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Input sensitivity question

Discussion in 'Amps and Cabs [BG]' started by LowEZ, Apr 7, 2014.

  1. LowEZ


    Mar 29, 2011
    Central NJ
    Preamp output spec: "Nominal 0dBV 1V RMS, Maximum +19dBV 9V RMS"

    Power amp input sensitivity is 1.4V RMS.


  2. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    No real issues, but it depends on how you use it. The higher the output from the pre (up until clipping), the better signal to noise ratio.

    But it will only take 1.4V of input at the power amp to drive it to full output when the gain is set to maximum on the power amp. So if you are sending 9V to the power amp, you will not be able to turn the power amp up all the way.

    The best way IMO to deal with this is to turn up the gain at the preamp until it just starts to clip when you are playing as hard as you ever will. Then back it off a bit. This will give you the best signal-to-noise ratio. Then use the power amp to set your overall volume. Watch for clipping at the power amp. If it clips, then you are operating beyond it's real world capacity.
  3. 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
    It means your preamp has more than enough oomph to drive the power amp. As Turnaround said, turn the power amp gain down. Then push a good, strong signal into it so you have fairly optimal signal-to-noise ratio.
  4. LowEZ


    Mar 29, 2011
    Central NJ
    Sounds good. Thanks guys!