Does anyone know how to brige an amp

Discussion in 'Archived Threads 2001-2004' started by Mike Bledsoe, May 29, 2002.

  1. Mike Bledsoe

    Mike Bledsoe Stunt Coordinator

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    I was reading the web sites of Lexicon an Krell on how to bridge their amps but the more I read the more I was confused.
    Could someone Please clear this up for me?[​IMG]
     
  2. Ken Custodio

    Ken Custodio Second Unit

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    Better make sure your amps are capable of being bridged. I read somewhere that most HT amps are not capable.
     
  3. Jeff Hipps

    Jeff Hipps Stunt Coordinator

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    The first requirement for bridging and amplifier requires circuitry, either built into the amplifier or external to it, to invert one channel.

    Second, the amp must be capable of driving the resulting load which will be one half of the original impedance. (If the amp was designed to drive an 8 ohm load, after bridging it would see half that load or 4 ohms).

    Both Soundcraftsmen and Carver once made external bridging adapters to invert the signal, but these would be worthless unless the amp they were to be used with was capable of driving a low impedance load.

    Jeff Hipps
    Sherwood America
     
  4. Norm Strong

    Norm Strong Stunt Coordinator

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    Place the amplifier on the floor. Put a sturdy chair on each side. Now lay a board across the seats of the chairs, and your amplifier has been bridged.
     
  5. Gilles Cyr

    Gilles Cyr Auditioning

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    Hi Mike.
    I have two Hafler Power Amps.
    There is a switch in the back which activates a "bridging" circuitry.
    The Left Output is reduced via a resistor and coupled to the inverted input of the right amplifier, the right input being disabled. The output is then taken off the +Left and +Right sides of the amp.
    Because each channel in effect sees half the impedance of the load, you get the 4 ohm power rating with an 8 ohm load.
    I also own two Carver M1.0T . The 4 ohms rating is 400W/Ch and the 2 ohm rating is 500W/Ch . Strapping in mono mode gives me 800W into 8 ohms, 1000W into 4 ohms. The distortion is also higher.
    One big difference with receiver power amps is the number of transistor/channel . My small Haflers have 4 per channels, the Carvers have 10/channel and my heavy Adcom, 16 transistors per channel. Thus you can drive low impedance loads with no problem. I would be surprised if receivers have more than 2/channel: one in the B+ and one in the B- .
    Regards.
    Horace [​IMG]
     
  6. Ken Garrison

    Ken Garrison Supporting Actor

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    Bridging ain't that hard. If you're just using the amp for something like a homemade subwoofer like I did on my computer in my bedroom, then all you do is twist the right and left outputs together. That works pretty good.
     
  7. Dave Milne

    Dave Milne Supporting Actor

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    Ken,
    Don't do it! That's a good way to destroy an amp. If you have a dual-coil sub, you can wire one coil to each amp channel... but don't tie them together. A very few amps will have a combination of sufficient emitter- or source-resistance and VERY stable feedback loops to avoid meltdown. But I wouldn't risk it!

    Dave
     
  8. Ken Garrison

    Ken Garrison Supporting Actor

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    It's an old RCA Amp from the early 80s. It's been like that for a few months now. No damage at all.
     
  9. Jeffrey Chin

    Jeffrey Chin Second Unit

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  10. JerryW

    JerryW Supporting Actor

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    Jeffrey, LOL!! [​IMG]
    ARAGON OWNZ JOO TU (members of the bridgeable club [​IMG])
     

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