Center tapped primary?

[Captain chunkulus]

Okay, so thinking about using this transformer for a tube preamp build. So, it has a groun on what looks like the primary side. Would I just connect that to the chassis since it is labeled  ground? Also, would that just become more or less the first star point for the power supply? Just trying to wrap my head around it. Thanks. 

[Williamblake]

The gnd on the primary is for safety and will only conduct if another winding is shorted to it so it will not really matter where you ground as long a you connect it well.

[Captain chunkulus]

Great thanks!

[Captain chunkulus]

Okay, just checking to see if one of you guys can give me some clarification on what I'm thinking. I don't want to wire this Transformer incorrectly. So what it looks like is for the primary to output u.s. voltage. it Goes black to Black red to red and then connect the black side to neutral, the red side to hot. Ground the purple wire. For the 150v dual secondary if I want 300v output I need to wire yellow to white. If I want 12.6 volts on the 2nd secondary wire I would wire green and brown. Next question  is by wiring the 6.3v taps for 12.6v, what happens to the 5v secondary? Will it still output 5v? Basically I'm running my 12ax7s on 12.6v and using 5v relays, that's why I'm asking. I hope these questions aren't stupid. Thanks guys. J

[PRR]

> I'm running my 12ax7s on 12.6v

Why? And how many?

6V 2A will support six 12AX7 (12 triodes!), hum less than running 12VAC in the chassis, and leave the other winding free for other loads.

[Captain chunkulus]

> I'm running my 12ax7s on 12.6v

Why? And how many?

6V 2A will support six 12AX7 (12 triodes!), hum less than running 12VAC in the chassis, and leave the other winding free for other loads.

The original transformer only had a 24v tap so I ran the tubes on 12v dc using a voltage regulator.  It was dead quiet. So that's the way the heaters are wired now. I could rewire for 6.3v and maybe I will but it would be easier for me to just send the tubes 12v. So that begs the earlier question about the transformer wiring.

[sluckey]

Next question  is by wiring the 6.3v taps for 12.6v, what happens to the 5v secondary? Will it still output 5v?

5V tap will still be 5V in reference to the "0" tap.

If I were doing this I'd forget about the 5V tap and just put a FWB and big filter cap on the 12.6VAC. That will give about 17.8VDC unloaded. Send that 17.8v thru a 12v regulator for the filaments. Send that same 17.8v thru a 5v regulator for the relay.

[Captain chunkulus]

Next question  is by wiring the 6.3v taps for 12.6v, what happens to the 5v secondary? Will it still output 5v?

5V tap will still be 5V in reference to the "0" tap.



If I were doing this I'd forget about the 5V tap and just put a FWB and big filter cap on the 12.6VAC. That will give about 17.8VDC unloaded. Send that 17.8v thru a 12v regulator for the filaments. Send that same 17.8v thru a 5v regulator for the relay.

Will the amps be a problem  for the voltage regulator? Looks like the transformer puts out about 2 amps or current. I think the voltage regulator  is only rated for 1amp at 30v.

Also, would someone confirm the wiring for me. For 120v primary red to red black to Black, purple to ground. for 300v secondary, yellow to white and for the 12.6v Brown and green with the  blue going to ground?

[sluckey]

Will the amps be a problem  for the voltage regulator? Looks like the transformer puts out about 2 amps or current. I think the voltage regulator  is only rated for 1amp at 30v.

How many and what kind of tubes?

Also, would someone confirm the wiring for me. For 120v primary red to red black to Black, purple to ground. for 300v secondary, yellow to white and for the 12.6v Brown and green with the  blue going to ground?

That's probably right. Takes only a few minutes to know for sure. Put it on the bench, temporarily make those connections, power up, and make measurements. Watch for smoke!