Help with Broskie SS tube power supply

[Viridian]

Hi All,

I was hoping to be able to short cut learning how to design a power supply suitable for the amplifier I wanted to put together and ordered one of these: PS-Tube-SS Kit for Tube Amplifiers Schematic is embedded on that page.

My greatest hope was that the manual for the PS, together with the kit would allow me to build my own power supply for this: Tokyo Metropolitan Life, Tube Audio and ROVER 75 (google will auto translate if the link is opened in Chrome I believe)

But I was pretty disappointed when I received the PS kit and upon reading the manual there was no formula for spec'ing a suitable power transformer.

Can anyone please tell me what voltage transformer I would need to achieve the 207V(or 214V) B+ in the linked 6EM7 schematic?

Would an Antek 5V transformer of suitable VA be suitable? I could use the 5V to rectify for 13EM7 heaters. But then use the second 120VAC winding for B+. Would that work? I know that Mr. Broskie provided for tuning final voltages via resistors but I don't know much more than that.

Any help greatly appreciated.

Erik

 

[JMFahey]

VAC=VDC * .707
so:
214VDC * .707=151 VAC ... anything within -5% +10% (say, 145 to 155/160VAC) will be fine.

Current?
Idle for main tube is shown as 47mA ; I'd ask for 60/70mA capability .

Sorry to say so, that PCB you bought is fine, but overkill, meant for a larger and more complex amp, I fear it might confuse you with its many options you don't need.

For a simple ~200VDC supply, a single filter cap, say 47uF x 250/350V and 4 1N4007 diodes is all you need.

As of rectified filament voltage, can't vouch for that, in any case the 6EM7 is indirectly heated and does not *need* DC .

EDIT: I see you got a 13EM7 instead.
Ok, no big deal, it stays basically the same.
For 13VDC you need a 12VAC winding, which rectified will give you around raw 16VDC, and then CRC filter it down to needed 13VDC .
Suggest a couple 4700uF x 25V capacitors, a 1.5A bridge such as W002 or W004 or 4 x 1N5402 diodes (I assume your amp is stereo, so will need close to 1A DC filaments current).

Needed resistor to drop from raw 16V to filtered 13V will be around 3 ohms, 5W or 10W wirewound.

 

[Viridian]

JM,
Thanks for the help. Really. Yeah, I guess it probably is overkill...

Maybe after getting this kit going I'll have enough confidence to build from scratch.

Thanks again. Looking for suitable transformers now.