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power amp differences

Discussion in 'Amps and Cabs [BG]' started by millner, Oct 30, 2005.

  1. millner


    Sep 26, 2005
    This is something I've often wondered when considering power amp/preamp rigs. What change would there be in tone if you used a power amp that isnt specifically made for bass amplification (such as QSC or Crest Audio) or a power amp such as the Epifani XP-L90 or Ampeg SVP-1600, which are pretty much bass specific? Is it all essentially the same thing? Now I know there would be a rather major difference if you used a tube power amp but would all the solid state stuff be mostly the same? Thanks a lot for any help!
  2. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    There's mostly two schools of thought on power amps.

    School 1. Any well designed & well built power amp should only amplify its input signal without modifying its tone (as long as it is operated within its design parameters) -- so if you match the gain and blind A/B test them, you should not be able to tell the difference.

    School 2. All audio reproduction devices modify the tone of the original input signal in decernable ways: some are more transparent and dynamic, some less.

    That said, there may be some bass specific companies that 'on purpose' design in a specific tone.

    Most PA or music audio amp builders are aiming for transparency.
  3. thedoctor


    Jun 20, 2005
    Millner, you will find 5 opinions on this for every 3 people you ask. Yorkville, QSC, EdenPro and others will tell you that their basic power amps are up to dedicated bass guitar use; just look at the spec sheets. I disagree with them only to the point that these amps are not tailored for the bass guitar. Do they reproduce bass very well? Yes. Will they make a good bass head if I have all the preprocessing done with a good preamp? Yes. Will they kick Ampeg, Trace, Genz, Hartke (gonna wish I didn't put that in here) butt? No.
    In the real world of road-gigging, the PA system is handling most of the load and the amps you are talking about are small PA amps. When you see the price of a QSC 1850 at $500 less than an Ampeg PRO or a Gall/Trace it is tempting. But you really aren't comparing apples to apples. To put it simply(too late) a quality PA amp will reproduce what you put into it quite well but you need to give it good stuff to make it a good bass amp. I bought ten, yes, ten TubeWorks 1160 amps when they discontinued them because I knew how good they were at reproducing bass with a variety of cab setups. They are only as good as what you feed to them and as a stand-alone bass amp, they suck large. Need to feed them a processed signal to get that "sound" YOU WANT. sORRY FOR RAMBLING BUT i GET ASKED THIS A LOT. Damn, I hate caps lock!
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    PA power amps are designed for transparent sound, i.e., the proverbial "wire with gain." Design techniques have advanced to the point where there is no longer any reason to expect even subtle differences in tone among PA amps, when they are operating below clipping. This does not take away from the art of designing these products, but the frontiers are all in the area of human factors such as size, weight, ventilation, and cost.

    Of course this leaves open the question of whether or not you actually want transparent sound. A bass amp may be designed to introduce some departures from transparent sound, such as mild to heavy distortion and tone shaping. However, contemporary bass amps are increasingly likely to incorporate those features in the preamp, while adopting a transparent power amp design.

    Tube amps are the notable exception, but I claim no knowledge about anything that isn't solid state.
  5. Most PA's have bass put through them, so what makes you think they cannot do well as bass amps? How much different are the requirements for the low end of a bi or triamped PA system and a bass amp as far as the power amp goes?

  6. millner


    Sep 26, 2005
    Ok, so basically if I used a crest, qsc, etc. along with say...a demeter preamp it wont have any effect on the tone, it will just power it BUT if I used an Ampeg power amp it would effect the tone?
  7. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    I don't have experience with Ampeg power amps.

    There are several people here on TB that believe that the big, conventional power supply amps (assuming good design and build) have more 'umph' in the lower registers of bass -- best examples of this type of amp would be the Crown MA-2402 or Crest CA9.
  8. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    +1 to what lo-freq said (and said very well) in both posts.