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rewiring svt1540

Discussion in 'Amps and Cabs [BG]' started by s-curl, Mar 16, 2006.

  1. s-curl


    Mar 16, 2006
    Los Angeles, CA
    I have an SVT1540 Classic cab. 1x15 + 4x10 and a horn. On the back is 4 inputs: 2 8ohm full range, and 2 4ohms for bi-amping.

    My question is if it's possible to rewire this cab so that I have 3 seperate 4 ohm loads? I'd like to keep the horn connected because i sometimes use this cab for an Arp Odyssey, but I'm open to losing it if I must because I turn it off when playing bass. I recently bought a Fender 400ps and want to take full advantage of the 3 outputs.

    Also, if anyone has recommendations for replacement speakers, I wanna hear some opinions.

    One more thing...I haven't opened it up yet, does anyone know if this cabinet has 2 seperate chambers? It's from the mid 90's
  2. It's not possible to have 3x4 ohms. You could have top 2x10 8 ohms, bottom 2x10 8 ohms and 1x15 4 ohms.

    AFAIK its 3 seperate chambers. 1 chamber for 1x15 and each 2x10 is in its own chamber like what happens in the 8x10.

    What's the Fender 400ps ( could not find it on their website ) . Do you need to use all 3 outputs to get full wattage or are they 3 outputs in parallel?
  3. s-curl


    Mar 16, 2006
    Los Angeles, CA
    Thanks for the info.

    How about replacement speakers? Anyone know what would work well in this cab to give me the 3 4ohm loads I badly need?

    The Fender 400ps is a 435 watt all tube amp from the early 70's. The problem is that it's an odd design and the way to get the max power is use 3 4ohm loads each at 145 watts.

    here are some pics of a freshly restored unit, unfortunately mine is not as beautiful :scowl:

    Those are the 3 outputs on the left, and there's only one configuration: 3x145 watts.
  4. With the Fender 400ps do you have to use all 3 outputs or is it possible to only use 2 of them safely. I'm asking since I have that SVT1540 cab and use it with an SVT400T ( 2x200@4 ohms ) solid state amp. The thing is soo loud sound guys hate me. I'd hate to hear what 435 watts tube would sound like. I once used a "Skunkworks" SVT throu it in a very very large hall and when every body had left the rehersall I tried turning the volume up . I got to about two thirds and couldn't take anymore.

    If you decide to replace the speakers remember that the 4x10 section of the cab is sealed. Other people on this board that understand it better than me say that speakers designed for sealed cabs have a different specs to those of ported cabs.
  5. s-curl


    Mar 16, 2006
    Los Angeles, CA
    I used to have a IIIpro (that I never really liked) and it's hella louder than that was. Sounds like a vintage SVT using just 2 of the outs, which fyi is safe.


    I just hate the idea of wasting 145 watts, I wish the outs could be run in parallel. It's off getting retubed and I can't wait to get it back.

    Do you still have the stock drivers in your cab? I prefer the tone of the 15" but it's weak. Pops all the time. The 10's don't give as warm a tone, and I always turn off that damn horn.
  6. Have you checked out the Yahoo 400ps group? It's pretty slow but a well worded post will get you answers pretty quick. As for trying to get 3 4 ohm loads in a small package, I'd think you'd need a bunch of new speakers for that cab. Might be cheaper to get 3 small 4 ohm cabs. I think someone here mentioned running one with 3 bag end cabs to good effect. Or maybe an old Sunn 612 or 610 with a bunch of new speakers and customeized wiring. The pain in the @$$ factor for this amp works against its coolness factor to keep the amp affordable. If it was easy and simple to own it would COST like a vintage SVT!
  7. I still have the stock drivers. The sound of the 10's are very rough to my ears and I need the 15 to get a warm sound. One problem with the 15 is because its ported it's easy to get a muddy sound. Also when using the 15 it seems very deeply voiced, if that makes any sense. This can be a problem for more light weight gigs. The sound 2 feet in front of the cab might be decent but if I check what it's like 15-20 feet infront it can have no definition. Sound men hate the horn. For some reason I never can hear it when I'm next to it but if I listen 10 feet infront of the cab I hear a terrible hiss. It does nothing usefull. Even with the threeway switch turn to -12db it still can be heard.

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