With my renewed interest in old-tyme radios, I have decided that I need to have a good adjustable lab bench power supply that will give me filament, B+ and C voltages appropriate for these old radios.
I have located a nice Heathkit supply that has 6.3 VAC at 4 amps for filaments, adjustable 0 - 400 VDC at 100 mA and 0 - negative 100 VDC.
For my SW-3 receiver, the filament voltage is too high, so I will have to build a voltage divider to bring that down to 2.5 volts. Just tested it out and everything is working perfectly.
After a couple years of looking, I have located a National SW-3 receiver that is in good shape.
It came with a couple sets of coils, a bandset coil set for 80 metres and an unknown coil set that was hand-wound by a previous owner as well as two sets of empty coil forms for my own hand-wound coils. Subsequently, I have obtained a bandset coil set for 160 metres.
I am now looking for a period power supply, preferably one of the National "Dog-House" power supplies.
My SW-3 is one of the earlier version 2 receivers. It has a pair of 58 valves (tubes) and a 50 valve (tube). The filaments are 2.5 volt and the B+ is anything upwards of 350 volts though the National power supplies typically supply around 135 volts. Meanwhile, I plan to locate a nice high voltage lab supply to be able to test this little beast out.
Wow, has it really been nearly three months since I updated this blog? Very sorry to be away so long. I have a couple of new short posts to get back into the blogging mindset.
