Hi Steve. I can't honestly say, because I did the wiring upgrade and changed sources and the wiring upgrade - all at the same time.
However, I can say from my prior efforts (before all this chnge) that the "5-star GE" 12AV7 is very good. it made a HUGE difference over the stock tubes, much quieter and much better bass. I would also say the much vunted telefunken 12AT7's were not as good a fit to my ears - a bit too aggressive. I bought the Mullards based on Allan B's recommendation, and they hit the amp with all the other changes, so i wouldn't be able to say what they specifically added to the equation. I guess could roll the stock back in, but dont plan on it, given all the other changes and the need for the Berning to break in.
here's an older thread on others' experiences.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1083225301&read&keyw&zzberning
However, I can say from my prior efforts (before all this chnge) that the "5-star GE" 12AV7 is very good. it made a HUGE difference over the stock tubes, much quieter and much better bass. I would also say the much vunted telefunken 12AT7's were not as good a fit to my ears - a bit too aggressive. I bought the Mullards based on Allan B's recommendation, and they hit the amp with all the other changes, so i wouldn't be able to say what they specifically added to the equation. I guess could roll the stock back in, but dont plan on it, given all the other changes and the need for the Berning to break in.
here's an older thread on others' experiences.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1083225301&read&keyw&zzberning