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Volume settings on power amp and preamp?

Discussion in 'Amps and Cabs [BG]' started by Phyrexian, Dec 4, 2002.


  1. I was wandering.

    How do you guys (using a preamp-poweramp rig) set up your individual volumes (both on preamp as on poweramp).

    Hi poweramp volume - low preamp volume?
    Or reversed?
    Does it alter the sound?

    Or when you need a little more output when playing gigs, do you turn up the poweramp volume or the preamp volume???

    Just wandering...
     
  2. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    The norm AFAIK (and also what I do) is to max the volume on the poweramp and use the preamp master volume to control things.

    Alex
     
  3. ... so with a 1600 watt poweramp (example) cranked, you barely touch the preamp volume switch?
     
  4. FunkySpoo

    FunkySpoo Supporting Member

    Feb 6, 2002
    This is how I do it. First I set the power amp to max or almost max. Then I set the pre amp gain as high as it will go without clipping. Volume on bass all the way up. Then use the pre amp master to control overall volume. If I need to EQ things after that then I may need to readjust the pre amp gain.
     
  5. Right now I'm using a Alembic F1-X and a Carvin DPC1000 into a SWR triad. I set the pre-amp volume at about 12:00 and adjust the power amp up and down. At with the volume at 12 I get (I think) the max benefit of the pre-amp tube without a lot of distortion. If I want that (cross roads ) sound like tubes really breaking up, I set the pre-amp on max and turn the power amp way down.:cool: I really love that sound, but, that's just me. With the Power-amp on max and the pre-amp down I get the cleanest hi-fi sound when I need it. :oops: Hope this helps.
     
  6. So...

    with a 500 watt cab and a 1000 watt poweramp, and the poweramp volume on max... no danger on blowing speakers (because the preamp isn't fully turned up?)?
     
  7. On my Eden Nav/QSC rig I do the following:

    Crank the Eden master volume all the way up. Adjust the Eden gain up enough, while avoiding clipping. Then I adjust my QSC volume for the room. Maybe not the "norm" but works better for me.
     
  8. FunkySpoo

    FunkySpoo Supporting Member

    Feb 6, 2002
    Right, the pre amp isn't driving the power amp to full output
     
  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
    Pretty good! That approach will be most likely to give you close to the best signal-to-noise ratio and headroom.

    And yeah, go Blues! Larry Pleau, Joel Quenneville, and Chris Pronger, all former Whalers. }3 ;)
     
  10. What's going on? I was told to use the master for the power amp to control overall volume.

    How come you're using the preamp to set volume?
     
  11. ROFL!
     
  12. who was this directed at? Cause in my situation I am using the poweramp to control the volume.
     
  13. thetaurus

    thetaurus

    May 28, 2002
    Muncy, PA
    okay...so if i put the master volume of my svp pro all the way up, adjust the gain, then control the overall with my qsc rmx 850 (bridged, 4 ohms), i'll be able the get a cleaner sound at a higher volume?

    what's worrying me is that the limit lights on my qsc light up alot when i play lower notes, and the red limit light on my svp also lights up. i play a passive mia jazz bass. i don't want to damage anything. am i doing something wrong, or should i get a more powerful power amp?

    also, bob(qsc)...how should the switches be set on the back of my qsc rmx 850? thanks.
     
  14. That totally depends on the number and/or ohms and/or wattage of cab(s) you are running.
     
  15. thetaurus

    thetaurus

    May 28, 2002
    Muncy, PA
    right now i use a 4 ohm peavey 8x10. eventually, i'll be using a seperate cab setup for different things, consisting of an 8 ohm 2x10 with an 8 ohm 1x15. i'll still be running 4 ohms bridged mono either way.
     
  16. 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
    You don't necessarily have to max the master gain of the preamp. In fact, the presence of a knob is usually a clue that all the way up or all the way down may not be the optimal settings. But get most of your gain early in the signal path, as long as you don't clip.

    If the amp's clip LEDs light up briefly now and then, like every couple measures or something, I wouldn't worry too much about it unless you needed to play louder somewhere. If you're clipping on every beat, maybe consider a higher-power amp.

    I don't know enough about the SVP to tell you anything useful. Sorry. ;)

    Regarding switches:
    Channel 1 clip limiter: ON
    Channel 1 HP filter (4 string): ON and 30 Hz
    (5 string): OFF or ON and 30 Hz
    Stereo inputs
    Bridge mode ON
    In bridged mono, channel 2's settings are irrelevant. Make sure channel 2's gain control is turned all the way down, and use channel 1's to set the gain.
     
  17. ntistt01

    ntistt01

    Apr 11, 2002
    Nashville, TN
    I'm using a Demter HBP pre-amp with QSC power amp. I really couldn't get a decent sound that I liked until I cranked the pre-amp and used the volume on the QSC to control my volume.