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Why does my amp overdrive?

Discussion in 'Amps and Cabs [BG]' started by cgworkman, Apr 7, 2006.


  1. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    I'm playing a Lakland 55-02 --> BBE Bmax (SS) --> QSC RMX 2450 (bridged at 8 ohms) --> SWR Goliath III (8 ohm).

    I've noticed at times that no matter what I do I seem to get a overdriven signal from my setup. It might even be the faintest distortion at times, but it's still there. I've played around with the gain/master volume/amp level controls trying to eliminate this problem--but cannot shake it. It seems to really noticeable when I run the MM pup solo.

    I've tried lowering my pups--I've backed off the gain inside the control cavity on the Lakland--but nothing seems to help. It's not really a loudness issue since it will even do it at low to medium volumes.

    I call it overdrive (not distortion) because it's a nice, warm overdrive sound. Almost old-school tube like. I'd probably be really happy with it if I was going for an overdriven sound. But unfortunately I'm not ;)

    I've read reports of the overly sensitive input on the BBE. Could that be my problem? I'm going to try another preamp this weekend. Should I consider sending the preamp back to BBE and having them back it off a bit?

    Any suggestions on what to try next?
     
  2. WalterBush

    WalterBush

    Feb 27, 2005
    Yuma, Az
    Full disclosure, I'm a certified Fender technician working in a music store that carries Fender, Yamaha, and Ibanez products among others.
    The Bmas SS preamps have a bit of a headroom problem. Although it's been fixed in later production runs, plenty of units still overdrive easily--including mine!

    According to other folks on TB, BBE is happy to fix this problem for you, although I'm not sure whether or not they'll charge you, since I haven't had it done to mine yet. Were I in your shoes, I'd look at the Bmax as the most likely cause of your problem.
     
  3. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    It seems the buzzing/distortion is actually a soon-to-be-blown speaker in my SWR GIII.

    Anyone know where I can pick up a replacement?
     
  4. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    so apparently this is something recent and hasn't always
    been that way?

    Not up on SWR but high probability the speakers is an Eminence (67 speaker code) which is a good thing cause pretty much anyone can recone an Eminence - which is exactly what I'd do. Roughly $75. They can also give you a second opinion on it's condition but a bass in more likely to show an issue than a tone generator. Check around for reputable repair or you can ship it off if necessary but shouldn't be in Ohio.

    You can do a net search but (a new one would run you twice what reconing will - and reconed it will be new), probabilty is you'll have much better luck finding a guy to recone than finding a replacement. Do some checkup on the recone dude - or take it to someone you can get some reference on. Always helps to have contacts for gear repair - and they all know each other.
     
  5. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    It's actually a PAS driver--which is the problem. Obviously they seem to be hard to come by. I've contacted several SWR dealers here in Ohio and they've pretty much blown me off.

    :(
     
  6. bassjigga

    bassjigga

    Aug 6, 2003
    Why is it overdriving? Because the RMX 2450 puts 1300-1500 watts into an 8 ohm load. The SWR Goliath is designed to handle 750.
     
  7. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    Try searching here on TB. You'll find you don't know what you're talking about. Wattage has nothing to do with blowing speakers or overdriving a preamp.
     
  8. bassjigga

    bassjigga

    Aug 6, 2003
    Oh I beg to differ. I suspect the reason most people are able to get away with extra wattage into speakers is because most amp companies exaggerate their power ratings.
     
  9. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    It's called 'headroom.' I've been using high powered amps for decades.

    The GIII will run at 700 watts. It's peak power is 1400 watts. There's your rating. The QSC doesn't run at 1400 watts all the time. It's called headroom.

    I bought a used GIII cab that I've found has a defective driver. I'm seeking info on getting that replaced since I can't get a local delaer to do anything. I've been running my other GIII for years with this same setup.

    EDIT: Do a search for this subject here on TB. There are several knowledgable members (many of them actually work for amp companies) that will tell you what I'm saying is correct. If that doesn't work click here.
     
  10. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
     

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