Original 18 Watter Mt Question? London John?

Discussion in 'Let's Talk Vintage' started by pleximaster, Oct 21, 2018.

  1. pleximaster

    pleximaster Well-Known Member

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    I have had a discussion with friend about the original MTs of early 18 watter amps... if these Radiospares transformers were only made with "Hygrade" models or if some were originally made with "standard" labeled models as well. He argues that both were used. I am sceptical as the "Standard" lack heater CT and that the "Standard" has 275V HT compared to the Hygrade 300V.

    I have heard both an original 18 watt with known replaced MT (Standard fitted as they are easier to source) and several clones using the Standard and actually prefer the sound of the the lower voltage produce and how the amp preform.

    London John? You are the Combo-King!

    plexi
     
  2. London John

    London John Active Member

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    I've only ever seen Hygrade PT's on original 18w amps, 300-0-300 is the standard HT voltage. These came in two versions, the early with the bell cover and voltage tap, and later without the cover nor tap.

    While we're at it, the OT's were either EL84 (most common) or Heavy Duty. At the very end of production, they also used an OT that I am yet to identify, with a cream plastic bobbin. I've only seen a couple, very late '67 or early '68. Interestingly, this last OT is the best sounding in the 18's I've owned. Nobody seems to know who made it.
     
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  3. pleximaster

    pleximaster Well-Known Member

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    Thanks John!!!!

    Thats my understanding of the MTs as well

    No “standard” MTs

    Interesting fact about the OTs! Could you post a picture of the rare late OT.?

    Best plexi
     
  4. London John

    London John Active Member

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    Here you go.

    [​IMG]
     
  5. pleximaster

    pleximaster Well-Known Member

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    Thanks! Cool!

    If I was guessing maker? Partridge?

    plexi


     
  6. London John

    London John Active Member

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    Doesn't look like anything Partridge made to me.
     
  7. neikeel

    neikeel Well-Known Member

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    Any letters or numbers on it?
     
  8. London John

    London John Active Member

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    Nothing....I've asked all the trannie guys I know.....it's a mystery.
     
  9. ourmaninthenorth

    ourmaninthenorth New Member

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    What do you reckon to the similarities John? Certainly not a definitive answer by any means, but fairly interesting nonetheless.

    Pennine Radio Ltd choke in an early Matamp Series 2000 (1962) ...this model ran until 1968.

    Same style of slots

    [​IMG]

    [​IMG]

    [​IMG]



    Similarly, in a 69 (ish) Orange ORST,

    [​IMG]

    [​IMG]



    Thanks to our mutual pedal Wizard friend for sources on the pictures.
     

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