JBL D130 8 OHM w/ '73 Pro Reverb Ohm Question

Discussion in 'Amps and Cabs' started by gaslanyard, Feb 27, 2012.

  1. gaslanyard

    gaslanyard Member

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    Hey,

    I'm looking to play with an extension cabinet using the preamp and power amp section of my 73 pro reverb and preferably a JBL D130. The pro reverb is rated at 4 ohms and the D130 I'm looking at is 8 ohms. I understand that there may be some power considerations by not matching ohms? or will I be okay from going from two speakers at 4 ohms to one at 8 ohms?

    Thanks!

    :confused:
     
  2. solitaire

    solitaire Senior Member

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    That would put unnecessary additional strain on the OT but better a higher impedance than a lower one. Tone would become quiteter and more narrow band. There are impedance matchers so I would get one of those to be on the safe side.
     
  3. mad dog

    mad dog Silver Supporting Member

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    Probably won't hurt anything, but maybe not the best tonally. My '60 brownface pro came to me with a bandmaster PT - at 4 ohms - from the 70s, plus a D130 JBL at 8 ohms. Used a Weber Z matcher to try it unmatched vs. matched. No contest. Matched is way better. That little extra volume and fat you lose in the mismatch could well be the part that makes it sound amazing.
    MD
     
  4. JAP09

    JAP09 Supporting Member

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    If your amp is rated for four ohms then plugging it into an 8 ohm speaker could damage your output transformer. In order for you to achieve a four ohm load you need to have either a four ohm speaker or two eight ohm speakers wired in parallel.
     
  5. smolder

    smolder Gold Supporting Member

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    In conversations with speaker guys recently I've heard said that putting an 8 ohm on a 4 ohm OT, or 16 on a 8 ohm, is one way to get better tone. I'll continue to avoid any mismatch until I hear it improve tone.
     

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