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Power Amps Which Configuration?

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by Mark Ward, May 15, 2002.

  1. Mark Ward

    Mark Ward
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    I want to use 3 of my Harmon/Kardon PA2400 Power Amps to drive my front 3 speakers.

    Left and Right (Ref 2.2's) are 4 Ohms loads so according to my PowerAmp's manual I can't bridge the amps. This makes the decision easy LeftHi/RightLow in one Stereo Power Amp and RigthHi/LeftLow in another. Both speakers will be Bi-Amped using 2 runs of Silver Anniversary Cable.

    The Centre channel has more options open to me. My Model 100 is a 6 Ohm load so I could use the power Amp bridged. I only have 1 Silver Anniversary cable running to it, but I have a previously used QED 79 strand still running unused under the floor to the same position.

    So:-

    What's the best option for the centre here?

    1/ Use 1 Channel of the power amp using 1 run of Silver Anniversary cable, leaving the other available for a passive sub later?

    2/ Bridge 2 channels of the power amp together and run through 1 run of Silver Anniversary cable.

    3/ Bi-Amp using 79 Strand for Low Freq. and Silver Anniversary for High Freq.

    I do have another HK PA2400 and a POA-T10 but I want to save them for surround duties once I get a Lex.

    Thanks,

    Mark.
     
  2. garmtz

    garmtz
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    I would take option 2. A good speaker cable is worth more than bi-wiring in most cases and a center channel can use lots of power, because most of the sound is coming out of that channel.

    Don't leave a power amp channel unused for a passive sub. Just use an active one, which is superior anyway.

    You might also listen to another bi-amping solution for your fronts: use one PA2400 for high l/r and the other for low l/r. It is maybe a bit less efficient use of power, but it might sound better (or it might not).
     
  3. Mark Ward

    Mark Ward
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    Hi Garmtz

    I've read many of your posts over the past few days with great interest. I do hope you stay around on here, it's nice to have fresh input.

    You Said:-
    It's funny but that is how I set up my previous configuration but I was advised that I'd get best performance by Running 1 High & 1 Low channel on each amp.

    Previously my Denon's internal amps handled the Hi Freq. Whilst the POA-T10 handled the Low Freq.

    What arguments are there for either solution. I mean, it's easy enough to swap banana plugs around to try, I'm just curious as to what can hypothecially be gained?
     
  4. garmtz

    garmtz
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    Personally, I would never bi-amp with different amps, but using the internal amp on the highs and POA-T10 was the correct compromise. Using one for the left and the other for the right speaker would have ruined your imaging, because the amps probably will not be exactly the same.

    The point is to use amps that are exactly the same for the lows and highs, because they will have the same input impedance (with the same input signal, the same amount of watts out of the amp and linear with volume changes) and have the same tonal balance and phase response.

    Enough of the techno-babble :), the advantage of using one amp for the highs and one for the lows is the fact that you are physically removing any potential influence the bass signals might have on the high frequencies.

    Example:
    When using a stereo amplifier for one channel (highs on L ch and lows on R ch), bass frequencies in the R ch can put a strain on the power supply for a while, influencing the power supply reserve for the other channel.

    When using one amplifier for the highs for the L and R speakers and one for the lows for the L and R speakers, bass signals will be handled by a single amplifier and will not limit power supply reserve for the high frequencies.

    This all MIGHT result in more stable and clearer highs.

    The other method will more efficiently make use of the power of both amplifiers. Most of the power is in the low frequencies and bass is maily monophonic, so you will have more power supply reserve for the bass frequencies, because you are using two amplifiers.
     

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