ST 70 best sounding version?

FYI: Bob Latino sells his wares on http://www.tubes4hifi.com/, along with Roy Mottram who sells pre-amp kits and customizations to original Dynaco 70s.

Regarding recitfer tube vs SS, Bob’s amp can run either without issue. In addition, there are a lot more upgrades to the amp beyond the power supply (output transformers, better caps, upgraded chokes, high precision resistors, driver circuit changes, a fully modern tube compliment, upgraded chassis, to name but a few). So IMHO Bob’s amps are really just modeled after the Dynaco ST70--his VTA 120 is a fully modern amp that is much closer to the Rouge Magnum and other modern tube amps that can run KT88s and KT120s (and now even includes an auto-bias board option.....)

Full disclosure--I own Bob’s VTA 120--super product with super support (something you might want to consider). Great supporting community as well.

Agreed that the ST120 can use a tube rectifier and produce full output, just not a 5AR4. Mr. Latino makes it pretty clear in the post below:

http://dynacotubeaudio.forumotion.com/t479-st-120-rectifier-choices

4 KT88 or 6550 are just going to require more current than the little rectifier can put out at full voltage. If you don’t need full power than save some money and buy the ST70. Note that the original Dynaco MKiii amps use two 5AR4s to provide the B+ voltage to the same 4 KT88s.

 "....just not a 5AR4."  Noted :)

Looking at the specs, Mullard GZ33 would get you full power out of 4 KT88. A little spendy perhaps. It would be nice if the Russians would reissue that tube.