Belles Power Modules 20A pre. Whos heard one?

I know from personal experience that the Belles 150A Hot-Rod is one of the best values in a solid-state amp available, he now has a tube hybrid preamp called the 20A which employs 4 / 12AU7s from EH as stock.

Two questions here:

1.) Has anybody heard the pre and if so, your audio-thoughts?

2.) What tube could replace the Electro-Harmonix 12AU7 that would really give the pre, or ANY pre, a real sonic advantage?

thanks, Audiojudge
The 20A is not a "hybrid" preamp - it is a pure tube design. It is excellent for the money, and includes remote volume and mute. It also has a full record loop (which can be monitoring a different source than the listener) and a home theater bypass. I think this is another classic Dave Belles design with great sound and cosmetics. It has been pretty popular for us.

Personally I think that the EH tubes are very good, but there are probably people here who will recommend all sorts of NOS replacements.
Thanks for the insight. I always appreciate an answer more sincerely when the responder has actually has some "interaction " with the said product in query.

Can you tell mw what you might be putting it up against. Frome my personal experiences, I would put it up against some things at 40% - 70% the monies and still hold it's own.

I own one ... excellent value / great sound.
Allows me to use it in my HT set-up and run pure stereo / hybrid HT or 100% HT as I wish.