Since my speakers are 102db, I have a Caddock Axiom Passive between preamp and ST-70. My friend and I did some listening tests and found the passive to be taking away details, so I broke down and purchased the Lo-Gain board. I also upgraded to the Triode PA-060-S Power Transformer as my stocker has recently started humming.
My first impression is the gain is not much lower than with the Hi-Gain running 12AU7's! I also noticed that the high-end is now a bit more harsh with my horns and midrange has gotten lost. This seems odd since I am still using the same tubes with the only difference being the driver board. My guess is the Orange drops were attenuating the higher frequencies? I still have hours to go to burn in the Auricaps, but first impression not so good.
Today I will start to roll some 12BH7's and "Old" Mullard EL34's to see if that helps. Any other ideas from fellow ST-70 aficionados?
Rega P2 - Denon DL-103R
DIY Cinemag SUT - Bottlehead Seduction (Auricaps) - Amperex 7308's
Bottlehead Foreplay III (Auricaps) - RCA Cleartop's
ST-70 - VTA Lo-Gain (Auricaps, 2x100uF & 2x47uF Nichicon KX PS caps) - RCA Cleartops, Mullard GZ34, JJ KT77's
Klipsch RF-7's - Dean Wescott Crossovers