First stab with PSD for 6CK4 amp-what have I got here?

[mr mojo]

Howdy folks,

I'm embarking on building my second DIY amp-but this time I'd like to design the circuit as well.

SE, 6CK4s, cathode bias, @ 10wpc.

Here's my first stab at the power supply using duncan's PSD:

I used an 800VCT transformer, multiplied half of the secondary by .707(400)=282v.

After simulation I get 278.8v on R1. I'm guessing @ 10v loss with the output transformer, giving me 268.8v.

Biased for 40ma of plate current, that gives me:
268.8(.04)=10.752 watts, right on target and well below the 13 watt max dissipation rating.

At least if I'm doing any of this right that is!

I subbed different choke values between 5-10-20h and found least amount of ripple with the two 5h chokes. Same with the caps, tried various values and combinations and found the combo shown to give least amount of ripple when zoomed in.

How are things looking so far? Anything I'm way off on? I'd sure appreciate any suggestions or clarifications from the members...

Best,
mr mojo

[kevinkr]

Hi,
PSUD expects you to enter the Rms value, you should have entered 400Vrms per leg or 800Vrms end to end.

Incidentally an 800VCT transformer will give you well in excess of 500Vdc possibly up to 550V with capacitor input depending on transformer winding resistance and load current with this circuit. Unloaded dc should approach the pk value of the 400Vrms waveform which is 640V! Y

You probably want a transformer of about 600VCT for this project. B+ of 300 - 350V is a good choice for a 6CK4.

Kevin

edit: added additional thoughts

[SY]

What's interesting to do is to test the transient response of the supply. Use a constant current load with a step to a 20% higher value after (say) 20 seconds, then look for 3 seconds starting at 19 seconds to see if the supply rings. With realistic values of ESR for your caps and a 40mA constant current load stepped to 50 mA, I'll bet you'll see something you don't like.