Dan D'Agostino S250 and M400 upgrades

As many wanted to know what the Dan D'Agostino S250 and M400 upgrades brings sonically, here is a short impression by owned Ted N via Fidelis Home Music Systems:

"I have owned the stereo and mono amps for several years now...when I heard about the S250 and M400 upgrades I decided to send in the stereo first and hear the results prior to sending in the monos...when the S250 came back I couldn't believe the difference..it was obvious that this is not a minor update; rather, it is an upgrade equal to an entirely new amp...versus the original stereo amp we now have a dead quiet black background from which sound emanates and soundstage depth is limitless...gone is the forward sound of the original in favor of a now more relaxed presentation, but without any loss of the dynamics or bass slam that Dan is known for....the sweeter tonality and organic body of the S250 are dead on..in fact these are eerily tube like...overall, the S250's greatest accomplishment is its complete lack of listener fatigue...unlike the original, I can listen to this piece hour after hour after hour...I will definitely be sending in the monos for their M400 upgrades ASAP!!!"