Power Transformer ratings

[glen]

I need a 300-0-300 power transformer for a 6n6p - 300B SET. So I will draw 30ma (6n6P) +100ma (300B) per channel. That's a total of 260 mA. I think it is best to double the mA draw for the transformer size.

This is a full wave bridge with damper diodes.

So when Hammond rates their transformer at 600VCT 287 mA, this means how much current available with a full wave bridge ? INOW is this transformer big enough?

Thanks

[battradio]

Its big enough , just remember that there will be voltage drop arcos the damper diodes , also Antek make nice transformers http://www.antekinc.com/details.php?p=730

[DeathRex]

When I went to school there was the half wave rectifier with one diode, the full wave rectifier with 2 diodes and the bridge rectifier with 4 diodes. There wasn't a full wave bridge, at least that I remember. I keep seeing this and I get confused between the 2. But I'm guessing a full wave bridge has 4 diodes. So you're going to rectify the full 600 VAC leaving the center tap unused, that will make a lot of DC for a 300B SET, 700VDC? And take 4 damper diodes. So I'm probably wrong.

You're probably using the center tap to make some 380VDC with 2 damper diodes. If you're doing that then AC current in to the rectifier = DC current out. Like Mark said you'll be fine with 27ma to spare.

[glen]

I meant full wave with 2 rectifiers not brdge with 4.

I guess what I was getting at does 600VCT 287 mA = 300-0-300 @ 287mA x2 (574) ?


I was always told to have double the current capacity.

[kheper]

I need a 300-0-300 power transformer for a 6n6p - 300B SET. So I will draw 30ma (6n6P) +100ma (300B) per channel. That's a total of 260 mA. I think it is best to double the mA draw for the transformer size.

This is a full wave bridge with damper diodes.

So when Hammond rates their transformer at 600VCT 287 mA, this means how much current available with a full wave bridge ? INOW is this transformer big enough?

Thanks

With a full wave cap input design and that transformer, it will yield ~425Vdc@287ma.

You would NOT want to run that transformer as a full wave bridge with the 300B.

Antek makes a 2 x 300Vac@333ma for $38.50. With the secondaries in series, you would get ~425Vdc@333ma as a full wave design.

http://tubes.nekhbet.com/power.html#fulw

http://www.antekinc.com/details.php?p=730

You could also parallel the secondaries with the Antek to make a full wave bridge cap input design, good for ~425Vdc@410ma.

http://tubes.nekhbet.com/power.html#fulb

[glen]

That's perfect saved me some dough, thankyou.

[kheper]

That's perfect saved me some dough, thankyou.

No problem. Toroids are cheaper, they run cooler than EIs and there is not EMI, if you need to stack them.