MidnightArrakis
Well-known member
Nelson: I can only assume that the voltage source shown in your schematic is an AC voltage that is then being rectified by D1 and D2, correct? In my updated schematic I have shown that as a standardized "Voltage Source" schematic symbol. However, I am confused by your nomenclature of (0 - 225 - 60). I do not understand whatever that means. SORRY!!! Maybe "225 Volts referenced to GROUND with a current draw of 60mA"? I just don't know. Maybe I should???Hi Ian,
Yes, the first schematic is from Tape Op, but I can´t see the power supply since I don´t have a subscription to the magazine, but I designed my own, check the attached file, and considerer the grounding that I forgot in the drawing and a 10H choke.
I have shown your D1, D2 and D3 diodes as Type 1N4007's since they are standard, cheap and readily available 1,000V @ 1A diodes that are more than adequate for this application. Personally, I like using "Full-Wave Bridge Rectifiers" in a 4-Pin DIP package that are available in 1A to 3A versions. However, another quick check on your 10H choke on Digi-Key shows 9 models ranging in price from $10.00 to $202.00. I believe you will need to provide some additional information about this choke's specifications before one particular model type can be selected. Is it possible to come up with some other way to offer the needed filtering action here? That's a lot of money just for one part!!! And, you will also need to point out which resistors are -- quarter-watt -- and which ones are -- half-watt -- or something else.
I have also updated the basic audio circuitry schematic with the proper capacitance units (converted to -- uF -- since that is used more often). In addition, your schematic shows various electrolytic capacitors, but you do not show what voltage-rating they need to be. I did a quick check on the 220uF capacitor and the only readily available type that Digi-Key had in-stock is a 220uF @ 400VDC capacitor by either NIGHICON or VISHAY. Since your B+ voltage is shown as being 225VDC and the closest value capacitor on Digi-Key is a 250V unit, I barely know enough to know that that is too close to the B+ voltage to use and also be reliable. So, a 400V capacitor will need to do. It would also be generally helpful to know both the -- type (ceramic, film, etc.) -- and -- voltage -- specifications for the other capacitors shown with your schematic. Otherwise, "assumptions" need to be made and everyone knows the story about "assumptions", right???