What tubes for ST-70

Your going to find that the KT-77 has a faster, more aggressive bottom end vs. the EL-34. This is also true with the MK-3 amps when the 6550 is replaced with the KT-88. You will also get a bit more power output out of the KT-77 vs. the EL-34. When I had Mk-3's I would also keep them in Genelex KT-88's. That was a while ago when they were still available and reasonably priced. G

I've seen some good things about the remake of the Gold Lion KT-77's. I may try a quad of those next. I've seen them priced around $180-$200 a matched quad. I wonder if they are worth it though?

I have not tried them or tested them so I could not say...G

Well guys my tube rolling is done for now. In the end i settled on a pair of RCA 7199's, a quad of winged "C"' el34's and a Mullard fat base gz34. While the 7199 and el34 tubes were an improvement over the tubes i had to start with, the gz34 brought the amp up to a new level.
I could not belive the improvement i heard after i installed this tube. The bass is much more full, the treble very smooth and the mids are to die for. I'm just glad my local dealer doesn't charge the crazy prices i see on the net for these tubes. But in truth if i spent $150 for this level of improvement i wouldn't be disapointed.

In this case- it's a pleasure to say, "I told you so!"(re: the Mullard in the power supply) If you're handy with a soldering iron, replace the Black Cat coupling caps with something newer(auriCap/Multicap/DynamiCap to list a few good, reasonably priced ones), and you'll find even more music hidden in your discs. Enjoy your tunes. =8^)