I hope this will be my last post about power supplies before I start spending money...
1. Is there a clear benefit to building my own diode bridges? It seems like a toss-up for most people.
2. What does the value of the PI resistors affect, and what would determine if I should use the Optional PI resistors?
3. I assume I should error towards a higher value bleeder resister?
4. I'm planning on building a single power supply for my BA-3 build. Any reason that's a terrible idea?
1. Is there a clear benefit to building my own diode bridges? It seems like a toss-up for most people.
2. What does the value of the PI resistors affect, and what would determine if I should use the Optional PI resistors?
3. I assume I should error towards a higher value bleeder resister?
4. I'm planning on building a single power supply for my BA-3 build. Any reason that's a terrible idea?
Diode bridges are a lot cheaper than a board that holds 4 diodes. Dead switcher supplies in dead appliances are full of ones that can be salvaged. A board for 4 diodes has a place to put the snubber network, a RC filter that prevents the diodes from transmitting RF to your analog circuits. Diode bridges like the 606 are now so small there is no place to put that RC network.
Pi resistors I have used go in C-R-C filters. I only use pi filters when I can't get rid of the hum with a single filter cap. The current draw determines the size of the pi resistor, you don't want a lot of voltage loss in that.
The size of a bleeder resistor is determined by how fast you want the mains cap to bleed down. I usually start at 100 k.
I build a lot of power supplies out of salvage wall or EI transformers. $1 to $5 each usual at charity resale shop. Scrap is a lot cheaper than new stuff. I'll go $35 from ebay for a 44 vac 7 amp transformer for a class AB amp, for example. More traditional voltage would be $70 or more. I build rectifiers & filters on NemaCE board with holes drilled, held off chassis by standoff with #6 screws. Big caps get glued to board, small parts supported by the leads through the board. NemeCE is also called micarta textolite, garolite. Mcmaster sells it, also the screws & elastic stop nuts. Saws up with a hacksaw. Stronger & cheaper than vectorboard with all those holes. Parts-express does have "crossover" board stock that are stronger than vectorboard.
Don't know what a BA-3 is.
Pi resistors I have used go in C-R-C filters. I only use pi filters when I can't get rid of the hum with a single filter cap. The current draw determines the size of the pi resistor, you don't want a lot of voltage loss in that.
The size of a bleeder resistor is determined by how fast you want the mains cap to bleed down. I usually start at 100 k.
I build a lot of power supplies out of salvage wall or EI transformers. $1 to $5 each usual at charity resale shop. Scrap is a lot cheaper than new stuff. I'll go $35 from ebay for a 44 vac 7 amp transformer for a class AB amp, for example. More traditional voltage would be $70 or more. I build rectifiers & filters on NemaCE board with holes drilled, held off chassis by standoff with #6 screws. Big caps get glued to board, small parts supported by the leads through the board. NemeCE is also called micarta textolite, garolite. Mcmaster sells it, also the screws & elastic stop nuts. Saws up with a hacksaw. Stronger & cheaper than vectorboard with all those holes. Parts-express does have "crossover" board stock that are stronger than vectorboard.
Don't know what a BA-3 is.
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It is a very impressive machine, distantly derived from the Ford Model AA but more wheels and tons of armor:
Wikipedia -- The BA-3 (Russian: Broneavtomobil 3) was a heavy armored car developed in the Soviet Union in 1933,
If you are not into heavy metal:
diyAudio Store -- Burning Amplifier 3 Gain Stage Board (BAGS-N). One board works for 2 channels. The BA-3 gain stage is the latest feedback-less "front end" ...