Which ClassicTone PT for JMP 100 Build

Discussion in 'Building the Classics' started by dinkyguitar, Jan 23, 2021.

  1. dinkyguitar

    dinkyguitar Active Member

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    Hi,

    I know ClassicTone is going...or gone, but which PT would you recommend provided they are still available.

    40-18024 - general replacement

    40-18053 -($70 more) This also features the upgrade of a flux band and M-6 steel lamination for the ultimate in cool running and high performance!

    Is it worth the extra bucks?

    dinky
     
  2. Matthews Guitars

    Matthews Guitars Well-Known Member

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  3. dinkyguitar

    dinkyguitar Active Member

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    I saw the Merren website...but there's no prices...

    That usually means they will be expensive.
     
  4. Travis398

    Travis398 Well-Known Member

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    If you have to ask...............
     
  5. Chris-in-LA

    Chris-in-LA Well-Known Member

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    Merren is definitely more than Classictone, more in line with Heyboer prices. Send Chris Merren an email, he’ll quote you a price. He sold me a 50 watt OT for 165 + 15 for shipping.
     
  6. bill bokey

    bill bokey Well-Known Member

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    I built a few amps with 40-18053 or 40-18046, great PT !
    If they're still available, go for it !
     
  7. dinkyguitar

    dinkyguitar Active Member

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    Thanks guys....

    I'll send Merren an email.

    Still gathering and deciding which parts I should get.
     
  8. Travis398

    Travis398 Well-Known Member

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    Looks like Tube Depot has both of those in stock.
     
  9. neikeel

    neikeel Well-Known Member

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    If you want the classic Dagnall PT sag of a dimed 100w JMP100 (12 series ‘68 SL then Merren knows what makes it work.
    - if you just want power then get cheapest.
     
    AndyD and _Steve like this.
  10. _Steve

    _Steve Well-Known Member

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    What influences the sag in the PT? Is it the DCR?
     
  11. 2L man

    2L man Member

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    DCR is a value which measuring has a standard.

    How "tight" a transformer coils are wound has most influence how transformer voltage follows current when wire diameter and core iron are same. Current transformers are machine wound over plastic bobbin and plastic insulation and their voltage drops less when current increase than old which were wound looser and paper insulation was used.

    Biggest influence to power supply sag comes if a rectifier tube is used and what type it is. Tube also limits RC filter values.

    When Choke LC filtering is used with rectifier tube voltage comes more stable against current change but also considerable lower and its because choke can "store" energy.

    Also a transformer which is wound for rectifier tube use having a center tab and double voltage but used with two SS diode rectifying will produce more sag than a single output voltage coil transformer which uses a SS bridge rectifier and its because on CT coil only half of the coil delivers current at a time so its efficiency comes lower.
     
    Last edited: Jan 25, 2021
  12. neikeel

    neikeel Well-Known Member

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    The T2562 has a centre tap. It is paper former with copper Q-band. Not a particularly tall stack. It runs a typical bridge rectifier.
    HT is 170189-0-170/180vac rectified approx 480-490v. Sags heavily when pushed.
     
  13. Chris-in-LA

    Chris-in-LA Well-Known Member

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    Who makes the T2562?
     
  14. ibmorjamn

    ibmorjamn Well-Known Member

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    Chris-in-LA likes this.
  15. neikeel

    neikeel Well-Known Member

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