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using a power amp

Discussion in 'Amps and Cabs [BG]' started by gilbert46, Apr 30, 2005.


  1. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    quick couple simple questions about power amps I havnt been able to answer online.

    1 Do the channels need to be used at the same ohms - ie - can you put a 4 and 8 ohm cab on each channel ?

    I ask because im either replacing my hartke 410 or replacing the aluminum speakers in it, and can go with a 2, 4, or 8 ohm total. Its wired 8 right now, and my benz 115 is 8 to give me 4 total.
     
  2. The 2 channels of a stereo amp are seperate, you can run 4 in one side, 8 on the other.

    If you're amp will run bridged and take a 4 ohm load, bridging with 2 8 ohm speakers gets you the most power out of the amp. Be careful though. If each channel doesn't go down to 2 ohms, the bridge output won't go to 4 ohms, you'll blow the amp pushing it hard like that. Keeping the 410 at 8 ohms gives you the option of bridging later when you do get an amp capable of that.

    Randy
     
  3. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    thats what im thinking as well, i just wanted to verify i could run the two stereo without blowing my new toy.
     
  4. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    I have another question. The input on this amp is XLR, so should i get a DI, or some type of preamp with an xlr out, or just pick up a 1/4 to xlr and be done with it.

    Will the adapter cable cut my signal much? Ive got a me50b and a retro onboard preamp, so I imagine I'll have plenty of signal strenght between the 2 so long as the adapter doesnt do anything funny.
     
  5. Tash

    Tash

    Feb 13, 2005
    Bel Air Maryland
    I find using adapters is a good way to add noise to your signal. If possible I would use a DI/Preamp with XLR out (most models have this feature I belive). If your not able to do that an adapter will work, but you will get some degredation of signal quality. Weather or not its too much is for your ears to decide.
     
  6. 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
    Choose the power amp and preamp that you like. Use a cable with the appropriate connector on each end. There is no degradation of the signal quality in doing that.
     
  7. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    Im reviving this thread. My amp is a crown XLS 402. Im looking to bridge it. The manual says to use a y cable to split the signal and invert the second channel. Where would I find a cable like this, or do the off the shelf cables have one channel inverted.
     
  8. 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'll probably have to make one or modify an existing one. I've never seen an off-the-shelf Y cable that inverted polarity on one side, possibly because the applications for one would be very, very few and far between. You should contact Crown; maybe they would know of a source.
     
  9. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    i just ran out to the store bought a xlr y cable and switched it around. Worked fairly well. Turns out my 15 doesnt like to share 1100 watts :crying:
     
  10. MJ5150

    MJ5150 Terrific Twister

    Apr 12, 2001
    Lacey, WA
    Is the 15 a 4ohm cabinet, and the others 8? If so, that may be the reason it isn't sharing like you expect.

    Nice job on modifying your cable. I had one made for my XLS402 when I had it.

    -Mike
     
  11. gilbert46

    gilbert46

    Sep 21, 2004
    Sacramento, CA
    Thanks. its 8 ohm. Its just not taking the power like I thought it would. Good reason to get an avatar 212 or 115 I think... there is an avatar 115 on sale locally for $150 and i dont have the cash :(