: Thanks to the great pictures here, it now appears that my Sunn 2000s is 69 model. I noticed that the 68 model
: has more tubes. I was wondering why the design change?
: Any advantages??
Well, it's just an example of design evolution--earlier amps utilize tube rectifiers, then a switch was made to solid state versions in early '69, as far as I can tell,in conjunction with the switch in grille cloth patterns. A rectifier circuit has to do with regulating current rather than with amplification of the signal, but it still has a bit of an effect on the sound. An amp with a s.s. rectifier will sound "tighter", notes will be a bit more articulate because the power being called upon by the amp every time it gets voltage from a guitar is controlled in a more efficient manner. Tubes in this capacity, due to their own inherit nature, will "sag" notes, make them kinda mushy, which is actually great for alot of guitar/distortion situations--overdriven guitar notes will "bloom" and sing. Bass, however, is another story. Due to the nature of producing large low frequency waves, ya gotta have alot of power, and alot of control over that power. If you're spitting out a bunch of Rocco and Jaco-style 16th notes, you want the amp to keep up with that kind of an on/off/on/off power surge. Now, on the earlier 2000s, there are two GZ-34 rectifier tubes(same as in a Vox AC30) which reflect that essentially the 2000s is twice the amp that a 200s is(which only employed one GZ34).
