I just picked up an earlier 2000s off Kijiji - the guy who sold it to me speculates it was somewhere between 69 and 72. The knobs have a more primitive look, just a little black notch on a cylinder sorta thing. It's by far the most versatile amp I've ever seen, aside from the weight issue. I tried all sorts of things through it before I bought it - double bass (my primary instrument), P bass, 3 different guitars (Tele, Jaguar, Mustang), and charango with B-Band. Everything just came out sounding like itself in the best way possible, and there is plenty of wiggle room in the EQ so I can even take all the bass out and do some chicken pickin' on guitar or something if I want - though I never hear any frequencies lose all their response, which is a great sign. This is the only amp that has made my double bass arco sound better - most if not all others make it sound worse, with the possible exception of my Acoustic Image.
My only complaint is that the bass knob on the EQ is quite imbalanced - all the difference is made from "all the way down" to about 9 or 10 o'clock, and every other position after just sounds the same.