Is it possible for you to characterise your experience with the Atma amps before, during (break-in) and after when the sound finally settled?
Thank you Tom.
I found the amps and preamp more similar than different across break-in. Out of the box there was plenty of resolution, but the sound was a little tight and closed-in. Relatively speaking, tonality had a wee bit of a greyish cast. During break-in, which I counted roughly at 120 hrs for the preamp, and a little more for the MA-1s, music gradually became relaxed and seemed to flow with a more natural pace. Tonal colors made something of a transformation towards the end of the break-in period - they really blossomed - all of which was rather startling. That final leap came over a few days for the preamp, and, say, over a weeks time for the MA-1.
The subsequent addition of the V-Caps to the MP-1 took things back a step before going forward two. Highs and the mid-bass got a tad edgy and a touch of the greyish tonality returned. Over roughly 6 weeks, things smoothed out and the tonal colors deepened. Sonic memory is difficult, but I'm confident that tonality eventually improved beyond where things had got to prior to the V-Cap upgrade.
Fwiw, I find both amps and preamp sound their best after being on for 1-2 hours - the hotter their tubes the better.
Tim