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How do you use your power amp??

Discussion in 'Amps and Cabs [BG]' started by ldiezman, Jun 13, 2002.


  1. ldiezman

    ldiezman

    Jul 11, 2001
    Nashville
    Bridged, mono, or stereo? I'm wondering if I running bridged is the best way to go... or if that is a bad idea? I have ordered a Carvin DCM 1500 and not sure whats the best way to get the most out of it. I know running it in bridged mode i'll get the most power... but would it be better for my cab if I run both channels into it??? thanks for your help.. I'm new to the power amp world.. i've always used a combo amp because that is what has been available... but now that I have a fairly steady income... i can begin to go big :D

    Thanks,

    Jim
     
  2. ebozzz

    ebozzz Supporting Member

    May 17, 2001
    Denver, Colorado
  3. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    You *can't* run both channels into one cab ... unless you bridge the two channels together, or unless the cab is amenable to biamping (i.e., separate inputs for hi-lo), which is common with PA cabs but AFAIK not so with bass cabs.
     
  4. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    I use one channel of my GA-1000 for my Triad.
     
  5. jasonbraatz

    jasonbraatz

    Oct 18, 2000
    Oakland, CA
    i run it stereo with a cab on each side. that way if i have to really crank the low end i can turn down the goliath jr so the speakers don't fly out.


    if i had one 4 ohm cab or 2 identical 8 ohm cabs i'd bridge.


    (which is exactly what will happen when i get my goliath sr! muhahahaha!!!)
     
  6. Hugh Jazz

    Hugh Jazz

    Sep 13, 2001
    Atlanta, GA
    I have a slightly different question relating to poweramps:

    Do you run your poweramp wide open (full/maxed out) and control your volume with the master volume on your preamp, or do you run both at levels to get the needed volume (i.e. neither at full...unless you really need to goose them)?
     
  7. ebozzz

    ebozzz Supporting Member

    May 17, 2001
    Denver, Colorado
    I'd like to know what the definitive answer is on that also Hugh.
     
  8. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    Not a definitive answer, but I always run my power amp wide open. I figure it's there to do the work.


    As for my system: I have a Stewart World 2.1. For most gigs I run it stereo into a pair of 8-ohm 2x10 cabs, which gives me ~400 watts per cab.

    For bigger rooms I run mono into a 4-ohm 6x10 cabinet. Running one channel only I get over 600 watts, but if I needed even more power (!) I could bridge both channels and get 2100 watts.
     
  9. jasonbraatz

    jasonbraatz

    Oct 18, 2000
    Oakland, CA
    i run mine full on as well. that way if i need to turn down or up it's one knob instead of 2.
     
  10. incubus2432

    incubus2432

    Mar 21, 2002
    Grafton, Ohio
    I've always run with my amp cranked and just used the preamp master for volume adjustments. When I did the "biamp thing" my preamp had volume settings for each channel so I still had the volumes on the amp maxed and controlled volume through the preamp.
     
  11. I run mine in parallel mode, using the dipswitch on the back (QSC 1850HD). This takes one signal (from my preamp) and splits it to both sides of the amp, 360w per side @ 8 ohms, both cabs are 8 ohms. True stereo mode is having two seperate inputs into both sides of the poweramp.

    I have been cranking the pre-amp and using the poweramp for volume, but having read the above comments I may use the other method as one knob is easier than two :)
     
  12. geshel

    geshel

    Oct 2, 2001
    Seattle
    One thing to know, is that power amps (usually) have zero voltage gain when "cranked". They just provide the current to back up that voltage. So, when you turn down the power amp you are boosting the signal with the preamp then cutting it with the power amp. Not that there's anything wrong with that. :) Actually that's the low-noise solution.
     
  13. ebozzz

    ebozzz Supporting Member

    May 17, 2001
    Denver, Colorado
    I knew that there had to be a legitimate reason why some set their controls in that manner. :) I've been running my amp cranked becuase that's what the instruction from the manual said to do. I'm going to try the other method.
     
  14. Steven Green

    Steven Green

    Jul 25, 2001
    Pacific NW
    I run 2000 watts bridged in 2 8-ohm cabs. I keep my master volume on the pre at 12:00 (which is what Aguilar recommends) and then used the controls on the power amp for volume. This does keep the noise down...
     
  15. Yea, manuals, geez, I knew there was a reason I shouldnt be reading those things!

    Greg
     
  16. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    I'm not sure I understand. Wouldn't the "low-noise solution" depend on which item (preamp or power amp) has the better signal-to-noise ratio?
     
  17. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    The idea, as I understand it, is that you need to get the best S/N ratio as early in the chain as you can. Once you have a given level of noise in there at the beginning, it's there to stay: no amp, no matter how quiet, is ever gonna *reduce* the noise.
     
  18. Brendan

    Brendan

    Jun 18, 2000
    Austin, TX
    Briged. (Pronounced Bridge-ed). Kilowatts baby!
     
  19. geshel

    geshel

    Oct 2, 2001
    Seattle
    What Richard said. Most noise is added in at one stage or another, and gets amplified with the signal at the next stage(s). So doing the amplification early helps increase the overall SNR.
     
  20. ldiezman

    ldiezman

    Jul 11, 2001
    Nashville
    Well the Carvin DCM 1500 I will be using is going to run into One ampeg bxt-410hl cab. it handles 600 watts.. but if I bridge the carvin, that will be pushing 1000. I can turn down the channel so I won't be running wide open.. but will that be ok???