im seeing a manual New st-70 board and i see many difference with a old board. (I worked looking at the older model board i think
)
new st-70 board say:
Eyelet
#4 & #5 to Pins 1 & 2 of the left power take-off socket
(Note 1) (i have soldered eyelets 4 and 5 to pin 2 and 7)Eyelet
#24 & #25 to Pins 1 & 2 of the left power take-off socket (Note 1)
(i have soldered eyelets 24 and 25 to pin 4 and 5)Eyelet
#15 & #16 to Pins 1 & 2 of the right power take-off socket
(Note 1) (i have soldered 15 and 16 to pin 2 and 7)
old board say: Step 28: Connect two wires from
pins 2 & 7 of the EL34’s with the green filament wires going to them
(right side looking from bottom of amp) run these wires to
eyelets #4 and #5 on the driver board. Before
soldering to eyelets #4 and #5 also connect a second set of wire into the holes which we will connect to eyelets #24 and #25 on the driver board
Step 29: Connect two wires from pins 2 & 7 of the EL34’s with the brown filament wires going to them (Left side looking from bottom of amp) run these wires to eyelets #15 and #16 on the driver board.
in a new board manual i see a
NOTE 1:
NOTE 1: These are the input tube filament connections. A stock ST-70 uses the front panel power take-off
sockets as a tie point for the input board tube filament wiring. Many amplifier modifications use these
socket holes for input jacks or other purposes. If the tube filament power is not present on these jacks or the
jacks themselves are not present, then the filament wiring can be run (as twisted pairs to reduce hum) from
the output tube filament connection (EL34: pins 2&7). The phase inverter position (V2) now has extra flexibility to use tubes with different pinouts, to use 12AU7, 12BH7, ECC99 solder a wire from J1 to J2 and make your filament connections to eyelets 24 & 25, to use 6CG7, 6922, 7308, or 6DJ8 do not jumper J1 and J2 and instead make your filament connections to J1 and J2 and ignore eyelets 24 and 25.