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Setup Question...

Discussion in 'Amps and Cabs [BG]' started by 69charger, Nov 9, 2000.

  1. 69charger


    Nov 9, 2000
    Hello Everybody!

    This is my first post so here it goes...

    I just bought an SVT4 Pro and I also have the 810 and 215 Classic Series cabs. Most of the time I am playing in large enough clubs to use both, but when I can't I would just use the 810. I noticed the 810 has two input jacks (2)-1/4" and (2)Speakons. Is the 810 just two 4x10's stacked on top of each other? The amp has 2 output modes, Stereo(Biamp), or Mono(Briged). I'd like some expert input on this and it looks like this message board is loaded with it.

  2. This is based on memory, so correct me if I am wrong.

    With the SVT-4 you have two options. You can run the amp in stereo with one cabinet for each channel, or you can run both cabinets off the brigded Speakon output. SLM makes a cable that allows for this (1 Speakon to 2 1/4" phono), or you can make one yourself. Pretty easy. However, I believe that both of your cabinets are rated at 4 ohms, which would create a load of 2.6 ohms total. This is bad. I think the SVT-4 has a minimum load of 4 ohms. If you had two 8 ohm cabinets, this would work fine.

    The long and short of it:

    If you run one cabinet per channel, you should be fine. Go for it. If you run both off the bridge, you may fry your new amp.

    If you only use one cabinet, use the bridge mode. You should be able to blast everyone else off the stage.
  3. Doug


    Apr 5, 2000
    Buffalo, N.Y.
    The Ampeg 810 cab is not like the SWR 810 where it's basically 2-410 cabs in one. Do not plug two amps into this cab. If your'e going to use the one 810 cab, get yourself A heavy gauge speaker cable with the Speakon plugs and run your amp in the mono bridge mode. Here's how the ends are to be connected. This comes right from Ampegs website in the FAQ section.

    What kind of speaker cable is required to mono bridge my SVT-IV PRO?

    The prefered cable is 12 gauge with Speakon to Speakon connectors. Be sure to wire the Speakon on the "amp" end for +1 (positive) and +2 (negative). On the "cabinet" end wire the Speakon for +1 (positive) and -1 (negative). It is a good idea to label each end so there is no confusion on the gig.

  4. membranophone


    Mar 19, 2000
    Madison, WI

    The formula for finding the impedance of speakers wired in parallel is:

    1/(total impedance) = 1/(cab impedance) + 1/(cab impedance) ...


    1/(total) = 1/(4 ohm) + 1/(4 ohm)
    1/(total) = 2/(4 ohm)
    1/(total) = 1/(2 ohm)
    total = 2 ohm

    the impedance will be 2 ohms.

  5. Speedbird

    Speedbird Supporting Member

    Jul 10, 2000
    Northern Virginia
    Dude: OT! '69 Charger, (just like the Duke Boys) cool/drool! Back in the day (before wife/kids/career) I had a band & a '68 Charger! Ever seen the movie "Bullet" with Steve "McQueen? After I saw that, I bassicaly sold my sole for one. White, Hard-top, R/T, 440 magnum, ect. I bought it for $3K, spent $2K @ Mopar Perf., couple $k's on misc. restoration items & $2K on the suspension (that stuff is mad expensive, esp. the "K" frame). But, it passed everything but gas-stations! Sorry to ramble, just vicariously living through you dude (T.B.com just keeps on giving!). Savor it while you can.

    I remember the trunk was big but a 8x10" & 2x15", DAMN!

  6. the impedance will be 2 ohms.

    Sorry. Like I said, working off memory. In any event, the total impedence is less than the 4 ohms the bridge mode is rated at, so the point is moot. I know some combination produces 2.6 ohms. Is it one 4 ohm cabinet plus one 8 ohm cabinet?

    In any event, I do commend you on your accuracy.

  7. membranophone


    Mar 19, 2000
    Madison, WI

    1/(total) = 1/(4 ohm) + 1/(8 ohm)
    1/(total) = 3/(8 ohm)
    total = 8/3 ohms = 2.6667 ohms


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