Tubes Asylum: REVIEW: Atma-Sphere M60 MKII Amplifier (Tube) by Dan

This amplifier is a fully differential circlotron output transformer
less design with 6AS7 output tubes. Drive is 6SN7 utilizing a
phase splitter, cascode and cathode follower. I've owned this amp for
about a year now and have heavily tweaked it so feel like I understand
it pretty well. For furthur information go to the users group

http://www.condor-connection.org/asog

If you like detail this is the amp for you. Details galore, but not
analytical. Its got a relaxed warmth, an ease that encourages listening
to the music, and not the equipment. In fact, you really can't
listen to the amp it impresses so little of itself on the music. My
inital thought hearing it was that it was an amp that I couldn't hear,
and I still believe that. No output transformer to influence the sound,
just all triode electronics. Frequency extension from a few hertz to
200 kilohertz! This is the one of the fastest, most detailed amps you
will ever audition. The kit is a steal for $2400 only requiring modest
soldering skills and a DVM.

I listen to only classical and opera, to date this is the only amp
that can do large scale works to my satisfaction. From what I've heard
large operatic/orchestral works are the most taxing on a system, most
likely to show up problems, and this handles all the complexity of an
orchestra, soloists, chorus with aplomb and ease. In many other amps
I've heard errors seem to compound with these kinds of works until
they become painfully obvious. Here all the glory of the original easily
comes out.

Back in the music conservatory my teachers taught me to play with
a "full", not "loud" tone. Anybody can play loud, but only an artist
can play with such a full sound as to rivet everybody in a concert
hall while playing triple-piano. This amp seems to believe this also.
Some have said that it slightly leans towards a dark sound, my ears
hear it doing that full tone thing, probably one of the reasons I fell
in love with it.

Stock they are great, tweaked they are heavenly. If your preamp
has enough gain drop the cascode. Add output capacitance, get better
input tubes and output tubes and many other tweaks and you will have
a large, clear, detailed, full and round warm tone that is an
absolute joy. I would go as far to say you haven't heard this design
unless you've heard a fully tweaked version.

Now for other genere's such as rock (others will disagree
with me here) I think you might be best served by another amp. If
you want ground shaking bass this amp is one of the few that will
give you the frequency extension, but it needs tweaking or upgrading
to a MA-1 to really shake the walls. My wife complains that its
much too clear for her rock music. For my chamber music, lieder
and such I *sometimes* think a high quality SET might lend an
nicer intimacy. Also old jazz (Duke Ellington) and historical
performances (Fritz Kreisler, Knappertsbusch, Flagstad/Tristan
und Isolde) don't seemed to be served well. The amp just painfully
details their shortcomings, instead of letting you enjoy the gems that
are in the performance.

But if you have source that is up to the task, and especially if you
listen to larger works I believe this is the pinnacle. Buy it, built it
and enjoy.

REVIEW: Atma-Sphere M60 MKII Amplifier (Tube) Review by Dan at Audio Asylum