I owned 80s and heard the 30s on a number of occasions. The power differential is noticeable, unless you have very efficient speakers. I think, with the right speakers, the 30s might be slightly better in the bass regions than the 80s, and might be slightly sweeter, but for most part I thought they were very similar, and for my speakers the 80s' extra power was a big difference-maker. Both terrific amplifiers, in my opinion, if you like the Jadis house sound. I would use EL34s or KT88s with them to get the best out of them.
