Sneak Peek: A Pair of Heavenly Integrated Amps

Posted by: Neil Gader at 9:09 am, February 6th, 2009

I’ve been listening to an exceptional pair of integrated amplifiers over the last few months and I thought I’d share a couple early impressions. The Marantz PM-11S2 and the ATC SIA2-150 are not small units. They are high power components, capable of shouldering aside even the toughest speaker loads. They are designed as a viable alternative to separates. And their performance seems to back this up. Not since the Pass Labs INT-150 have I heard this kind of robust dynamic output married to such delicate resolving power.
First things first, the Marantz ($4495) and the ATC ($6500) couldn’t be more different at first glance. The Marantz  is a classic updating of their reference line with champagne finished metal work and a  full copper chassis. The illuminated center dial indicates the input and volume while the side knobs control volume and input. Two rows of vertical buttons are illuminated in a soft blue. The whole effect is glorious, like a glowing tribute to amplifiers past and present.  The PM-11S2 is  also biampable, designed to be paired with a second PM and includes a MM/MC phono stage (the ATC does not) and enough power supply and capacitance to bump its weight up over 58 lbs. Power is a very conservative 100Wpc into 8 ohms which doubles into 4 ohms.


ATC, as many know is maker of professional active loudspeakers but they also have a more audiophile friendly “passive” line that can be paired with their own compatible electronics.  The SIA2-150 is a 150Wpc unit that’s based in large part on the topography of the amp-packs that are slipped into their active monitors. They are fairly warm running in operation with a goodly amount of Class A bias. The look of the SIA2-150 is pure Art Deco and reflects ATC founder Billy Woodman’s fondness for the visual appeal of vintage auto dashboards and studio electronics  of decades gone-by. I think it’s a very smart and distinctive look that should please many audiophiles tired of the bland, tech look of much of the gear that’s currently available.

Sonically each amp immediately establishes itself from the bottom of the soundstage on up. When a piece of music begins you can feel the acoustic space load-up with low frequency energy even prior to the first note being struck. The hall or venue itself becomes a silent presence in the listening room. Only amplifiers with deep reserves of power and control seem to consistently have this distinction. Both amps are neutral but not rigidly so. That is they both have a character and it’s a darker, warmth factor that veers away from the clinical or dry. Tonally the ATC is slightly fuller in presentation and offers a more rounded, continuous and complete soundstage effect. The Marantz seems to run as deep in the bass but its decay characteristics are not as extended in duration. The Marantz is very present in the mids and upper mids and has a glow or sheen in these regions that emphasize the beauty of strings and female vocals. It’s almost as if a couple output tubes had somehow slipped aboard that gorgeous copper chassis. Both amps enlarge and enliven the soundstage.  I still have some questions regarding the amount of air and the quality of treble extension they impart. They are different in this regard. Both very good but perhaps not quite a match for the Pass Labs. The full review of each amp will be published this spring. For the moment I’ve still got some more serious listening to do.