Relative phase of PT secondaries?

[vh junkie]

I had a 12xxx build that had a bit more hum than I would have liked. I went so far as to install a humdinger, and that did not help at all.
So I did two things:
Reversed the secondaries were they connected to bridge
AND
Replaced the 1n5408 bridge with UF5408

Now the hum is gone. Don't know which mod fixed it... I guess I could reverse the secondaries and find out; but, this got me to thinking... Is an amp likely to be quieter depending on the alignment of the phase in the secondaries (B+, bias, heaters)?

[Strat78]

Freds huh, Could it have been a bad diode?
Interesting about the secondaries. I'll keep this in mind.