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Slave amp

Discussion in 'Amps and Cabs [BG]' started by fcoda, Feb 24, 2003.


  1. fcoda

    fcoda

    Jan 23, 2002
    Nanuet,NY
    The trouble I am having is at a vol level of 5 the amp will clip. The clip light will briefly come on when slapping . Would adding a slave amp give me more power and headroom and resolve the clip issue.
    Using a Hartke 4000 - Hartke 4200 4x10 ( 4 Ohms ) SR5. Also happens with Avatar 2x10 ( 8 Oms )
     
  2. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Does that amp have seperate controls for Pre/Gain and Post/Master volume? If so, turn the gain down and turn the master up to compensate. Clipping always happens at the input gain stage. Don't be affraid the crank the master, it'll be fine so long as the pre gain is low and your speakers can handle the volume.
     
  3. fcoda

    fcoda

    Jan 23, 2002
    Nanuet,NY
    No the amp does not have a pre gain
     
  4. That doesn't sound right to me. I have seperate warning lights for both my gain and master hitting their peaks and the light for the master generally comes on much more often unless I'm slapping or really digging in hard.
     
  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
    Huh? That ain't true. :meh:
     
  6. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I'm all ears Bob. Care to elaborate?
     
  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
    There's not much to elaborate on other than it's easier to clip the output of an amp than the input section.
     
  8. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    OK I'm learning something here.

    So when a power has only one clip light, and it comes on, are we clipping the input the output, either or both?
     
  9. Generally speaking, the output.
     
  10. 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
    That's correct. The output.
     
  11. Bob:

    What happens to the signal when you daisy chain or parallel the LINE level balanced inputs?

    For example, a balanced connection from a preamp is used to drive (3) QSC power amps.
     
  12. 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
    Each input impedance is a parallel connection, so the total load impedance that the preamp sees decreases with each input you add. For example, four 10-kilohm inputs in parallel amount to a 2.5 kilohm load on the preamp output. Each input still sees the same voltage from the preamp. Then it just becomes an issue of what kind of load the preamp output can handle. Some good-quality devices can put out +20 dBu or so into a 600-ohm load, while cheap-quality units might start clipping prematurely driving loads as low as 3 or 4 kilohms.

    All is not lost if you have a preamp or other device with a sound that you love that can't drive many parallel inputs; that's where a distribution amp comes in handy.
     
  13. fcoda

    fcoda

    Jan 23, 2002
    Nanuet,NY
    . I did play a passive bass though the rig last night and I did not have any clipping . So i am fairly sure the input from the SR5 is causing the clip. So ...... can anyone help or offer a suggestion as to how to resolve the clip problem
     
  14. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Are we reasonable in assuming the passive bass has a weaker output than the active. On the surface it seems the solution to your problem is to pad the level of the active bass. Some bass heads have a switch for this. If not, maybe a pedal of some sort that lets you adjust the line level. The effect that immediately comes to mind is an Equaliser but there would be plenty of effects out there with a level adjustment.