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Modding an amp for a 2 ohm load

Discussion in 'Amps and Cabs [BG]' started by jock, May 5, 2003.


  1. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Is there anything a good tech could do to make my Ashdown head deliver it´s full power into a 2 ohm load instead of 4 ohms?
    What would have to be changed?
    Approximate price etc???
     
  2. What you need is a trasformer and PV use to market one. There are probably are a few of them still around. I'd contact Peavey.
     
  3. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    you mean it is possible to transform my 8-ohm 125-watt Gallien-Krueger to a 4-ohm (maybe with even more power)?!? :eek: HOW? simply with a transformer? :confused: explain to me, please! you've got me curious, guys
     
  4. This has been several years ago so I may be full of (well you know). But Peavey used to market this big transformer type thing that had taps on both sides of it. On the amp side you would tap into the desired load for maximum power for your amp and on the speaker side you would tap into the actual load your speakers were making. I'm guessing that that is the way an output transformer works on a tube amp anyway. Some of you techies help me out here as I seem to be starting to drown...:(
     
  5. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Yes. Thats right.
    Glockenklang makes one of those. It costs 110 Euro here in Europe. That might be a solution for me. But I can´t find any info on that Glockenklang thingy, just that it is for sale.:confused:
     
  6. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I asked a transformer guru friend of mine about this concept. (he's trained in England and worked for the company that builds Partridge Transformers)

    I asked him if I could use just the secondary of an output transformer to do this and he said that it should work. You'd connect the 8 ohm tap to your amp and the 4 ohm tap to your 4 ohm cabinet or the reverse if you wanted full power into a higher impedance (4 ohm tap to amp, 8 ohm tap to 8 ohm cabinet).

    Keep in mind that the transformer will need to have a high power rating (at least half of the amp's power if you're going 2 to 1 impedance adjustment) which will result in a large and expensive transformer.

    I suspect doing this would also affect the amp's damping factor (ability to control speaker cone movement) and the transformer will most likely limit your amps low frequency response (without having an even bigger and much more expensive transformer)... And big thumping transients could saturate the transformer increasing distortion and mush.

    Since it takes twice as much power to make a noticable volume increase, doing all of this hardly seems worth it...especially if your amp at 4 ohms doesn't put out that much more power than it does at 8 ohms.
     
  7. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    well, even if you say its hardly worth it, it was interesting, though.
     
  8. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    True but how about this scenario:- I've got more speaker cabs than I know what to do with and they're all 8 ohm cabs. My amp is rated at 4 ohms so I can only use 2 cabs at a time.

    If I understand this correctly, I could run 4 cabs (2 ohms) from my amp. Same number of Watts, but twice the speaker cone area, so it should therefore be louder.

    Is this the bit where you tell me the transformer cost about the same as another amp head?
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Well, it might not cost as much as another amp (well, maybe here in the land of cheap used gear* it might) but it would probably weigh more...




    *(not bragging, just acknowledging how well we have it in the US)