Advise Needed - 2 Power Transformers in 1 unit, Hookup & Grounding??

I need to add additional +/- rails to an existing tube power supply that already has 120v (B+) & 12v (Heater)...
it's basically the PRR Vari-Mu PSU.

I tried hooking up a second transformer to the Main (AC) for the +/- 17v supply but things got screwed up & even after unhooking the second TX,  the original supply has a lot of noise EVERYWHERE... even the Ground (measured on my scope) that wasn't there before trying this.

I'm not sure what the "Rules" are when it comes to using 2 separate TX's in one unit & how the Ground &/or Center taps should or shouldn't be connected?

Is it even possible or should it be avoided?

I was considering building a NEW PS similar to the G9 Mic pre, that hooks the second TX backwards to generate the B+ (120v:17v > 17v:120v) but I'm not sure how to correctly connect the Grounds or Center taps?

I'd appreciate any help or advise I can get.

Thanks

Should not be a major problem.
Hook up the second to the same mains AC lines / fuses, perhaps put a few inches of space between them in the case.
Don't "stack 'em" maybe you need to fiddle a bit with position and distance between them, otherwise it's a no brainer.

Don't know how they are interfering with one another ... how exactly are they wired / placed ??

MM.

Well I do have them pretty close..here's a quick shot:

That looks a bit close to me, how about take it to the right side of that board, that's a few inches further away.

The "bread board" circuit section might not be helping with your noise and ground issues either !!

Are both traffo's coming onto the PSU board with specific designations for the +17/0/-17 vac and your
original ac points for this build ....PCB or VERO? or are you adding a new PSU section ?

Grounds = star ground .... all good ??

IMO a tidy up of the breadboard and better space between traffo's should help.

MM.