Like may Circle members I have been on a lifelong search for the perfect amp (at least to my tastes) and have owned at least 6 or 7 amps in the last 5 years - including Shindo, First Watt, Music Reference, Carver, a custom 2A3, a custom F2, and more...you get the picture. A while back I purchased a pristine Conrad Johnson MV75a - bought it from the original owner who had had it maintained by a tube place in Seattle. Having purchased a new CJMV45a-1 back in the day, I bought it more as a collector piece than with an intention to use it heavily. I love this amp, played through both a Spatial Audio M3TM and Daedalus Custom Studio spkrs. It brings an ease to the music, a flow if you will, that I seldom find in amps. No claim that this is the last amp for me (although at age 72 it might well be) but I have to ask what the heck have amp designers learned in the 40 years since this MV75 was designed?
Well, maybe because of after 40 years of breaking in now is sound good?
I'm not an amp designer or electrical engineer but I'm a DIYer and I've built and tinker with audio for sometime now. I think tube amp technology haven't change much the past 40 years, what changed are parts. I have two SET amps, one pair that I've been using since 1999. SET design have been around since the dawn of audio. Sound great to me!
What I have noticed is that older tube amps can sound mellow and this can make it sound what you could call "sweet" and this works well with many recordings that are bright sounding.
I've changed parts before to get "more" and only ruined the beauty of the original sound.
I know what you mean, lesson learned the hard way. And that's why I stop doing that.