Go to psaudio.com as they have a section on transformer buz! very interesting article! Happy Listening!
Buzzzzzing Transformers
My solid state monoblock transformers buzz. I use a CJ tubed preamp (PV9a) and a modified TNT Turntable. I use an SDS for motor stability and a PS audio 300 power conditioner which I set in to the very basic mode without upping the frequency. Could this conditioner be the source of the problem?