Black Flag JTM45/100 Build and Schemo

[StarTrucker]

Built a JTM100 with the schematics that were available, and now I'm going to update the power supply. I can't find any documentation on the forum or the internet besides one schematic simply called "Hendrix Marshall" which is not correct for this amp.

The amp has the following transformers in it, which I bought from Chris Merren 5 or 6 years ago.

PT : Drake #1202-43 3" laminations, lay down style. 560v B+ 560 -0- 560
OT : EL34 x 4 output (Drake, 1202-119 w/ 100v line)
Choke : I believe it's a 352-114, from the first 45/100s

This is the black flag JTM100 (June 67) configuration as far as I know.

Attached the Hendrix schemo, which has the 270k mix resistors, which are correct for early BF schemos, but still shows the KT66s, and a typo on the PT part number.

Anyone have the correct jtm100 schemo with

PT : 1202-43
OT : 1202-119

 

[playloud]

Take a look at versions 4A + B in the following guide: https://folk.ntnu.no/roef/JTM100.html

You can also see a couple of posts by the author about this transformer combo in a recent thread: https://www.marshallforum.com/threads/pre-black-flag-transitional-100w.139699/post-2508953

560V is going to be hard on the screens of the EL34s (unless running Mullards), but I'm assuming you also have lower voltage taps, given it's a Merren clone?

It seems unlikely the 1204-43 PT appeared in amps of the black flag era, given the 1203-80 was apparently introduced in Feb 67. Never say never, though.