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Does a poweramp just provide power or does it affect tone as well?

Discussion in 'Amps and Cabs [BG]' started by ::::BASSIST::::, Jun 10, 2005.

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  1. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    is the preamp soley responsible for the tone of a pre / power amp rig?

  2. BassikLee

    BassikLee Commercial User

    Feb 13, 2004
    Deltona, FL
    Owner: Brevard Sound Systems
    Power amps are supposed to be, as Bob Lee from QSC says "straight wire, with gain". I have found there are some subtle and some not so subtle differences between different amps. That said, with most any "good" amp these days, the amp's contribution to the overall is minimal.
  3. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    Gee, where's the can of worms JPEG when ya need it?????

    Like B said, in theory, a solid state power amp shoudl affect the tone in a very minimal way. Some say different poweramps sound different, some say they dont. What most of these cats CAN agree on is that the preamp, cabs, bass, strings, etc have a much bigger impact on the tone than a solid state poweramp.

    a tube poweramp has a lot of impact on the tone, but knowing you, you're not about to get a 40+ pound poweramp, and that's what them tube amps weigh, if not more. ;)
  4. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    "but knowing you, you're not about to get a 40+ pound poweramp, and that's what them tube amps weigh, if not more. "

    true is this! :p

    I am basically trying to decide if i should stick w/ my fishman pro platinum as pre or try out a sabddi. Apparently the sabddi is warmer and I assume better for getting a more sweet tone, but i love the eq on the fishman.. there is like 3 bands just for mids. The fishman is quite clean sounding (sterile?) though.
  5. I was away to say, you've obviously not tried a tube power section {torin that is} :p

    I think all in all it doesnt really with SS power amps, not sure about mosfets, because of thier dynamics n such
  6. 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
    An ideal power amp would produce an output signal that is just a perfect larger version of the input signal. A good power amp in the real world does that as nearly perfectly (that is, accurately) as technology allows. And today, they generally can do that pretty damn well, such that it is mostly impossible to distinguish among good power amps solely by sound quality. Think of how difficult it would be to look at a photo and have to determine whether the photographer shot it with a good Nikon, Canon, Olympus, or Yashica. Twenty, 30, 40 years ago it was much more difficult than it is now for manufacturers to design and make super-accurate power amps. In most audio systems, the power amp is the most transparent component in the signal chain.

    Through sloppy or skimpy design and/or manufacturing, it is possible for a manufacturer to make a power amp that doesn't reproduce the input signal accurately. Such an amp could have a pronounced effect on the tone quality of the audio it passes.

    Preamps, OTOH, are designed to allow some degrees of creative manipulation of the signal, through EQ, effects, dynamic processing, etc. They may have certain settings that result in high transparency, but they also are a versatile part of your creative palette, along with your instrument and playing style(s).

    Loudspeaker systems can be and often are designed for certain distinct tonal qualities or for accuracy or a combination of the two. But because they convert an electrical signal into acoustic energy, one's auditory perception is influenced by the acoustical environment and how the loudspeaker is arranged in it. For example, you could have a cabinet that has really great accuracy when you listen to it on-axis, but it will probably sound quite different at 90 or 180 degrees off-axis, even if the signal going into it doesn't change. Likewise, the cabinet will probably sound different, even on-axis, if you put it in a corner of a room versus the middle of the room versus on a 20-foor tall platform in the middle of a large open field.
  7. the dude

    the dude Supporting Member

    Sep 19, 2004
    No. Huge difference between power amps.

    Let your ears be the judge.
  8. PB+J


    Mar 9, 2000
    arlington va
    As you can see, there is a differenced of opinion. I've a/b ed a stewart world 600 and a qsc plx1202. I heard some difference--the stewart sounded deeper, and more "rubbery", while the QSC sounded tighter. Until I switched off the low frequency filter on the back of the qsc, at which point it was almost impossible for me to tell a difference. The QSC has options to filter out the very lowest frequencies, the stewart does not. Once I made them as close to equal as possible, I had a hard time telling any difference, and what difference I thought i heard was so subtle it might have been my imagination
  9. the dude

    the dude Supporting Member

    Sep 19, 2004
    Try reading this.

    Also, in my previous post I should have said "Huge difference between *some* power amps."

    As pointed out by others, a tube vs. SS amp will show big differences. SS vs. SS differences vary by type and manufacturer.
  10. Not in the same way a preamp does, no. But some power amps simply sound more solid and more articulate than others. Going from a Crest V1100 to my CA9 was like going from a Chevy dualie to a Freightliner. Even at comparable volume levels, the CA9 speaks with so much more authority and presence. The power amp doesn't make a lot of difference in the tone, but it can make a big difference in the sound.
  11. cgworkman


    May 14, 2004
  12. 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
    Consider what a power amp does, and it becomes easier to recognize that proper ones should sound the same or very nearly so, and in actuality that is the case. It's not at all uncommon for sonic differences that seem obvious in sighted listening tests to vanish in blind (i.e., sound only) listening tests. (I found it hard to believe myself until I tried it.)

    The human ear's tonal perception changes more in just a few dB of SPL change than than does the sound quality vary among good, competently designed power amps. That's why it's important to evaluate them at exactly equal volumes, because otherwise your ears are fooling you.

    The ear's volume-related variations in response are why many home and car stereos have "loudness" filters that boost the treble and bass, so that at lower volume you can get a tonal response that more closely approximates what you would hear at a louder volume.

    Equal Loudness
  13. Bob Lee had a post awhile ago of why the thicker power amps sound more full and better than the power switching power amps.

    Do a search, it's good info.
  14. Arthur U. Poon

    Arthur U. Poon

    Jan 30, 2004
    SLC, Utah -USA-
    Endorsing Artist: Mike Lull Custom Basses
    +1. :ninja: :bassist:
  15. boogiebass


    Aug 16, 2000
    This debate has been more than adequately aired on TB and is archived for anyone who cares to do a search rather than starting new threads. I see no reason to leave this open as these threads inevitably end in rancor. :meh:

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