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Outputs on GK preamp

Discussion in 'Amps and Cabs [BG]' started by klamaz, Dec 22, 2005.


  1. klamaz

    klamaz

    Aug 8, 2004
    Virginia
    So, forgive my complete ignorance here, please.

    I've checked the manual, and even asked the guys at Guitar Center, and none of them know an answer for me.

    I have a GK 2001RBP preamp, going into a QSC RMX 850 poweramp. At the moment, I'm putting the DI Out of the preamp into the power amp. This works for now, but it seems that it would be impossible to DI the head and run a cab at the same time. The only other output on it is the Chain out, which seems to be for dasiy chaining multiple preamps together(Can I run that to my poweramp?). Am I missing something, or is the DI really the only way to go into the power amp?
     
  2. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    Well, the manual does appear pretty weak on the -RBP, but it would appear that you should have a "woofer out" and a "tweeter out" which would connect to the external poweramps, and can be controlled by the "woofer master" and "tweeter master" the same as if you had the complete 2001-RB head. Damn shame that there is no back panel picture for the pre in the manual.

    - Tim
     
  3. klamaz

    klamaz

    Aug 8, 2004
    Virginia
    Unless I'm mistaken, there is no woofer or tweeter out on the RBP preamp. At least not that I can find.
    http://img.photobucket.com/albums/v287/killerllamamman/GK2.jpg

    Theres a picture of the back panel for you. As I said, the only output looking things I see are the DI, the Chain out, and the effect send. Any more ideas?
     
  4. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    Odd. I looked at the block diagram in the manual, and it shows what is in just the pre versus the full head, and it pretty clearly shows the woofer and tweeter masters and output paths being in the pre. Perhaps a call to GK would be in order? How the heck can you use the biamp capabilities of this thing (which is clearly has) without output connections?

    - Tim
     
  5. Nigel

    Nigel

    Sep 16, 2004
    Denmark
    I can understand why you're confused. I'm not sure I got it right, but here's what I make of the manual:

    The "chain out" carries a stereo signal (woofer and tweeter), when used with a stereo-jack cable (the tip being woofer and the ring being the tweeter). In order to use the bi-amp feature, you must have some sort of crossover or something to feed two separate power amps (one with the tweeter signal and one with the woofer) from the one stereo cable.

    Are you planning on using the biamp feature?

    I would just use a regular mono-jack cable from the chain out to the input of your power amp, while running the woofer fullrange (not using the woofer hi-cut button). That should work, and I think you're supposed to use the chain out for output.

    If you're uncomfortable in doing so, you could just use a cable from the effects send (line level) to your power amp input. But that bypasses the boost section in the preamp, so I wouldn't do that.

    It certainly can't be true that you're supposed to use the DI out...

    If you're still having doubts, PM Daniel Elliot here at Talkbass. He has been very helpful to a lot of us GK users on the board.

    Good luck with your cool preamp. (I'd like one of those :smug: )
     
  6. klamaz

    klamaz

    Aug 8, 2004
    Virginia
    Thanks guys, I've got it now. I am indeed just using the chain out, and you're right about the stereo thing. I'm not using the bi-amp feature, so I have that running straight to the power amp, hi-cut on the woofer off. Everything's working great now.
     
  7. I suggest that you not bother with trying to run the horn biamp on the RBP. Just use a standard mono 1/4" cable out of the chain out to whatever amp you want to run. The tweeter/woofer thing was meant to be used with a power amp that was never released.
     
  8. So why didn't GK take the bi-amp feature out of the preamp if it can only be used with a special type of power amp that doesn't exist? Just curious that's all.
     
  9. klamaz

    klamaz

    Aug 8, 2004
    Virginia
    Ha, I find that kind of funny, since the biamp feature seems like a pretty big selling point of the preamp(Though I never had intentions of using it).
     
  10. It can be used with a stack of 2001RB heads. So you go from the chain out of the pre into the chain in of the amp and you can string up several of them and control them all from the preamp including powering up and down. It's actually a brilliant bit of engineering, it's just not a useful feature for the average bass player. The rest of the preamp is still great though.
     
  11. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    It's simple dude . . . . you split the output from the chain jack so that the tip lead goes to the bass amp, and the other the tweeter amp. The preamp IS the crossover . . . . . . no special amp required whatsoever.

    - Tim
     
  12. But the crossover is fixed at 5k so the tweeter output is only useful for a tweeter cabinet.
     
  13. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    Well, I may not have said that, but that is what I meant. After all, that pretty much is the definition of biamping, and for a bass guitar application, 5k is a pretty reasonable crossover point. But you do have a point - you couldn't use it to crossover a 15 and a 10 for instance, but then again, that is not the design in any of the GK heads, so (at least to me) is as expected. (For what it is worth, I use a 1001RB-II, with HMS into SBX cabs . . . . ., although setting up pretty much any tweeter equipped cab to run HMS is bordering on a trivial operation.)

    - Tim
     
  14. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Acutally the pre would have been somewhat more useful with a real x-over rather than 1 fixed at 5 k. Having said that, I moved from a biamped (or not) Demeter/Rane/Crown rack to a 1001 RB II running full range. I'm not going back any time soon, I love this amp! My one complaint - I really wish it went to 2 ohms ... even at the ame power ratings. I run a pair of 4 ohm cabinets with an external box to put them in series and the 480 watts I get at 8 is sufficient for my gig. I would rather be able to do without the external box though ...

    The answer of get a pair of 8 ohm cab's instead doesn't work for me as I adore the tonality my existing cab's. Ah well...