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Output Voltage for Ampeg BSP

Discussion in 'Amps and Cabs [BG]' started by Masher88, Mar 1, 2006.


  1. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Does anyone know if Ampeg's BSP (Billy Sheehan Preamp) have a low output voltage or something like that? It doesn't seem to get my QSC PLX amp as loud as my old preamp did. I'm running the gains and masters pretty high and it's not pushing the amp very much. Maybe it needs a new tube? Anyone have a clue?
     
  2. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Anyone? Help!
     
  3. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    What output are you using?

    Clean/mix is the output to use.

    Don't try to drive the power amp with the balanced outs, they are really just DI outs.
     
  4. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Yeah, I'm using the clean/mix output jack. It just doesn't seem to put out much power to the amp. Is this normal? I've heard that some pre's have a lower output than others.
     
  5. It's probably the same thing as with my SVP-CL... the output is not as loud, because they made it to fit THEIR SVP-1600 (for some obscure reasons that I didn't find valid besides marketing advantage)... there was a thread last year that I started and even the then AmpegInsider explained it.
    You can see it by the specs, it's called the output sensitivity. The low output of the SVP matches the low input sensitivity on the SVP-1600. :rollno:
     
  6. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    The PLX3002 needs a stronger signal to drive it to full output. You can see the input sensitivity comparison by model at QSCaudio.com

    The good news is that the input sensivity of your PLX can be increased by changing a pair of resistors per channel. Any QSC service center should know how to do it.
     
  7. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    You don't have the input "pad" button depressed do you?

    If you suspect the tube, try plugging your bass into the effects return and see about output level from there...
     
  8. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Yes, I have the "PAD" button pushed in. My G&L has active electronics. VERY HOT Actives, to be precise. I tried turning the pad off and it just overloads the input and the clip lights come on at any gain setting. Thanks for the info about the Output Sensitivity being low....had I known this, I probably wouldn't have gotten this preamp. What a retarded thing to do...make a preamp that is almost incompatable with 99% of the amps in the world.:rollno:
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Actually, the input sensitivity of your PLX is low meaning it takes more signal than average to drive it to full output.

    As I mentioned, it's a common, reasonably priced modification to match the output of your BSP to your PLX. Any QSC service center should know how to do it. They only have to change four resistors...

    Assuming that you really like your BSP, just get the mod done on your PLX and be done with it. If you replace the preamp in the future with something hotter, you'll just have to take it easy on the level controls of the PLX...no further worries or other modifications necessary!