Thank you for sharing.
One remark which I think is unrelated, but related to the story itself anyway :
If you hear those clicks and pops from switching on/off consumers, you should have something else wrong. But hard to say where this can be. One source of that I have for you : the stereo itself. For example, detach a ground from an interlink and there you'll have it. Maybe not by guarantee, but by the experience I have myself with it (all coincidental). So :
In some earlier days of my music playback I worked a lot with detouring etc. grounds and I took the clicks for granted. Or I left off the light dimmers and such. Well, you know.
In my current system, at one day, I suddenly suffered from the same; This goes so unnoticed (so to speak) that you take it for granted (again). It sort of belongs to the job (never mind that it was away for 10 years). But this time I found a bad soldering in a connection ...
Very similar happens with poor solderings in again interlinks. Why interlinks ? because we tend to solder on them ). So no matter how hard you try, things start to buzz and hum when not layed out carefully (like routing them over a PC is not careful).
If I now ask Ciska to solder an interlink, the problems suddenly stay away and the interlinks are allowed to route through everything.
Side note : remember those 3 organs I have ? one of them I built myself. A year of soldering ... But including my further soldering experiences, apparently not enough to do it really well. Ciska is just better at it ...
Of course we (you and me) are quite challenging with our 118dB sensitivity horns always at full gain. But, good thing, because at least we can hear it when something is wrong (to some degree).
Anyway moral : if I were you I'd find the source of the clicks and when solved go back to the trafo setup.