Turning 3 outputs into 2...possible?

Discussion in 'Amps and Cabs [BG]' started by Rumblefisher, Feb 28, 2010.


  1. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    Hey everyone. Here's what's up:

    I have a Fender 400 PS. Great amp, in love with the tone, very happy. The thing about it is that it has a bit of an impractical feature: 3 outputs, 145 W each, 3 separate transformers (I think), and only handle 4 ohm loads. That means to extract the full power from it, I would need to have 3 cabinets in there at the same time. Granted, the situations I'd "need" 400+ watts are quite few if any, but let's say I wanted to do it... It's like owning a Porsche: no one NEEDS to have that kind of speed and power in a car but it's very nice to know you have it on tap.

    The car I use (not a Porsche :D it's a Pathfinder) to move gear can handle 2 cabinets just fine (2x15s) but it won't take 3. That would mean each time I wanted to use the full potential of the amp, I'd have to make 2 trips to haul all the gear.

    It comes down to this: Is there a way I can turn the three outputs into 2 outputs of 4 ohms? Will there be loss of quality of sound? Is it dangerous?

    I'd rather split the difference of watts (220 watts into 2 cabs as opposed to 145 into 3) and have less stuff to carry while maintaining the ability to use the amp to its fullest (if I wanted to).

    Thanks in advance for your help, I'll be checking this thread often to see what people have to say. Thanks again.
     
  2. Rick Auricchio

    Rick Auricchio Registered Bass Offender

    No. If it has a separate transformer for each speaker output, all you can do is connect cabs like they expect.

    There are a few (rare) combiner-transformer units, but they're very heavy and very expensive.
     
  3. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    Thanks...I was hoping there would be some sort of split/combining cable I could use (I don't have a clue when it comes to things like that, was hoping for a walkthrough). Thank you again for your quick answer.
     
  4. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    There isn't some "3 plugs into 2 outlets" kind of cable I couse use (with the pic representing a 1 plug/2 outlets by my nomenclature)? Would that change the ohm load? Yes, I know I may be asking silly questions but TB has been kind about this sort of thing before. Thanks.
     
  5. Munjibunga

    Munjibunga Retired Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    I'm going to concur with "no" on this one. You're going to blow something up if you use Y cables.
     
  6. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    Of course that's the absolute last thing I want to do...well that and electrocute myself. Thanks gentlemen for saving me time, effort, and having to call the fire department.
     
  7. Grooveman1961

    Grooveman1961

    May 8, 2006
    there is a way to paralell outputs, but it's tricky. Fire up the googler and search for it. I beleive that some early Marshall heads did this.

    I have schemo's, I'll take a look as well.

    Another solution would be a cab wired for the amp head.

    Like a 6x10, 2 8 ohm tens in parallel, each pair yeilding 4 ohms.

    There are of course other combinations.
     
  8. Jazz Ad

    Jazz Ad Mi la ré sol

    It would be much easier to convert a 2 speaker 4 ohm cab into a dual 8 ohm, allowing to plug 2 outputs into a single cab, one channel in each speaker.
    It wouldn't take but a jack and wire.
     
  9. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    If you use something like that you'd be connecting the transformers together, not a good thing. If you want to simplify I'd say get one cab with multiple taps, but then you have to haul around a bigger cab which you may only be using 1/3 or 2/3 of.
     
  10. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    Thanks, I thought about this, but I tend to like 15s. (I know there's much more to it than that but still...)
     
  11. Rumblefisher

    Rumblefisher Supporting Member

    Aug 22, 2007
    Astoria, NY
    Exactly. Seems like the setup I've got is my only option...
     
  12. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Washington, Utah
    John K Custom Basses
    Bob Rissi (who, IIRC, had a hand in the design of the 400PS) still has a few NOS output transformers from the 300PS that he told me would work well in the 400. its a single output tranny that would allow all of its output power to a single output jack.
     
  13. LesS

    LesS

    Mar 3, 2006
    no longer a member
    How about a 3x15 - like the old Kustom or Plush cabinets?
    You could put in a separate jack for each speaker so each of the 3 amps in the 400 PS could drive it's own speaker.
     
  14. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Even if you could, and you can't, the difference between 145 watts and 220 watts is barely audible.
     
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    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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