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wiring (qsc ---> svt 810 E)

Discussion in 'Amps and Cabs [BG]' started by jjs, Nov 11, 2003.


  1. jjs

    jjs

    Jan 26, 2003
    czech republic
    hi!
    After many months spent by "HARTKE suffering" I bought the new rig, that I really love:
    ampeg svp pro
    qsc rmx 1850 Hd
    2x600W/4ohms;2x360W/8ohms
    svt 810 E
    dual mode: two 4x10/400W/8ohms each;
    mono mode: 8x10/800W/4ohms

    the question is: how would you run the cab?
    1. use just one channel of QSC = 600W/4ohms and run the cab in mono mode
    2. use both channels of QSC = 360/8ohms and run the cab in dual mode
    3. bridge qsc = 1800W/4ohms and run the cab in mono mode (I think its dangerous for cab, isnt it?)

    thanx for replies:)
     
  2. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    I'd bridge it, then be careful not to clip it. TONS of headroom, and you won't damage your cab if you don't run it hard . . .
     
  3. g4string

    g4string Supporting Member

    Sep 19, 2002
    Melissa, TX
    when you bridge, turn your QSC all the up and adjust the volume you need with your pre-amp. This is the safest way to bridge. You are more likely to damage your speakers sending a cliped signal to your poweramp (via your preamped turned all the up, and then adjusting the volume on your QSC). If you set your gain settings this way, you will never send a clipped signal to your speakers, and should never have to turn your preamps volume past the 12:00 posistion. You should be rattling the walls if you have to turn your preamp past the 12:00 dentent. Thus, you should not have to worry too much about damaging your speakers. FWIW, no matter how loud or quite you are, always pay attention to your QSC's level led's on the front panel to rest assure that you are not clipping. You can clip at low volumes as well.
     
  4. Stephen Soto

    Stephen Soto

    Oct 12, 2003
    Yeah, don't clip the SVT 8x10 man.
     
  5. 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
    I have to state that it would probably be better (it would certainly be safer) to not turn the QSC amp all the way up unless that much gain is actually needed.
     
  6. g4string

    g4string Supporting Member

    Sep 19, 2002
    Melissa, TX
    Bob,

    You are probably right. However, I was the only guy to ever blow a Bergantino 322 10" driver because I was unknowingly cliping my preamp. I used to leave my QSC at the 11:00 posistion and my pre at about the 3:00 posistion. Although I could never here any distortion or other weird noises associated with clipping, I infact was sending a cliped signal to my QSC. Mr. Bergantino himself said the safest way to run a pre-power setup was to crank your power amp all the up and adjust your master gain with your preamp. Bob, I think you will find that a lot of guys run thier pre-power rigs this way. I know that there is a better way to achieve unity gain and all that jazz. I just think that this is the safest to run while bridged mono.
     
  7. 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
    Clipping your preamp won't blow your speaker unless it causes the power amp to put too much power into the speaker. And the more your power amp is turned up, the more likely that would be.

    It's safer to turn the amp down.
     
  8. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    I have to agree with Bob on this one (as usual), but not being "engineeringly inclined", I have some real world experience to offer.

    When using my 3002, I usually leave the power amp level at about a 6, and adjust my preamp's gain accordingly. Typically only two of the four LED's on the 3002 light up, not approaching the "clip" indicator. However, at one of last weekend's gigs I toyed around a bit, and backed the preamp's gain way down, and turned the power amp's level all the way to 10, netting the same volume. The result: same volume, but the QSC's LED's were running higher, and when I slapped the clip indicator kept sneaking on and off. Again, this was with the SAME net volume onstage.

    Of course, your mileage may vary . . .
     
  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
    Eric, you were running louder because the amp was putting out more signal, as indicated by the LEDs. (BTW, full gain is at 32, not 10.) It might not have been much louder, or even noticeably louder than before, but that's what it would be.
     
  10. g4string

    g4string Supporting Member

    Sep 19, 2002
    Melissa, TX
    Bob,

    How would your reccomend I adjust my gain settings? I use a PLX-1602 bridged in mono with a Demeter HBP-1. I mostly use a pair of Aguilar GS112's or on occasion a Bergantino 322. I play a Lakand 55-94 with the overall volume of the bass at about 3/4 of the way turned up. Any info would be helpfull. Thanks!
     
  11. 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
    Just the general rule of thumb would be to keep your signal as strong as possible right up front (as long as you don't clip anything) and use less gain at the end (the power amp), but enough to get the sound level you want.

    Obviously, you need to adjust for different situations, but that's what knobs are for. If you prefer to adjust your volume on the bass, then leave yourself some room to maneuver on the bass's volume control(s).