Lifco Model 1000 master volume

[clank]

I have a Lifco Model 1000 I am thinking about adding a master volume to get that cranked distortion at a more friendly volume level.
I found a schematic somebody made, but I can't be certain if it is accurate.
Can any body tell me a little about what I have here? I was told it is a copy of a Traynor YBA-1. Does it have a choke?
What would be my best option for the volume mod? The other mod I would consider is a line out to a P.A..
thanks, Jeff

[Steve Conner]

Yes, it has a choke.

That schematic makes my head hurt. A so-called "Post-PI" master volume may be your best bet, and the procedure for fitting it should be the same as for any other 50 watt fixed bias amp.

post pi master volume - Google Search