Hi Johnny,
One question :)
You said you Toroidy a transformer of 3000VA.
You tried to put him in charge?
I have used in the new project 2500 VA transformers from Toroidy.
At a bias of 3.6 A had a very strong mechanical noise.
I tried DC filter, snuber, CRCCC, CLCC, NTC60 - no good result.
I...