker wire hole sealed, so sometimes it whistles rather badly. If You seal it, You probably have to lenghten the wires because otherwise You won't be able to remove either the amp or the speaker depending of where the slack is.

    Air leaks around the speaker is also quite common. While the speaker is off, make sure that the connecting leads from the binding posts to the cone don't rub against the cone. And when re-installing the speaker, use a some kind of sealing material between the cab and the speaker.

    Projects like that are quite rewarding actually because if You don't break anything accidentally, like a screwdriver through the cone or the surround, theres a really slim chance of making things worse ;).

  3. BillyIVbass


    Sep 24, 2008
    Gear Reviews Guitar World Online
    +1 on trying to diagnose if it's a construction sound rattle vs. an electrical buzz. Personally I'd be afraid to mess too much with the electronics, but that's your call.
  4. jdieh1

    jdieh1 Guest

    Nov 28, 2007
    Queensland, Australia
    No it has run out of warranty, I was too stupid to get it looked at while it was still under warranty.

    Thanks for your help. I'll have a crack at it now :)
  5. hbarcat

    hbarcat Supporting Member

    Aug 24, 2006
    Rochelle, Illinois
    Cheap combo amps are notorious for developing loose joints and components. I've fixed these before by opening up the amp and spooging some silicon sealer around wherever things look like they might be loose (which is everywhere). I've even taken scraps of wood and glued and screwed them in place to act as additional bracing and to tighten up anything that might be prone to vibrate.
  6. jdieh1

    jdieh1 Guest

    Nov 28, 2007
    Queensland, Australia
    It turns out that it was a little bracket inside the head? part of the combo that wasn't screwed in tight enough. I've tightened it up and it doesn't rattle any more :)

    Yay for me
  7. Yep - screw it all togteher again with brass screws and brass cups (it'll look a bit like a Marshall vintage amp after this). Check the jack cable you are using - anthing costing less than $10 isn't much good and the really cheap ones have all sorts of bangs and clicks in them when they get moved about. Are you sure it's not your bass causing the problem (screening, shorts, loose socket?)
  8. jdieh1

    jdieh1 Guest

    Nov 28, 2007
    Queensland, Australia
    Yeah, I'm sure. I've played my bass on multiple amps before and it plays fine on them. It's a dodgy amp. I fixed the major problem though