10 Watt Plexi / JTM45 Tribute amp build

Discussion in 'Building the Classics' started by Guitar-Rocker, Oct 9, 2019.

  1. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    Here is an amp that I built for myself, a Tribute to the early days of Marshall. It's a 10 Watt 6AQ5 power section dual channel amp.

    Flip the left switch to the right and the preamp is a JTM45 Normal channel Hi or Low, and toggle the right hand switch up and it's a JTM45 Bright channel Hi or low input. Flip the left switch to the left and it's a Bright channel Plexi Hi or Low input.

    The power section is cathode bias, built with all of the good parts, ClassicTone PT, MPS OT, ClassicTone choke, pec pots, mustard caps, Draloric resistors, Cliff jacks.

    For the record, I've never put another makers badge on an amp, but since this is a tribute to the glory days, I allowed myself that one time. And the amp stays here for my personal use.

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  2. South Park

    South Park Well-Known Member

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    Nice build what size choke do you have.how Much voltage sag do you get.
     
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  3. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    It would be nice to tribute this to the late Dudley Craven who without him there would not have been a JTM45, also its so nice to see the most basic detail of the red and black twisted pair on the heater wiring which is always a good pointer to proving that it is a genuine original and not a fake as there are many that claim to be but in fact not so.

    Well done and i know that Dudley would be impressed.
     
  4. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    Thank you Ken, I am most honored. A nod to Dudley Craven will be added to the chassis.
     
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  5. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    The choke is a 4 Henry, 50mA, 150 ohm.
     
  6. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    Thanks mate, i will send the pictures to Dudley`s wife in BC Canada, send me a picture with his name on it if you could as i know she will be made up.
     
  7. lespaul339

    lespaul339 Well-Known Member

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    Nice build!
     
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  8. South Park

    South Park Well-Known Member

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    I like the idea of the use of the 5aq5. Nice over drive tones
     
  9. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    Thats a new one on me lol
     
  10. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    With all due respect to the legends of "Loud".

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  11. Far Rider

    Far Rider Hendrixian VIP Member

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    Like all of your builds, a true masterpiece.
     
  12. NewReligion

    NewReligion Well-Known Member VIP Member

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    Beyond Bad Ass Boss!

    Terry, I am really impressed as all of your work & teachings are & have been above reproach. This Amp goes over the top my friend. I am delighted to call you friend and Mentor. No doubt Ken Underwood is pleased with this work. Very professional. I love the ceramic capacitors.

    David Hopkins...♫
     
  13. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    Last edited: Oct 11, 2019
  14. Amadeus91

    Amadeus91 Active Member

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    A work of art, in the truest sense.
    Sir Dudley Craven RIP.
     
  15. neikeel

    neikeel Well-Known Member

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    Very nice indeed.
    How do you find the preamp options in use? Do you switch around much?
    How did you decide on those output valves?
    Sorry if too many questions!
     
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  16. ibmorjamn

    ibmorjamn Well-Known Member

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    Very nice GR ! I finally got a different chassis for my build . I don’t have even 1/100 the skill. I really like the JTM/Plexi idea. I was just going to do the 4 input 2 volume but mine is more on a budget and some of the stuff you have is hard to find. I will try but mine will not compare. I am just trying to copy the circuit only.

    Great work as always.
     
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  17. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    I like that it gives me two distinct options to use, depending on what I may like to use on any given day, and yes I flip back and forth depending on the mood.

    I stumbled across the 6AQ5 several years ago and find it has an amazing ability to sound like a "Big Bottle power tube". The 6AQ5 was designed as an audio power tube and is a alternative in most respects for the 6V6, only in a smaller glass package (7 pin) and less wattage. However it is a loud 10watts at full bore.

    I should note that the 6AQ5 has plate voltage limitations as the plate is next to the outside edge of the glass, and maximum over voltage can burn a hole through the glass.

    www.r-type.org/pdfs/6aq5-2.pdf
     
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  18. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    Just had a mail back from Barbara Craven who is made up with what you have done and she would like to contact you personally. If you contact me direct on keng3sdw@gmail.com i will then give here your email address, if that is OK with you of course.
     
  19. NewReligion

    NewReligion Well-Known Member VIP Member

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    Very Sweet indeed. God Bless you all.

    David...♫
     
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  20. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    D

    Done, thank you Ken.
     

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