Strange Smell and Weird Things possibly coming from my cab/head

Discussion in 'Amps and Cabs [BG]' started by Ogbassist, Jan 1, 2013.

  1. Ogbassist


    Feb 16, 2012
    Hey guys, I have been practicing with my band and we've noticed a strange smell and we think its coming from my gear. It kinda smells like electrical burning but im not too positive. I have the PF-500 head by ampeg and the 4x10 hlf cab. The head is rated 500w rms and the cab is rated 400rms it only happens when i turn it past half'ish way. dunno what it is or whats causing it. any ideas? also....every now and then when its past half way i sometimes lose power for a half second or so.
  2. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    There's no way to tell where HALFWAY is by knob positions. Too many other variables. Some amps can output FULL power when the volume knob;s at noon. But, a burning smell is bad news. If the amp is new, take it back. Otherwise, I'd be looking for an amp tech. But, don't assume you're only at half power, or that your cab can handle it anyway.
  3. First every and anyone needs to understand that almost all amp "volume" knobs are not like a gas pedal. By 12:00 to 2:00 are at there MAX clean rated power, some by 11:30.
    At 12:00 or better with a 410 you should be at levels dangerous and damaging to your hearing unless you have already blown speakers in the cab.
    The cutting out and burning smell is most likely from the cab but cutting out IIRC was an issue with the PF500. You need more speakers to get louder without driving the amp out of clean power (and ear plugs).
  4. Ogbassist


    Feb 16, 2012
    they are both around a year old
  5. Ogbassist


    Feb 16, 2012
    bass knob is set to 11
    mid range is set to about 4
    high is set to about 2:30
    gain is about noon
    master is around 7 when we are jamming hard
  6. Ogbassist


    Feb 16, 2012
    we have a lot of **** plugged up to the same outlet, could that be a possible factor? 200w guitar amp 200w pa system a piano and a bunch of eletronics
  7. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    A 200W GUITAR AMP!!! Oh gawd your poor ears!

    What cab is your guitar player putting his 200W into???

    In my mind you are trying to get more out of your cabinet than it has to give and thus the smell. Cabinet power ratings are usually the thermal limits of the driver(s). That's the point where they start to melt. In real world terms, a driver runs out of excursion at about half of its thermal power. After that point adding more power just ends up as heat and not sound. Driver failure at this point is imminent.

    The amp cutting out could well be the amp's protection circuit trying to save itself.
  8. R Baer

    R Baer Commercial User

    Jun 5, 2008
    President, Baer Amplification
    In my experience, I have never know a burning electrical smell coming from my gear to be a good thing. Contact Ampeg and have your amp serviced immediately.
  9. Guitar players are always power hungry. Just get everyone to turn down an equal amount. This can save your gear in the long run! Not to mention save your ears.
  10. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The cutting out sounds like the response to clipping. Some amps, typically class-D will do that, if they are not designed to tolerate clipping. It can also be protection circuits..... Overheating is usually a longer "outage", 15 sec for a heatsink overtemp, and 30 min if a transformer gets too hot.

    I dunno what technology is in that head, I didn't look it up.

    As for the smell......

    There is smell, and there is smell..... When a newish amp gets warm, there is often a smell of hot varnish as the last of the solvent is cooked out. That isn't a problem.

    A real burnt smell has a bit of that sharp smell of a match to it.....

    You probably will not get far with warranty service unless the thing actually fails in some way, or the tech finds charred stuff inside.