[Ron Ramirez]

Ron, would it be advisable to run the model 70 sets with a Variac to get the correct operating line voltage? What line voltage were these sets designed around?

You could use a Variac, but a lot of guys use a transformer setup to "buck" the line voltage to a lower level. Maybe Ed Locker or someone else who has done this will chime in here with details. (I haven't built one, but I have one that Ed built.)

At the time the Model 70 was built, 110 volts was apparently the norm, with 115 being the upper limit. Now, 125 is the norm, and mine has run as high as 128. Old radios do not like this higher line voltage.