Transformer Wiring questions

[Pdavis68]

I have the transformer shown in the image below. This is from the PA it used to be in.

I'm now using this transformer in an amp I'm building and I don't recall the wiring exactly (I started this amp like 3 months ago and knew the wiring then, but have since forgotten it) and was hoping for help:

Green is the 6.3V filament, I know. Red goes to pins 1 and 7 of the EZ81.

Red & Yellow: Is that the HV CT?
Green & Yellow: Heater CT (appears to have been elevated in the PA, maybe)?

Also, the transformer has 2 wires for the incoming live: Orange and Red/Black. One is normal voltage and the other lowers the B+ (about 10%, I think). I don't plan on using the reduced power one, but I'm not sure which is which. Any ideas?

[Pdavis68]

Related question: The original PA had an EZ81 tube, as does this 18W lite build that I'm working on. Most of the wiring diagrams I've seen for EZ81s in 18W Lite builds has a separate 0-6.3V taps for the EZ81 filaments (instead of 6.3V CT for the rest of the tubes), but this PT doesn't have separate taps. They ran the filaments for the EZ81, as well as the rest of the tubes off of a single tap. Does that mean my filaments need to be grounded on one side?

[eschertron]

This data sheet ez81-philips1970 shows an indirectly heated cathode, so the heaters can be grounded according to whatever your standard scheme is. I opened up an old Harman-Kardon tube receiver just last week with an EZ-81 recto, and while there where two separate 6.3vac taps, the recto wasn't alone on its string; it shared heater power with some other tubes. I thought that was strange at the time. But it validates what you are doing with your heater string. Note that the heater current is a whopping 1A for the recto, I should probably be first in the string for that!

[Pdavis68]

This data sheet ez81-philips1970 shows an indirectly heated cathode, so the heaters can be grounded according to whatever your standard scheme is. I opened up an old Harman-Kardon tube receiver just last week with an EZ-81 recto, and while there where two separate 6.3vac taps, the recto wasn't alone on its string; it shared heater power with some other tubes. I thought that was strange at the time. But it validates what you are doing with your heater string. Note that the heater current is a whopping 1A for the recto, I should probably be first in the string for that!

Thanks. That validates my thinking.

Now that I look at my original question, I kind of answered the heater part myself. It doesn't have to be grounded and in fact, they elevated the heater center tap (assuming green/yellow is the heater CT, which I'm now virtually certain of) in the PA. So maybe I ought to do that here and tie the CT to the power tube cathodes...

My main concern was hum, so that should help there.

Yes, it's first in line, then power tubes, then preamp tubes.

So that means the red/yellow is the HV CT.

Black goes to Neutral?