Marshall JTM312H, 1996

[N_Cook]

In for a mechanically broken pot but the rear cover looks nasty to me.
The schematic I have just says 2x 5881 output bottles. In there are
5881WXT , is there squat versions that should be in this model ?
The non-H suffix rear looks similar to this 312
http://medias.audiofanzine.com/images/normal/marshall-jtm312-1995-1997-534172.jpg
The bottle tops touching the metal. Someone has padded out the 3 screws
with nuts and added some distinctly brown , and compressed to <1mm not
high-temp foam , but as the 3 retaining tongues , at the other edge of
this cover, are not now resting on the chassis , its probably not
affording much protection.
Soft silicone rubber pads and some sort of hard standoffs to fit
around the tongues ? I'm thinking some FRPB strip slotted to take the
flat metal tongues.

 

[Phil Allison]

N_Cook wrote:

In for a mechanically broken pot but the rear cover looks nasty to me.
The schematic I have just says 2x 5881 output bottles. In there are
5881WXT , is there squat versions that should be in this model ?

** Yes:

http://upload.wikimedia.org/wikipedia/commons/4/42/Sovtek_5881_vacuum_tube.jpg

The standard Russian 5881 has no base, the WXT is a special ( taller) version for amps that have shark-jaw clamps.

There is a socket made for the standard version with a screw down metal cover - kinda makes the valve bullet proof ;-)



..... Phil