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800RB bi-amp

Discussion in 'Amps and Cabs [BG]' started by 68Goldfish, Apr 7, 2009.

  1. 68Goldfish

    68Goldfish Supporting Member

    Nov 4, 2006
    Port Orchard WA
    Hey guys. I just got a 800rb from a fellow tb'er. Awesome amp. I'm pairing it with a SWR big bertha (2x15) and a G&L sb-2. I'm just wondering if I should go the extra mile and get a 2X10 so I can use the bi-amp feature. Is there a big advantage to it if you play blues rock and very rarely do any slapping?
    TIA for any info. :hyper:
  2. 62bass


    Apr 3, 2005
    Adding a 2x10 or any other cabinet to the 100 watt output of the second channel will give better coverage and an increase in volume. I've done it a number of times. a 2x10 works well. I didn't bother bi-amping. Just ran the 100 watt amp full range. You can fool around with it when you get your extension cabinet and see which way sounds best-bi-amped or full range.

    If you don't already have one, go to the GK site and download the owner's manual for your amp. It'll answer a lot of questions.
  3. mpm32


    Jan 23, 2009
    I used to run a 2x15 bass reflex cab off of the 300w side and a 2x15 cab off of the 100w side. It sure filled the room. ;)
  4. As I remember it the high amp in bi-amp mode only puts out signals above I think 5KHz. A 2x10 would be a waste as the tens will probably run out of steam before that. Only the tweeter, if fitted, will do anything. As 62Bass has opined running in full-range (and I only just found out that you COULD run the high amp full-range) is your only option.

  5. mpm32


    Jan 23, 2009
    Not so Bassman Paul, not so at all. The newer GKs are voiced for tweeters but the 800RB will happily push a cab with 2x15s. I have done it hundreds of times.
  6. Vic Winters

    Vic Winters Supporting Member

    Apr 20, 2006
    Western NY
    The 800RB has a variable crossover instead of being fixed at 5K like the newer models.
  7. synaesthesia


    Apr 13, 2004
    According to the manual the 800RB has a variable crossover, though the range is not clear. the low amp puts out 200W at 8 oms and hi amp puts out 100W at 8 0hm. Some of the other GK models have a 50W amp at 5Khz.

    Frankly, if you are going to run the crossover anywhere above 500Hz, the 2X10 is a lot of dead weight, you might as well take a box with a 6" + tweeter. If you run it at full range, you will overlap frequencies - that is not technically a good thing from a purist's point of view, but lots of rock players seem to like to do this, probably unwittingly. IMHO, it is not a wise thing to do.
  8. I can see that my memory is completely out of whack regarding this amp. It's no good! I'm just going to have to get mine off the workshop shelf, repair the damn thing and get myself reacquainted with it!

    OK I'll shut up now and have a nap as befits an old fart like me!!!


    P.S. I still say that bi-amping into a 2x10 is a waste of time. Full-range is the way to go! There again I'm a crotchety old fart I is! :)

  9. 68Goldfish

    68Goldfish Supporting Member

    Nov 4, 2006
    Port Orchard WA
    Thanks for the info guys. I think I'll just leave it be with the fifteens for now. If a 2x10 happens to fall in my lap then it sounds like it's probably best, given my playing style (not a lot of slapping and popping) to run it full range.
  10. Crabby


    Dec 22, 2004
    a 210 will be a nice compliment and the 100 watt channel of the 800rb will power most 210 cabs quite nicely at full range.

    I owned this amo for many years and tried bi amping a bunch of times. No matter what settings or speaker configs I tried, the rig always sounded better full range. I miss my 800rb, truly a sweet classic amp.
  11. Can remember right now and the amp is in the rehearsal room, but I believe the freq. range for the biamp contol is 100Hz to 2KHz. In biamp to me anyway the amp sounds deeper on the 300 watt side.
  12. MIJ-VI

    MIJ-VI Inactive Supporting Member

    Jan 12, 2009
    Instead of risking phasing problems by mixing a full-range 2X10" cab with your 2X15", why not use the GK 800RB's 100 watt high amp to drive a 1X15" cab full-range?

    For this to work well with your current 2X15" setup sans phasing issues, the 1X15" would have to use the same make & model of driver mounted in a cab whose internal volume + port design = 1/2 of your 2X15".

    Aside from looking pretty impressive, an acoustically matching 3X15" stack in a line array (+ 100 watts of additional power) would give you ~ 50% more of the bass amp tone that you already love + the advantage of a portable 15" cab for lower volume gigs.

    (However, I expect that this approach would be more ideal with a GK 800RB driving 3 matching 8 ohm 1X15" neo cabs which have a good box size for efficiency.)

    Tres BOOMS! :bassist: :)

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