I ordered a new VTA ST-70 kit from Bob and built it last weekend and I wanted to post something about my experience.
It took me about 14 hours to complete the build and it worked the very first time. I had a few questions before I received the kit and Bob was great answering my questions. This forum is a great source of information. The ST-70 sounds great on Klipsch RF-35's using the Sansui 7 for the preamp. The sound is definitely better than the Sansui 7's 36 watt per channel amp (20-20KHz) about the same amount of power. 35 Watts of power seems plenty for my setup (speakers and room size). The rectifier tube went bad after a few hours playing and I ordered a couple spares and now after several hours of play it seems very stable. I put in the two 1n4007 diodes in the rectifier tube as a precaution.
I had another minor incident, after plugging in all the tubes after making the modification one of the power tubes didn't light up. I discovered one of the filament socket pins wasn't making contact so I pushed them together a bit and that solved that problem. A suggestion, don't wiggle the tubes in, push them straight down and pull them straight up when removing so as not to bend the pins. It looks like I can't import a photo directly, have to use a link? So a photo next time.
I'm very happy with the ST-70 and many thanks to Bob for his help.