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Power Amp Not Good For Bass?

Discussion in 'Amps and Cabs [BG]' started by rbbonfire, Sep 7, 2004.


  1. rbbonfire

    rbbonfire

    Jan 20, 2004
    I have just started looking at power amps. I have seen various descriptions that describe one particular amp as being good for PA, another for monitors, another for subs, another for bass, etc. I have always thought that a 1,000 watt power amp was a 1,000 watt power amp, and it could be used for whatever application you wanted to use it for. Can anyone explain why certain amps work better for one application and not for another and if there are certain things I should be looking for in a power amp for use with a bass rig? Thanks very much.
     
  2. Passinwind

    Passinwind I Know Nothing Supporting Member

    There are certain features, like limiters, high pass filters, XLR inputs, dual mono switches, and so on, that may or may not matter to you as a bass player. They matter a great deal to me as a sound provider though. But, I might be willing to put up with more weight and larger racking needs than a bass player would be. Fan cooling might bug you if you play intimate gigs, or need to record close to your amp, or intend to use the amp for studio monitors or home theater. Conversely, many players don't want to leave extra rack spaces for a convection cooled amp to breathe through.

    Do you need 4 ohm mono operation as an option? How about 2 ohm stereo? Neither one is something I normally do for PA work, but many bass players need these capabilities.

    You'll notice on Talkbass that input sensitivity gets a lot of attention. Do you already have a preamp selected? You will want to make allowances for matching up a preamp that'll drive your power amp fully, or adding a gain boosting device of some sort inline, if needed. The very popular QSC PLX line comes to mind here. Many preamps drive them well, but some do not. Same for plenty of Crowns though, too.

    Also, a 1000 watt rating is not an absolute, without far more information. 1000 watts at what impedance? What frequency? What distortion? For how long? How much current does the amp draw to output that wattage?

    Finally, there's the never ending debate over old school, Big Iron power supplies, vs. various "digital" schemes (many of which actually aren't digital). I'll leave it to you to search the archives, but be assured, it's not pretty. :eyebrow:

    I own power amps of many flavors. They all work pretty well for bass, when configured reasonably. If you name names, many here will chip in, I'm sure.
     
  3. ADuck5150

    ADuck5150

    Jul 31, 2004
    NJ
    Well while we're at it, out of a BBE Bmax and a Sansamp RBI, which would drive a QSC PLX better? This input sensitivity issue is sorta new to me.
     
  4. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    The BMax has ample output capability to drive a PLX amp. The SansAmp RBI is capable of it after a small modification.
     
  5. pedroferreira

    pedroferreira

    Feb 10, 2003
    Portugal
    Will my Raven Labs PHA-1 need that small modification?
    By the way, can you tell us what it is?
    Thanks,

    Pedro
     
  6. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    Hi Bob,

    I thought that was just the SansAmp BDDI that needed the modification, and not the RBI Rack Version. Was I wrong about that?

    Frank.
     
  7. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Nope, you're right. Sorry, that was me who got things crossed up. My mistake. I was thinking of the BDDI instead.
     
  8. bmc

    bmc

    Nov 15, 2003
    Switzerland
    Hi Bob

    What about the MXR or EBS Microbass preamps? Any mods needed there?

    bmc
     
  9. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    If they can put out maximum output levels of at least about 1.5 volts, then no mods are necessary.
     
  10. rbbonfire

    rbbonfire

    Jan 20, 2004
    This information has been very helpful. Thanks to everyone for your replys.
     
  11. Gregory Bruce Campbell

    Gregory Bruce Campbell

    Apr 14, 2002
    Helena, MT U.S.A 59602
    BEE basses, Morley pedals
    where would I look to find out how to make that modification to my sans amp bass driver
    DI?

    I want them as hot as they can be... I want them directly into each side of both of my
    Stewart 2.1s

    I bought 4 SABDDI boxes and found them too quiet...

    this thread touches on the problem...

    no if I can find how to perform the solution... I’ll be set!!!
     
  12. jonathanl

    jonathanl

    Jan 12, 2003
    Orinda, CA
    I think you can email Tech 21 about it and they'll tell you (or do it for you.)