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whats goingon with my amp??

Discussion in 'Amps and Cabs [BG]' started by BassGreaser, Dec 28, 2002.


  1. BassGreaser

    BassGreaser

    Aug 22, 2002
    Austin, TX
    I'm starting to get at my rack. I have an Alembic F1 preamp running to a Steward PA-1000, which is bridged to two EA CxL-110's (both 8ohms). I have both cabs chained together by a speakon cable, then from the power amp, bridged to one cab. My problem is My power amp keeps shutting off. It's 1000watts to 4ohms. I've tried using a different power amp and is did the samething. What am I doing wrong! I really need help.
     
  2. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    I'd be looking at my speaker cable for a possible short as a starting point.
     
  3. BassGreaser

    BassGreaser

    Aug 22, 2002
    Austin, TX
    both cables are in perfect condition....
     
  4. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    Based on the fact that your amp, and another amp, both react the same way to the load, it would seem to be a problem with either:

    1. cables
    or
    2. cabinets

    Generally, (making lots of assumptions here) I would imagine your amp is shutting down because the load it sees is too low for it to drive. Perhaps the amp is in bridge mode and only wants to see an 8 ohm load; perhaps a cabinet is wired wrong so it's actually 4 ohms, or perhaps a cable has a short so that it is lower impedance itself.

    Just because a cable looks physically fine doesn't mean it's been wired up correctly or that it doesn't have some internal failure. I suggest that as an easy one to explore because it's the simplest to test.

    You can get a voltmeter from Radio Shack for about $20 which will tell you a little about your load (although it will only tell you about very simple problems, like a shorted cable).

    You could try pushing a single cab on each tap of your cable and see if the amp has the same problem; try both cabs individually on both cable ends and see if you can make it fail that way, and you will eliminate some variables.

    Basically, you know you can make it fail with 2 cabs on one cable. If you can make it fail in another configuration you will be able to determine what is the common element in the failure pattern.
     
  5. BassGreaser

    BassGreaser

    Aug 22, 2002
    Austin, TX
    Thanks!
    I'll try all those out. I'm almost readt to use sell the rack, and get an Ampeg SVT-CL, due to this stupid problem.:p
     
  6. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    My money's still on the cable; it's a $20 part as opposed to much more expensive components; it also takes a lot of physical stress.

    A local music store fried 2 heads by loaning them out for a customer with a bad cable. They only diagnosed it after loaning him an Ampeg SVT-400t which went into thermal shutdown instead of frying. It would run 5 minutes into a dead short (while one of his cabs worked on the other channel) and then cool off and come back for more. All night long for a 4 hour show. That sold me on buying an Ampeg SVT-400t and I played it happily for several years.