The type 50 has a 7.5 volt 1.25 amp filament. The Sharp regulator used in the original TSE could not go above 7 volts on it's input, so tubes like the 811A and the 50 were not an option.
The TSE-II uses a Microchip regulator that can eat up to 26 volts. This enables a wide variety of tubes that were previously not possible. I have not tried the 50 or the 811A because I don't have any.
The Schottky rectifier specified in the parts list was chosen for it's low voltage drop is should be good for AC input voltages up to about 10 volts.
Some of the filter capacitors specified in the parts list are rated at 10 volts. These may be OK for a 7.5 volt transformer depending on line voltage and the actual transformer output voltage. Measure the voltage across them.
This leaves only the voltage setting resistors that need to be changed. Note that R1 and R2 in the TSE-II schematic are reversed from the Microchip data sheet. For 7.5 volts R1 should remain 100 ohms, and R2 should be 505 ohms, or whatever's closest in an available part. As always, measure the filament voltage before installing any tubes!
The TSE-II uses a Microchip regulator that can eat up to 26 volts. This enables a wide variety of tubes that were previously not possible. I have not tried the 50 or the 811A because I don't have any.
The Schottky rectifier specified in the parts list was chosen for it's low voltage drop is should be good for AC input voltages up to about 10 volts.
Some of the filter capacitors specified in the parts list are rated at 10 volts. These may be OK for a 7.5 volt transformer depending on line voltage and the actual transformer output voltage. Measure the voltage across them.
This leaves only the voltage setting resistors that need to be changed. Note that R1 and R2 in the TSE-II schematic are reversed from the Microchip data sheet. For 7.5 volts R1 should remain 100 ohms, and R2 should be 505 ohms, or whatever's closest in an available part. As always, measure the filament voltage before installing any tubes!