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Questions about setting up my new preamp/power amp rig...

Discussion in 'Amps and Cabs [BG]' started by secretdonkey, Dec 20, 2004.

  1. secretdonkey


    Oct 9, 2002
    Austin, TX
    Okay, this will be my first time to use a separate power amp, and I have two questions...

    1. I will be using (for now, at least) my SWR SM-900 as my preamp. I see two options for getting signal into my power amp (Crest CA9). I could use a standard instrument cable to go from the effects loop out, or I could use the XLR DI out, with the switch set to "line" rather than "direct." I have a Radial JDI direct box, so I don't need the DI out. Which should I use, and why.

    2. The Crest CA9 has "binding post" outputs on back. So I guess I'll need cables with naked wire on one end and a Speakon connector on the other. Can I just chop one end off a couple of my existing Speakon cables? Will I find two wires inside of my speakon cable, nicely colored red and black to show me how to hook it up? Will I want to leave those speaker cables "hard-wired" to the back of the Crest? Are my assumptions on this all wrong?

    Thanks in advance for your kind advice, fellow TBers. :hyper:
  2. armybass

    armybass Gold Supporting Member

    Jul 19, 2001
    Just a question because I am new to the whole pre/power amp thing and am getting started in it right now too, but are you using a power amp because you want more power than the SWR can give you?
  3. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    #1 use the 1/4 line out and/or effects out of the sm-900. the xlr can drive a power amp, but the pad would probably need to be turned up all the way.
    # use or make a cord that has speakon on one end, and double male bannana connectors on the other end. you can use bare wire, but it's pretty inconvenient.
  4. jdagger


    Nov 21, 2004
    Just a tip in case it affects you too. I have a SWR Workingman 15 and I drive an external power amp off the line out. I have to because on mine the XLR is pre EQ only.

    Well. always be sure to shut down the power amp first before you shut down your SWR. The collapsing electronics in the SWR on power down (on my head) make a hideous scary noise that could scare the devil himself.

    It sounds kinda like:
    SQEEEEEEEEEEEEEEEEL !!! SKWEEEEEEEEEEEEEEEEK !!!! at a really loud volume.

    Not sure you will be affected the same but thought I would give you the heads up.

    Good Luck
  5. secretdonkey


    Oct 9, 2002
    Austin, TX
    Yeah, I will be driving two Accugroove Whappo Jr. cabs, each of which will take 800 watts. Since the SM-900 nicely handles one of them, I could have gotten a much smaller power amp to drive the other one... but this way I am free to audition new preamps and can change without having to upgrade the amp... plus the power being delivered to each cab will be matched (I'm guessing that the Crest is more conservatively rated than the SWR).

  6. secretdonkey


    Oct 9, 2002
    Austin, TX
    Banana connectors? Cool, if those will work on the "5 way binding post" outputs, that would be wayyyy more convenient than bare wire. Thanks.
  7. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Yup, they do. Banana plugs are one of the 5 ways those posts are designed to work.
  8. Arthur U. Poon

    Arthur U. Poon

    Jan 30, 2004
    SLC, Utah -USA-
    Endorsing Artist: Mike Lull Custom Basses
    Sounds like you have a great amp rig!
    +1 on the banana plug/speakon cables. I'm not too good at soldering, but fortunately I have a friend who is. He made me some speaker cables that are about 5 or 6 feet long with a banana plug on one end and a speakon connector on the other. I believe he used 14 gauge wire.

    The banana plugs slide right into the red and black plugs that screw over the binding posts. It really convenient. There's a single little tab on each banana plug that has 'GND'(ground) printed on it. The speaker cable's negative wire is routed into that so it's easy to make sure you have your speaker cables matching up 'hot' to 'hot'(red or positive) and 'ground' to 'ground'(black or negative) into the back of the CA-9. (Wiring Guru's: Sorry, if my wording on this isn't 100% correct.)

    If wish the U.S. versions of the CA-series amps came with Speakon outputs. Models sold outside of the U.S. do, I can't figure out why they don't sell them that way here. :confused:

    Enjoy that killer amp setup!

  9. secretdonkey


    Oct 9, 2002
    Austin, TX
    Yeah, Arthur, that gets me about the unavailability of Speakons, too. I see you're in the CA9 club, too! :cool:

    Thanks for all of the advice so far, from everyone. :bassist:
  10. NJL


    Apr 12, 2002
    San Antonio
    check yo PM or get on AIM
  11. haujobb


    Dec 16, 2004