PSU Output: Tubecad PS-1 Question

Having a bit of a hard time recently getting in contact with John at Tubecad. Want to order the PS-1 power supply kit for a 12B4 preamp I am building but have an important question first.

My preamp requires ~40mA of HV current (CCS, 20mA per channel).

The PS-1 page on the Tubecad website PS-1 High & Low Voltage Regulator Kit advertises the output as 50mA.

The documentation for the build (see attached) advertises up to 100mA HV current. Which is it? The current is limited by the semiconductor devices and their heatsinks. I am just not sure how to interpret their data and specs to see what kind of current output I can expect.

50mA is a bit too close to the 40mA I need, but 100mA gives me lots of margin.

Thanks!
 

Attachments

  • PS-1 Rev A.pdf
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Re-read page 17 of the pdf that you attached. Recommended current draw is 20mA to 100mA. I use the PS-1 power supply at 300V output and draw 50mA with absolutely no issues at all. As you probably already know you will need to size the transformer appropriately for the current draw, method of rectification, and some head room.
 
Re-read page 17 of the pdf that you attached. Recommended current draw is 20mA to 100mA. I use the PS-1 power supply at 300V output and draw 50mA with absolutely no issues at all. As you probably already know you will need to size the transformer appropriately for the current draw, method of rectification, and some head room.
Thanks for your input

Page 17 is what had me confused. It states up to 100mA but the webpage advertising the PS-1 quotes 50mA. Glad to here your experience, that clears things up.

I am going to order the PS-1 with 1.5" heatsink along with the toriodal transformers that John also sells/recommends so I should be good to go.


One other question:
What is the purpose of the two 1R resistors in series with the caps on the regulator output (R9 & R10)?
 
I would also recommend non conductive thermal paste and mica spacers (or silpads) to isolate the high voltage from the heatsinks and give better thermal transfer. If i recall, the kit does not come with anything.

I'm not 100% sure, but if I understand it correctly R9 and R10 help to keep the output of the regulator stable. Without the resistance to shield the capacitors it may oscillate the voltage output. I wondered the same thing when building mine and that was the only reason I could think of. Perhaps someone else could clarify?