Last Feb., I looked at Frank's take on the Dyna St-70 before I purchased Bob's VTA-70. The AVA unit would have cost me about $2200 with state tax and shipping!! I had owned some of Frank's modded gear back in the '80s, and it worked well; met the guy once, nice guy.
But, I liked the idea of building an amp myself, saving money, and using the tubes I already had (EH6550). I don't think the AVA allows much tube choice, but it has gotten good reviews. On the other hand, it's not that tough improving on a 55 year design, esp. when you have spent 30 yrs. doing so. If you want AVA gear, you would be better off looking at his newer designs.
Building Bob's VTA-70 just isn't that difficult! It took me about 15 hrs., which works out to $20/hr. All around, an excellent value. Click on the link below to see my build.
As always, thanks for looking,
Last edited by Gregg R. on Mon Jul 07, 2014 11:53 am; edited 2 times in total (Reason for editing : Added link)