A circuit may not be what you're after but here it is anyway.

http://recordist.com/ampex/schematics/601man/601schem.gif

:w:

um thanks Kev, but already scoped out that web site...

anyone else?

Fletcher from Mercenary Audio would know. If we switch on the "Harley beam" search light, he might see it and drop over here from his own forum with an answer....

Kerlunk! BZZZZZZZZZZTT! FWIP! (Damn it burns hot!)

OK it's on and pointed to the sky above Boston MA... we may have to wait a little while...

Jules

Some people like the sound of old Ampex tube stuff, some don't.
It has it's own cachet if you're going for that 50's or 60's sound.
Don't pay a lot for one though, I wouldn't go more than 50 bucks for the entire tape machine.