The first is a Sound Values 6GH8 upgrade board that I replaced the cheap caps with orange drops. The circuit is the same as stock except for 6GH8 socket pinout. Includes 2-each NOS JAN6U8A and 6GH8A tubes. $40.00
Next is a replacement '70 board that I rewired to accept 6GH8 types, the rest of the circuit is stock. The traces are not cut and you could replace the tube sockets if you wanted to use 7199 tubes. Incl 2 each JAN6U8A and 6GH8A tubes. $35.00
Last is a totally stock ST-70 used board as removed, no tubes included. $15.00
Prices include shipping! If you want the whole lot, I'll take $75.00 and include 8 more 6GH8 type tubes!