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RBI with a power amp?

Discussion in 'Amps and Cabs [BG]' started by Bass_Dumb, Aug 25, 2004.

  1. Bass_Dumb


    Apr 21, 2004
    Columbus, Ohio
    I recently purchased a Sansamp RBI unit and am wondering the best way to hook it up. I was playing thru a hartke 200watt head straight to two 4x10 cabs before. I was planning on running the RBI to a QSC 3500 power amp and then to my cabs. When running to the QSC 3500 out of the 1/4" Sansamp out on the back of the RBI, my signal keeps getting clipped and distorted. I was told that my signal coming from my RBI would be too hot to use with this sort of power amp. I thought that sounded strange because it seems many of you are running your cabs that way. So, for now i'm running the RBI to my hartke and then to the cabs. It sounds good, but then i'm used to hearing the hartke and don't know if i'm missing out on the RBI's full potential by running it thru the hartke instead of a clean power amp. So, power amp or hartke head? And am I hooking the power amp up wrong? Thanks in advance.

  2. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i'm not really sure about that particular power amp
    if it has adjustable input gain knobs you should be able to adjust it so it doesnt distort
  3. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    What IvanMike said... try adjusting the Level control on the RBI and the input gains on the QSC.

    Have you tried using that QSC with another preamp?
  4. Bass_Dumb


    Apr 21, 2004
    Columbus, Ohio
    no, the only thing i've used the power amp for is playing music coming from a mixing board. it seems to work fine from there.. i'll play with the nobs some more. i thought it seemed strange that the person i bought the amp from said it could not be used with a bass preamp. it seems i should be able to adjust the level to be the same as the mixer's level?

    are there certain power amps that would not work with the RBI unit and is it possible that i have one?
  5. Is it the QSC Series 3 3500? In The Owner's Manual it says that the input sensitivity is 1V, but I'm pretty sure the RBI puts out 1.9V...I may be way off there.

    Something to try: The Sansamp XLR out has a pad for super sensitive mixers, you could use this output to the XLR input of the 3500, then push in the -20 db pad to tame the signal...just something to try.

    It looks like that should be a pretty good amp for bass.
  6. Bass_Dumb


    Apr 21, 2004
    Columbus, Ohio
    thanks mo'phat,
    i had considered that but haven't tried it yet. the problem is that part of the reason i bought the rbi is so i could use the xlr out at gigs to go to the pa instead of using some of the crappy, excuse my language, di boxes that are provided. and i would have a little more control over the pa tone as well.

    does anyone see a problem with running that rbi straight into the hartke head. i'm sure the hartke has its own preamp built in so my question is, am i not going to reep the full benifit of my rbi by doing that... obviously running to the qsc would be the better idea, but unitll i figure that out.. the hartke is what i'm left with.

    thanks again
  7. If the Hartke has a 'power amp IN' jack on the back, you'll bypass the preamp section of the head and only use the power. If not, you can still run the SansAmp either before the main input or through the effects loop and still see the benefits.

    Some players use the RBI as an effects unit in an effects loop to add some dirt. (Geddy Lee.)

    I still think you need to fidget with your SansAmp output compared to the gain attenuators on your power amp. Distortion and clipping shouldn't be happening at all.
  8. Bass_Dumb


    Apr 21, 2004
    Columbus, Ohio
    i didn't think about trying the effects in on the hartke... there is not a separate in on the back unfortunately. i will keep messing around with the qsc.

    thanks everyone!!

    happy bassing to you all
  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
    The vital information is missing: how do you have your gain controls set?