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Before I buy a GK 800 RB ??

Discussion in 'Amps and Cabs [BG]' started by ryco, May 14, 2006.

  1. ryco


    Apr 24, 2005
    I just have just made my 50th trip around the sun. In honor of this achievement my girl of 23 years wishes for me to have a new amp. I have desired a GK for years and I'm thinking the 800 is the one because of its bi-amp feature. I wish it had a little more power, but at my advanced age and the gigs I play I don't need to absolutely blast anymore.

    Anyhow, in looking at the back panel I see it has "speaker lo' = 300w @ 4o and "speak hi" =100w @ 8o
    My question is: can the "hi" run a 4o cabinet safely? I would like to run a 4x12 Marshall for hi end which is a 4o cab.
    Would like to run a Sunn 118 + 112 for the low end. The Sunn cab has an internal x-over if I run it in 4ohm mode

    Sunn cab spec reads:
    700w prog, 375w rms, 4ohm or;
    12" = 300w prog, 150w rms, 8o
    18" = 400w prog, 225w rms, 8o

    I could always just run the amp in bridged mode and just run one cab or the other, but it would defeat the purpose of having a bi-amp amp. In that case I might as well get the GK1001 RB or an Ashdown 500 ABM or an Aggie 500.

    Am I in danger of damaging this amp running this cab configuration? Should I get a 2x12 @ 8o cab for the highs? Am I looking at the right amp? Opinions/education appreciated!

    Thanks in advance, -Ryco
  2. yamaha


    Apr 7, 2006
    You can not Bridge the 800RB. However, the 800rb gives 180 watts at 8 ohms (300 at 4), and 100 watts at 8 ohms (high). This might be pretty great running the sunn biamped and by itself. Select a low x-over frequency (250 Hz about), and this could be a beatiful team. 180 watts to the 18", 100 watts to the 12". I've never tried a 4 ohm load on the 100 watt amp, and don't know of anyone who has, but I know it's not recommended. This will probably damage the amp, as there is not enough resistance (impedance). Good luck.
  3. ryco


    Apr 24, 2005
    Thanks yamaha -

    I can never remember which is the wrong way. If a 8o can run a 4o safely, or if a 4o can run an 8o safely.

    If it can't be bridged, I could just run the Marshall out of the 4o jacks and not use the 8o at all, right? Kind of defeats the purpose of having a bi-amp function though.

    Yeah, the Sunn by itself would be super sweet except it weighs a ton and is a large cab. Built like a mac truck! Oh - my back!

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