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no preamp required?

Discussion in 'Amps and Cabs [BG]' started by GODSBASSMAN, Jan 7, 2013.


    GODSBASSMAN Supporting Member

    Feb 2, 2005
    S. Carolina
    Any one play bass into power amp, no preamp? This would or would not give a more transparent sound? Pros and cons on such a setup? :meh:
  2. Hi.

    To my knowledge there's not many (if any) onboard active electronics that can produce a signal hot enough for the required sensitivity of a regular MI power amp to produce any meaningful volume.

    With a passive instrument it's even less possible.

    Plus, there's a severe impedance mismatch that will colour the sound when doing so. And not in a good way ;).

  3. The pickups in your bass simply do not have enough power to drive the power amp. It takes a preamp to raise the voltage level up to a level that's usable by the power amp.

    A good preamp can be very very transparent...or it can add coloration of its own. Regardless, there must be some sort of preamplification.
  4. My Eden WTDI has bypass button and i have used it to hear what my bass sounds like with out a preamp. Its not good...
  5. it depends on the sensitivity of the amps input.

    I use a power Bag End cab. I've plugged my Sadowskys strait in and it does work. It's surprisingly loud and sounded good but the amps not running near as loud as with a pre amp.

    The same is true for the Sadowskys in passive mode and a cheap J bass.

    I never tried it with the Crown K1 I used to use, but it had an input sensitivity switch so there's no reason I couldn't have. It just didn't occur to me.

    I've seen it done with a QSC also.

    How "good" it sounds would be directly effected by how good the preamp in the bass is and the quality of the amp being used.
  6. sonicnuance

    sonicnuance Supporting Member Commercial User

    Aug 30, 2003
    California, USA
    Engineer & Owner, Sonic Nuance Electronics
    To add to what others have said, you will likely need more gain. I have used a Sansamp BassDriver to drive the poweramp with great results.
  7. Tuned


    Dec 6, 2007
    I can do this with my custom fretless with active Bartolini's into my Peavey IPR and get the power I need for a light gig, but the on-board EQ isn't right for my tone. If it were a more versatile EQ I could get away with it, but I don't show up for gigs with just what I could get away with.

    It's definitely possible to have an on-bass preamp with enough output to drive a sensitive poweramp like the IPR series, but so much of stage tone is derived from the preamp. The exception is actually fretless, where I strive to avoid amp coloration, but I can't see any bass being marketed as "poweramp ready" without fancy amp modeling on-board. The benefits of minimal circuitry would be outdone by the need for versatility.

    GODSBASSMAN Supporting Member

    Feb 2, 2005
    S. Carolina
    Interesting responses here, thanks. Another look at it by me and could you answer this: what is the difference if any in plugging into a power amp vs into the effects return input jack? Are these the same?
  9. amimbari


    May 6, 2008
    Pittsburgh, PA
    that is a good question. I use a Crown XLS with no sensitivity switch so it is set at 1.4v. I doubt my passive bass would even light up one LED on it.

    Never thought to even try it, but now.....
    Tonight I will with a passive and active bass and see what happens and post the results.
  10. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan
    Something as simple as a ART MP pre amp can be had for ~$30. It is just a signal boost, and will power just about any power amp.
  11. your bass will be the wrong impedance and won't have enough drive so results wont be great! I've had good success in the past with driving up power amps with a pedal type pre though!
  12. Godsbassman:

    Depends on how the effect return is placed in the circuit.

    Peavey's is directly before the amp so the answer is yes.

    SWR's is supposedly before the amp BUT there is the effect blend knob to deal with. My experience is that 100% is not really 100%.

    Ampegs doesn't work very well at all. Same with Aguilar.

    I've tried others but other than Peavey they work but you'll be better off plugging in the front and setting the EQ flat, although some are not 100% flat.

    No harm in tring through.
  13. father of fires

    father of fires Commercial User

    Nov 29, 2006
    Chief of Medicine at Damnation Audio
    You could use something as simple as an MXR Microamp. Ultra flat preamp/booster. It'll fix all gain and impedance issues.

    Personally I wouldn't do this unless I had a nice and powerful EQ on my bass.
  14. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan

    This is part of why I love my ART Pro Channel II. It is very transparent, but still has a kick a$$ EQ.
  15. Jeff Bonny

    Jeff Bonny

    Nov 20, 2000
    Vancouver, BC
    Going straight into an SWR Amplite works with no signal loss I can hear. I have to admit though I don't see any advantage to not having an EQ stage just for the sake of "transparency". The only truly transparent sound is silence.
  16. steve_rolfeca

    steve_rolfeca Supporting Member

    The effects return jacks on most bass amps, are quite a bit easier to drive than the main inputs on most pro power amps. They're set up that way so they'll work better with effects.

    Still, effects returns generally don't have enough gain to get the amp anywhere near the limiter when driven straight off your bass, even with an active onboard pre. You'll have sound, but you won't be shaking the rafters.

    The best way to get the transparency you desire, is to quit looking at preamps designed for electric bass, and check out a few mic preamps. It doesn't matter how you tweak your tone controls, even a cheap ART Tube MP is vastly flatter and more transparent than the front end of most bass amps.

    The best you can expect from most bass amps, even with the aid of a scope to tweak the EQ, is about +/- 3 or 4dB from 40Hz to about 18KHz. Most mic pre's are easily +/- 0.5dB from 20Hz to 20KHz, with vanishingly low distortion...

    GODSBASSMAN Supporting Member

    Feb 2, 2005
    S. Carolina
    The only truly transparent sound is silence.
    Is silence really hard?
    Perhaps what we hear as "silence" is just less noise?
    People don't hear themselves 'cause they won't shut up and listen.

    GODSBASSMAN Supporting Member

    Feb 2, 2005
    S. Carolina
    This is what I was looking for. Thanks. So I will catalog the straight to amp as "another usable sound avenue."
  19. Jeff Bonny

    Jeff Bonny

    Nov 20, 2000
    Vancouver, BC
    Depends on its quality and the effort you put into it. It's the most important aspect of music.

    I've spent a lot of time and money chasing uncolored amp rigs so to directly answer your initial question no, not using an EQ stage will not necessarily give you any more "transparency". It will however handcuff you in rooms where a completely flat response sounds like ass. Having an uncolored preamp and speakers works a lot better. Truth is most of it comes down to speaker choice.
  20. DigitalMan

    DigitalMan Owner of seven basses - eligible for 44 TB Clubs Supporting Member

    Nov 30, 2011
    What's the goal? Is it to obtain a particular sound or to save money?