Bluesbreaker replacement OT ohm question.

Discussion in 'Amps and Cabs' started by Tylenol Jones, Apr 10, 2015.

  1. Tylenol Jones

    Tylenol Jones Member

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    Bought a BB with a Mercury Magnetics O45RS-L OT. The strange thing is the ohm selector switch was set to 16 while my buddy says his ohm meter measured 8.

    Here is a picture of the OT in question in my amp.

    [​IMG]

    Here's the PDF with all the technical info on that OT ; http://mercurymagnetics.com/images/transformers/schematics/OT/O45RS-L.pdf

    Just got my Fryette PS and want to plug it in but don't want to damage anything. How should I plug the BB? As an 8 or 16 ohms speaker output?

    Here's how my speakers are currently connected.

    [​IMG]

    Left speaker (when looking from behind).

    [​IMG]

    Right speaker.

    [​IMG]
     
  2. garret

    garret Member

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    Assuming the speakers are 16ohm then yes, they should measure at 8ohms the way they are wired. Was that ohm reading your buddy did across the speaker input cable?
     
  3. support

    support Member

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    Would help to see what's going on inside...

    [​IMG]
     
  4. Tylenol Jones

    Tylenol Jones Member

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    Yes.

    They're the stock G12M Greenbacks.
     
  5. Tylenol Jones

    Tylenol Jones Member

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    Everything is stock except for the tubes (all Tung Sol 12AX7 and KT66) and the OT.

    That's what I was told by the previous owner. I have the bill for all the work. Nothing else is mentioned except for OT installation.
     
  6. support

    support Member

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    Seeing the OT wiring colors on the impedance selector and power tube sockets will confirm if the original 4/8/16 format was retained or changed. That particular MM OT can be configured a number of ways.
     
  7. Tylenol Jones

    Tylenol Jones Member

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    Ah. That makes perfect sense and also explains why the documentation didn't specify an output ohm rating.

    I'll open it up later tonight and post pictures. Please check back tomorrow morning for an update as I won't be able to post until the wee hours of the morning.
     
  8. support

    support Member

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    I don't know what you're doing on Saturday morning, but I'm pretty sure mine starts with a couple of advil...:drink
     
  9. Tylenol Jones

    Tylenol Jones Member

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    LOL!!!
     
  10. Tylenol Jones

    Tylenol Jones Member

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    As requested, here are the pics.

    Wires from the OT for reference.

    [​IMG]

    There appears to be 6 wires ;

    - Black
    - Blue
    - Red
    - White
    - Green
    - Brown

    At the top, in the middle, is where the collection of wires come from the OT.

    [​IMG]

    Please let me know if you need any extra pictures as I'm keeping the amp open until I can figure this out. Last thing I'd want to do is damage my amp or my precious new Fryette PS!
     
  11. RussB

    RussB low rent hobbyist Silver Supporting Member

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    show the impedance switch wiring
     
  12. Tylenol Jones

    Tylenol Jones Member

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    I'm a newbie who doesn't know electronics, so please bear with me.

    Where would I find this?
     

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