monarchy audio SM70 pro

Hello:

This is an amp I''m interested in.
SM-70
I do understand that Mr. C.C. Poon-the designer- does use local feed-backs, but no global.
It is described as fully class A and fully balanced when the XLR connector is used in mono mode.
However, despite the very favorable listening or sonic performance reviews, an issue of hum has always surfaced and the designer always suggests to use cheater plug to remedy the issue.
The upgraded system makes use of new low noise rectifiers from D6SB601 from Shindengen. There is an article from a 3rd party to improve the mod found under technical notes Sm70/sm70 Pro low noise rectifier upgrade.