Hi all,
I am attempting to understand this PSU2 app. I want to design a power supply for a tube amp that has a B+ of around 350Vdc, and B+1 at about 330Vdc, and my final B+2 (preamp supply) at about 180Vdc. But I have yet to get it to match on my bench test bed. I think the main issues is the load! and the current being drawn.
I have a PT that can supply about 100mA at 325-0-325. Meaning 650V, then after the rectifier I have about 477Vdc.Which is way too high for my 6V6 tubes!. I then use 3 zener diode of 33V drop to bring down the voltage to about 380Vdc. at my first C1 cap. (meaning that is B+). However, depending on the load I put on the PS, changes this of course, and I am reading in the range of about 300Vdc. Right now as a test, I put a 5K resistor at the end of the line.
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My question for you all. is in regrades to current draw. On the PSU designer it shows in the chart, the calculated RMS voltage and current. To get my total current being pulled from the transformer do I add up all these currents? If so, then I have way exceeded the max current on this transformer!
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Additionally, I am totally guessing on how to load down this PS. I stuck that 5K on the end. Its drawing about 30mA at C3. But is that too much? or too little? I know a typical 6V6 push pull amp would put out about 15W at about 125mA. But I am designing this to run at a much lower wattage. Something more like 10W or even 8W if possible.
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See my simulation below. the voltage at C1, C2, C3. would be acceptable, if the currents were correct and my load correct. But with these component values on my real test bed, I am a bit off. Please note, that since the PSU app does not allow you to add in series diodes, I had to fudge the T1 voltage to compensate for a 99V drop, so you will see it listed at 285V, not the 325V it is speced for.
Please help. Do I have the correct values for R1 and R2, R3?
Thanks.
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