ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: Heath okay here's another ignorant questi... -- 9/2/1997 3:28 PM

Re: Power supply circuits

9/2/1997 10:21 PM
Bruce	Re: Power supply circuits DON'T USE A FULL WAVE BRIDGE RECTIFIER SETUP! Don't use a half wave either.......... You should just use a full wave rectifier. That way you ground the center tap...350VAC 0 350VAC and the rectifiers will see only the 350VAC from each leg of the secondary relative to the grounded center tap. Now you will have 350VAC: times 1.13 for a 5Y3 or times 1.3 for a 5AR4, or times 1.41 for a pair of solid state silicone diodes. SO>>> Now be carefull cause the different rectifiers require a different heater current. 5AR4 in this power supply will draw about 2 amps at 5 volts AC and be about 1.3 x 350VAC = 455V DC unloaded on the B+ supply rail. It will be less then that once you get the tubes in and they start drawing resting current. I would expect to see about 410V DC to 420V DC... or less if you are building a Class A final amp. Hope this helps a little. Bruce

9/2/1997 10:21 PM

Bruce

Re: Power supply circuits

DON'T USE A FULL WAVE BRIDGE RECTIFIER SETUP!
Don't use a half wave either..........
You should just use a full wave rectifier.
That way you ground the center tap...350VAC 0 350VAC and the rectifiers will see only the 350VAC from each leg of the secondary relative to the grounded center tap.
Now you will have 350VAC: times 1.13 for a 5Y3 or
times 1.3 for a 5AR4, or times 1.41 for a pair of solid state silicone diodes.
SO>>>
Now be carefull cause the different rectifiers require a different heater current.
5AR4 in this power supply will draw about 2 amps at 5 volts AC and be about
1.3 x 350VAC = 455V DC unloaded on the B+ supply rail.
It will be less then that once you get the tubes in and they start drawing resting current.
I would expect to see about 410V DC to 420V DC... or less if you are building a Class A final amp.

Hope this helps a little.
Bruce

Replies:

Heath Now I understand what the results w... -- 9/3/1997 9:19 AM