Biamping with no pre-outs

Discussion in 'Archived Threads 2001-2004' started by ChadF, Dec 28, 2002.

  1. ChadF

    ChadF Extra

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    Looking for a little help here from all you HT gurus out there. I have a pair of Acoustic Research S40's that I have setup as my mains that I would like to eventually biamp. I currently have all 5 HT speakers connected directly to a Sony STR-DE485 receiver which has no pre-outs (to add an amplifier). Down the road I am going to upgrade to a pre/pro, but I do have an old Onkyo A-7070 amp that I am not using. Is there anyway of using the Sony receiver and Onkyo amp to biamp the AR's even though the Sony doesn't have pre-outs?? I'm saving up for a pre/pro, but I'm already hooked on catching the biamp bandwagon! Any thoughts or comments would be greatly appreciated!
     
  2. Rob Rodier

    Rob Rodier Supporting Actor

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    Not really.

    You might be able to find some kind of active/passive box that accepts speaker level inputs and converts them to rca but I would say it is not worth it. You really need the pre-outs.

    -rob
     
  3. ChadF

    ChadF Extra

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    Thanks for the input Rob. Yeah I was playing around with it last night and I hooked up the Onkyo directly to my Toshiba DVD player using the L/R audio out on the Toshiba to the Aux in on the Onkyo. Then I biwired my AR mains to the L/R A & B terminals on the Onkyo. With this setup I can listen to CDs with only the mains and still play DVDs and have surround sound sound with the Sony still driving the center and rear channels via a digital coax from the Toshiba directly to the Sony. I don't have to swap any cables but it is difficult to balance the soundstage switching back and forth from CD to DVD.

    I could also probably use the Minidisk out on the Sony to an empty RCA input on the Onkyo to make use of the Sony's tuner for radio listening since the Onkyo is only an amp. Cd's sound really nice with the extra power with this setup, but I don't think it is going to be worth the imbalanced soundstage when playing DVDs. Oh well, its always fun to test things out in the everlasting quest for HT nirvana!
     
  4. Tom Brennan

    Tom Brennan Screenwriter

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  5. Craig_Kg

    Craig_Kg Supporting Actor

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    Yes you can if you make linouts to convert the speaker level output voltage to source level. You can achieve this with a 10 kOhm resistor in series with a 470 Ohm resistor across the receiver speaker terminals (one of these for each channel you need to source out) which gives a 20 to 1 attenuation. You then use the voltage across the 470 Ohm resistor as the input to your amp. The speaker terminals can still be used to drive the speakers.

    I did this with my Sony 675 receiver before I upgraded to a receiver with preout and the sound was not bad at all. You do want to be careful to make sure nothing shorts (which may blow up the receiver) and that you don't source across the 10 kOhm resistor by mistake (which may blow up the amp) - I put the circuit in a little plastic box with speaker leads in and RCA sockets out.
     
  6. Guy Usher

    Guy Usher Supporting Actor

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    Yes but what are you going to use for a crossover or do you run each driver"Full range"
    Sounds like too much sugar for a dime to me.
     
  7. ChadF

    ChadF Extra

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    Guy, Craig, and Tom.....I appreciate all of the feedback! I think I am going to stick with my current setup and hold out for the biamping until the budget allows for an equipment upgrade. Of course it still won't keep me from tinkering and wondering "what if?" [​IMG] Hey Tom, interesting site. Looks like your club guys really get into the hobby. I'd love to hear one of those rigs in person!
     
  8. Craig_Kg

    Craig_Kg Supporting Actor

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    He could be talking about passive biamping using the speaker crossovers (the commonly used term, which I find objectionable, is "fool's biamping"). Anyway, just substituting the external amp for the front speakers will increase the output capability of the system as the receiver power supply won't have to cope with those.
     
  9. Guy Usher

    Guy Usher Supporting Actor

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    Bi-Amping is a little tricky for stereo. Bi-Amping for 5 or 6 loadspeakers can get very complicated and expensive if done correctly. IMO there are many other things you can do that will give you more return for your money and for your efforts.
    Bi-Wiring is crazy like 2 garden hoses, 1 has the highs, 1 has the lows, turn on the facuet and what happens water comes out, IMO I will stop here. . . .
     
  10. Michael R Price

    Michael R Price Screenwriter

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    "Fools bi-amping"... sounds like something I just tried. And no, it didn't work very well. I say, don't bother unless your amplifiers have the sound characteristics you want to suit to their individual ranges... or if you have an active crossover. And there's also a big problem getting the levels to match.
     

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