Reading through the posts here, I realized I've left off some other details. My 2000s does NOT have the bass boost switch - I think this means it's older... i.e. 67 or 68. I recall seeing a '69 date somewhere on the chassis when I had my amp guy go through it a few yrs. back. Also: it has solid state rectifiers, which I am fairly sure were factory done. I do recall that the buzz around music shops back then (early 70's) was that it was something you could get as an option. I can double check this with my amp guy, as I'm sure he knows how to recognize such work.
