I had a VS110 for about 6 years, transformer would buzz non stop as you said. The sound actually came from the silver plate protecting the circuit board, but your fingers on it and it will stop buzzing (anyways mine did). Tried tightening the transformers but to no avail. If I still had it I would put Blu-Tack between that plate and the chassis.
It didn't affect performance though, BTW a very nice amp for the price.
It didn't affect performance though, BTW a very nice amp for the price.