Padraigh wrote:
I've been looking at building a few vacuum-tube based projects (just for
the heck of it...and maybe use a few of the tubes I have siting around!
) I have been able to acquire a few single-winding transformers, both
HV(175-250 V) and either 6 or 12 for heaters
Question: since I do not have the dual-voltage transformers in a single
package, when wiring them into the circuit, are the 117V primaries
wired in series? This SEEMS correct, but my suppositions have been wrong
before!

"Stupidty is the only universal capital crime; the sentence is death.
There is no appeal, and execution is
carried out automatically and without pity."
Robert A. Heinlein
"TIme Enough For Love"

I assume you mean using two transformers, one for the hv and one for the
heaters. You must wire the primaries in PARALLEL NOT series! If you
want to operate the thing on a 240v line then you need to get two
identical transformers, put the secondaries in parallel and the
primaries in series (total of 4 transformers in this case).