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Bi-amping help?

Discussion in 'Amps and Cabs [BG]' started by bass07, Apr 22, 2010.

  1. bass07


    Jan 11, 2009
    Pleasanton, CA
    Can you do a single input with a bi-amp output? I'm looking into getting an Ampeg SVT 4PRO head in combination with my SansAmp RBI, BBE 882i, and a Mesa Powerhouse 1200, and I want to use the bi-amp feature on the SVT and Powerhouse to send the lows to the 15" speaker and the highs to the 10" speakers and tweeter. The wiring is starting to get confusing, possibly unnecessarily confusing. The main confusion stems from the many different kinds of input and output jacks, and all I know for sure at this point is that if I want to bi-amp with the Powerhouse I need to use the "High Output" and "Low Output" jacks to go into the cab. Other than that I'm lost. Any suggestions?

    Here's the link to the SVT 4PRO manual:

    Ampeg SVT 4PRO rear panel:
  2. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    You can certainly take a single input to your SVT4 and get bi-amped output with the highs going through one amp channel and the lows through the other. That's what the "high output" and "low output" are for, as you guessed.

    However, you can't into biamp the Mesa Powerhouse 1200, as far as I can see. It looks like the cab only has a single input, and uses its own built-in crossover to split the high and low signals between the 15 and the four tens and tweeter. So, you can't take two inputs from the Ampeg and send one to the 15 and the other to the four 10s and tweeter.

  3. bass07


    Jan 11, 2009
    Pleasanton, CA
    Oh sorry, that's my bad on the info. It's actually a Powerhouse 1000 and I had the 400W 15" speaker replaced with the 600W 15"... so it's rated the same as a Powerhouse 1200 but with the jack plate of the 1000

    Mesa Powerhouse 1000 jack plate:
  4. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    That must be the older style jack plate and crossover. I don't see any info about it on the Mesa site (they all show the new jack plate), and don't have any personal experience with it. Best guess would be the two jacks on the left would be for high (top) and lows (bottom). So, you'd just take the high output from the Ampeg and plug it in the to jack on the upper left, and the low output from the Ampeg and plug it into the jack on the lower left.

  5. Plstrns


    Feb 4, 2010
    I'd guess the lower right is for the 15, the left lower is 10's, the left upper splits those to stereo- just a wag.
  6. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The response of most fifteens and tens is so similar that there's usually no point in doing so. Running the tens and fifteens off different power amps might be useful for controlling their relative volumes, though.
  7. bass07


    Jan 11, 2009
    Pleasanton, CA
    Well, my guess is the same as yours as far as the speaker is concerned. MY confusion is what the best way to wire the preamps (SansAmp RBI & BBE 882i) in relation to the preamp in the SVT 4PRO and the multiple various input and output jacks is. BBE should be the last thing in the sequence, if possible. Is this a brain teaser for anyone besides me?
  8. Mallard


    Mar 24, 2008
    Per the SVT-4 Pro owner’s manual, in order to run each internal power amp independently (one for high and the other for low) and use the cross-over, you will need two short patch cables and two speaker cables.

    Do the following:

    While looking at the back panel of your amp, note that the top-left corner has a squared off section labeled, “Bi-Amp”, with a “High Output” jack and “Low Output jack”. Plug a shielded patch cable into the “High Output” jack.

    Now, look at the lower/mid area of the back panel and note the section labeled, “Power Amp B”. There are two jacks in that section. Plug the other end of that same shielded cable into the “Power Amp Input” jack.

    Now go back to the top-left section of the back panel and plug your other shielded patch cable into the “Low Output jack”.

    At the lower/right side of the back panel, note the section labeled, “Power Amp A”. There are two jacks in that section. Plug the other end of the same shielded patch cable into the “Power Amp Input” jack.

    The lower left side of the back panel has the various speaker outputs. Plug one end of your first speaker cable into the “Power Amp A” jack and then plug the other side into your low end speaker cabinet.

    Plug your second speaker cable into the “Power Amp B” jack and then plug the other side into your High end speaker cabinet.

    Set the Stereo/Mono button switch to the “out” (stereo) position.

    On the front panel, use the frequency knob to set your desired crossover point (50hz to 1khz). Use the balance knob to adjust the power distribution to both amps. Center position of the balance knob is a 50/50 power distribution. If you want to send more power to the lower crossover side, turn the balance knob to the left (Low Side). If you want to send more power to the high side of the crossover (Hi Side), turn the balance knob to the right. You can adjust 60/40, 70/30, etc or the other way 40/60, 30/70, etc.

