My old 4B SST2 sold today, so I decided to do a quick compare between the old 4B SST2 and the new 4B SST2 last night. Testsoftware was provided by
Toto,
Jem,
Waterworld and
Depeche mode.
I listened to two tracks from each album twice, in an attempt to get an as clear and fresh as possible memory from the tracks, while both amplifiers had been on for little over an hour. It took quite some switching back and forth, and I am aware that I am biased because of the knowledge I forked up quite a lot of money for a new 4B SST2, but my listening assistants (girlfriend and daughter) lack this bias, and they both agreed with me.
With the new capacitors in the 4B SST2 the amplifier sounds more controlled, and definitely more detailed in the bass section. The treble also improved, although not as noticably as the lows. The mid has not really changed in our opinion.
The overall sound had become even more detailed, the spacing in the music has become more clear.
I think that, if you have the money available for the change (or for a new amp and then just sell your old one) it is worth the investment. it is an upgrade to an already extremely good product.
Btw, I sold my old amp to a local studio...