Mercury Magnetics OT in 59 RI?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by mt10, Jun 13, 2006.


  1. mt10

    mt10 Member

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    I picked up a 59 Bassman RI that had a PTP board and a Mercury Magnetics output transformer installed in it. When I compared it to my friends 59 Bassman RI with PTP board and the stock OT, his had much more headroom. Is the loss of headroom a characteristic of the MMOT or is it likely something else is going on in the board? The PTP circuit and cap values seem to be in order, we swapped tubes between the two 59's. Mine has Weber p10q's and his has Jensen reissue p10q's. Curious as to what other people think of the MMOT? Thanks
     
  2. Tuberattler

    Tuberattler Member

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    I have a MM in my DRRI and the earlier breakup is characteristic of the originals so it makes sense as the RI amps have more headroom because of the higher voltages and cheap tranny's..you'll find that the MM sound much more complex and are richer in texture than the stock units.. I like mine.
     
  3. pfrischmann

    pfrischmann Member

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    I think the #1 upgrade you can make is speakers #2 is the OPT. I love my mercury stuff.
     
  4. TheAmpNerd

    TheAmpNerd Member

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    Mercury winds some very good sounding stuff.

    Virtually anything I've put them into has been an improvement.
     
  5. mr coffee

    mr coffee Gold Supporting Member

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    and compare speakers first ..

    are you both running the same recifier tube and 12ay7's in the first preamp tube slot?
     
  6. tmac

    tmac Goldmember Gold Supporting Member

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    When you say cap values do you mean power supply caps? Because it may have a lot to do with power supply filtering. The RI have quite a bit more and make them punchier and tighter. I removed one stage on my RI to be more like a old one and it was quite a bit of difference. I put the filter back in. I agree that the MM OT will have a definite effect too.
     
  7. 1guitarslinger

    1guitarslinger Member

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    There are many differences between the 2 amps. The OT is just one of them.

    The speakers will make a very noticable difference.

    Does his have the solid state rectifier installed, or a GZ34?
     
  8. mt10

    mt10 Member

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    Thanks for all the replies thus far, good food for thought.

    When I said cap values, was referring to the signal caps. Didn't think to check the filter caps and if the amps were being filtered differently.

    We did swap out all the tubes both power and preamp so we ruled the tubes out.

    Both have tube rectifiers which we swapped.

    Didn't swap the speakers, yet.

    I guess the main question I am trying to answer is if I should put a MMOT in a 59 Bassman LTD I just picked up. I planned to put in a PTP board but wasn't sure if I should swap out the OT as well since my buddy's 59 with the stock OT had a great bloom to it that mine didn't. It is funny how amps can be just about identical but sound completely different. Today we brought in our 64 6G6-B Bassmans and did a little side by side. Both stock with the exception of filter caps and they sound noticeable different, both sound great just different.

    Thanks again for all the insight thus far.
     

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