    I run my SVT-4 Pro into my Ampeg Isovent, which is a bi-ampable cabinet. I am selling my rig and will put the proceeds towards the purchase of a USA Acoustic 360/361 or will trade it for an original Acoustic 360/361.
  9. bass07


    Jan 11, 2009
    Pleasanton, CA
    Thanks man, I appreciate the help. That clears up a lot. What it doesn't clear up though, is whether I need to hook the SansAmp and BBE directly into the front input (or make another input in the rear) or if I should hook them up via the Effects loop. Would that even make a difference?
  10. Floyd Eye

    Floyd Eye Banned

    Feb 21, 2010
    St. Louis
    Hooking the RBI through the FX loop will leave the preamp stage of your amp in use. Running it through the front input should bypass your amps preamp stage altogether. ( I think that's right)
  11. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    The "other way 'round. Straight in you still use both pre's, through the loop you bypass the 4pro's pre.
  12. duderasta


    Feb 25, 2010
    Tampa, FL
    you could patch out of the bi-amp outputs, through your pres then to the power amp ins.

    Doh for single input just go through the main input use your preamp before the svt, run the rest in the effects loop. you need patch cables to biamp
  13. uhdinator


    Apr 20, 2010
    Umm when you bi amp/split your freqs the system overall will sound better, cleaner, punchier. Run Bi amp all the time.
    if its 2- 410's or a 410, and a 15 cab. it still sounds better.

    you are dividing the workload and when you want more low punch you are not adding low the the high cab so you still get clean high freqs and the low punch. Speakers are more efficient when this way as they are not working as hard cause they don't have to try to reproduce all freqs at once.

    I went bi amp long ago. If I am forced to use one cab for practice I really notice the difference and miss
    the sound I get bi amped.

    When I get a chance I will record my rig both ways and post a couple samples. flip of a switch is all it takes and wow what a difference.
  14. Greenman


    Dec 17, 2005
    Ontario Canada
    I'm sure Bill will appreciate this helpful info. :D
  15. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    When the speakers used actually operate most efficiently in totally different bandwidths, yes. When they operate with little difference over the majority of their respective bandwidths, not so much. Sending only midrange frequencies to a ten inch woofer doesn't turn it into a midrange driver, it's still a woofer.
  16. uhdinator


    Apr 20, 2010
    Ampeg says "The SVT-410HLF also delivers superb top-end, thanks to its 1 horn driver, strategically crossed over at 4kHz."
    (so ampegs 10" drivers are basically acting as a woofer and mid driver) Frequency Response (-3dB): 48Hz-18kHz

    And taking the low out at say 100-200hz won't make them a "mid driver" but won't they be a bit more efficient as they are not trying to reproduce the low and the mids? and the amp does not work as heard either?

    All I know is I got a full range 210 w tweeter and full range 15 cab and is sounds better bi amped at 200hz (lowest amp setting avail) with the flip of a switch both amps are sending
    full range to both cabs and it is not as clean and punchy that way for my rig, it takes the life out of both cabs compared to
    bi amped.
  17. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Taking the lows out of a 410HLF at 200Hz wastes two octaves of its capacity, and at 100Hz one octave. If you don't need what the 410 is capable of in that range you don't need a 410. A 210 would be sufficient, it would have twice the dispersion angle of a 410, and one optimized for use above even 100Hz (too bad there aren't any) could be one half the size of the average 210 to boot. Fully three quarters of the size and weight of a 410HLF is there to support its capability below 200Hz, so if you're not using it below 200Hz there's no point in having that cab.
  18. uhdinator


    Apr 20, 2010
    Was using the 410 specs as an example. But do use a 210 /w tweeter
    and 115 bottom. I leave the tweeter fairly low or off and the x over
    between the two is 200hz. I would go lower but amp only goes as low
    as 200. I like it. Will mic it up soon and record a quick take to
    compare both cabs full range and bi amp and post if anyone
    is interested. Thanks for the insight.
  19. bass07


    Jan 11, 2009
    Pleasanton, CA
    Yeah, I know bi-amping is better, for sure. My buddy (a guitarist, by the way) was using a Marshall 5150 half stack (4x12" speakers) and an ISP Technologies VECTOR SL (15" guitar subwoofer) bi-amped with all the highs and mids going to the Marshall and the lows going to the sub... going from full range in the Marshall to bi-amped was like night and day as far as clarity is concerned.

    The only reason he stopped bi-amping is because he ended up with an Orange 4x12 in a live-in road case (which did wonders for the low end) and needed money, so he sold off the sub.
  20. OGRbassist


    Jan 17, 2010
    I wanna run my SVT4Pro biamp too.
    But how could I run it with another bass amp head?

    My scenerio:
    Run highs to my Ashown 300H-->Ashdown MAG410(8ohms)
    Run lows to my Ampeg 4Pro--->Ampeg 410HLF(4ohms)
    Would I run the cables like this:
    Guitar --> 4pro
    Biamp Hi out --> Power Amp B Input ..then.. Power Amp B Preamp Output ---> Ashdown 300H input --> Ashdown 410
    Biamp Low out ---> Power Amp A Input ..then.. Power Amp A Speaker out ---> Ampeg 410hlf

    Or would I use the transformer balanced line output to get to the Ashdown?

    Any help is good:smug:

    Can I just use regular instrument cables for all of the jumping from the biamp and to the Ashdown head or will I still need to use speaker cable?

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