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Biamping A-85 with Bryston 3B

Discussion in 'Arcam Owners' Forum' started by live2ride, Nov 30, 2004.

  1. live2ride

    live2ride
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    Anyone have any comments about bi-amping an A85 with a Bryston 3B

    I acquired a set of Bryston Powerpac120s (3B equivalent)
    that I'd like to biamp with an existing A85 and was curious to know if there
    are issues with gain matching or impedance matching or ......... ?
    They'd be driving a pair of PMC FB1s.


    Thanks in advance
     
  2. ANDY_DUTTON

    ANDY_DUTTON
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    I don't know the bryston you are talking about. But it is very unlikely that it has the same gain as the A85. So you will need some form of gain matching if you want to biamp using this amp.

    If it is a very good amp, (I don't know) you could try using it as the main amplifer and just use the A85 as a preamplifer.

    Matching the levels between the two amps will probably be quite difficult. If there is no gain trim on the Bryston you will need some kind of line level volume control. You will also need some way of measuring the gain of the bryston. The A85's gain is 31.5dB if the Brystons gain is lower than the A85 you will need a volume control with positive gain. This means it will need to be active (i.e have some kind of power supply) otherwise you can get away with a passive volume control.


    Regards,
    Andrew
     
  3. live2ride

    live2ride
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    Thanks for the feedback Andrew,

    The Bryston Powerpacs120s are 120W mono-blocks with a gain of 29 dB


    Pardon my ignorance in asking.....How would one increase the gain as you've described?:

    "This means it will need to be active (i.e have some kind of power supply) otherwise you can get away with a passive volume control."

    I gather this must be an external power supply with an active volume control??
     
  4. vistisen

    vistisen
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    I have bi-amped my FMJA22 (gain normally 32 dB) with my old AR Cambridge SA200 (AKA ARCAM) which has a gain 29dB. This could be done because the A22 has a low sensitivity button on the back that makes the gain 28dB. I do not know whether your amp has the same feature. The result is fantastic. If you can go for it!
     
  5. ANDY_DUTTON

    ANDY_DUTTON
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    What you need is a adjustable ditribution amplifer or a spare preamp. CPC do a distribution amp that would do the job, I don't know what it sounds like though.

    The part is "PT-102A Audio Distribution Amplifier" from www.cpc.co.uk. Although a second have preamp would work just as well.

    Regards,
    Andrew
     

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