Quote:
Originally Posted by regenfreak
Thanks gentlemen.
Allan, thanks for sharing your interesting article.Good job! I like how you can recycle slavaged parts form old devices. It is also interesting how you use the LED in series 12k resistor as a bleeder and over voltage protection during power off.
I dont have any scrap components or transformers laying around, so last night I ordered an inexpensive 240v-110V 20VA step-down transformer. I am going to copy this design using two high voltage transistors ( TIP47 and MPSW42) as B+ voltage regulator with zener diodes:
https://www.tubesandmore.com/sites/d...les/k-101a.pdf
I am not worried about "C" battery as I only build 3-4 valves battery and AC superhets now. With "A" battery, i have been using acid-lead Cyclon 5AH 2V battery, it tends to last for ages. At moment i also use 600mAH Li-ion 9V batteries for B+ with high drain superhet AC valves. |
I bought an old radio power supply for the really old radios using the A,B and C supplies using the zener diode scheme. It was assembled in a fine aluminum enclosure and also includes a volt meter for the filament supply.
It seems like it was designed from the circuit shown on the tubesandmore website.
I have it for many years and use it to test the battery only sets that I restored.
Dave, USradcoll1.
