Classé CT-M600 & CA-M600 monoblock power amplifiers Page 2
A large toroidal transformer behind the front panel supplies power to three stacked printed-circuit boards behind the transformer. The bottom two boards carry multiple storage capacitors, the top board the relay and housekeeping circuitry. All the audio circuitry, including the 36 output devices, is carried on two six-layer boards mounted either side of the fan tunnel. This allows signal paths to be very short, minimizing any parasitic effects and keeping the amplifier's noise floor very low. The circuit is new rather than developed from earlier Classé designs. Both balanced and unbalanced inputs are provided, but Classé warns that operation from the unbalanced RCA jack is not quite as immune from RF interference as from the balanced XLR. (If the RCA input is used, a jumper needs to be inserted between pins 1 and 3 of the XLR, to tie half of the balanced circuit to ground.) There are two pairs of shrouded speaker terminals to allow easy biwiring, and the amplifier offers a full array of trigger inputs and outputs, Classé's own CAN-Bus control protocol, and IR Remote repeaters, as well as USB and RS-232 ports.
Classé provided me with two sets of accessory feet ($140) to use with the CT-M600s, which use Navcom inserts to provide isolation from vibration.
Several months after I had received the CT-M600s, Classé sent me a pair of CA-M600s. This is the same amplifier, but packaged in Classé's traditional Delta-series enclosure, with its brushed-aluminum front panel curved round to form the side panels. The fan pulls in air from a square slot concealed on the black front-panel insert. I studied both models with their vibration-damped tops removed; under the skin, the two appeared identical, the only apparent difference being the orientation of the toroidal transformer: vertical in the CT-M600, on its side in the 100mm-taller CA-M600. The more domestically acceptable styling of the CA-M600 adds $1000 to the price of a brace of amps.
I used first the CT-M600s, then the CA-M600s, for a total of nine months. In that time I used the amplifiers with a wide variety of loudspeakers, from the current-hungry Focal Maestro Utopia IIIs (reviewed in July 2010), the miniature and exquisite Harbeth P3ESRs (reviewed in August 2010), to the supersensitive, horn-loaded Acapella High Violoncello IIs (reviewed in September 2010) and the weird and wonderful Gradient Helsinki 1.5 dipoles (reviewed in November 2010). Following the return of the Gradients, I returned to the Harbeths to review some digital source components. In all that time, I never felt I had a handle on the sound of the Classé amplifiers.
And as I prepare to send this review off for copyediting, I still don't. In either of its guises, the 'M600 is the consummate chameleon.
Yes, I could draw comparisons with other high-performance amplifiers. The Parasound Halo JC 1 monoblock, for example, sounded more intense in the treble. But that doesn't mean the Classé sounded dull. Far from it. Yes, it had a firmer grip on the Focal's big woofers than did the Simaudio Moon Evolution W-7, but that doesn't mean it sounded lean. Far from it. Yes, I enthused about the transparency of the NAD M2 Direct Digital amplifier (reviewed in March 2010) fed straight digital data via S/PDIF. But that doesn't mean the 'M600s didn't sound transparent. Far from it. Yes, one reason I had bought the No.33Hes was the enormous soundstage they threw, but that doesn't mean the Classés' soundstage was any less expansive than my memory of the Levinsons'. Far from it.
Whatever speakers I used with the Classé monoblocks, each pair of speakers sounded more like themselves than they did with other good amplifiers. Whatever recordings I played through the 'M600s sounded more like themselves. With both speakers and recordings, it was if the colors in the sonic picture were more intensely saturated. The amplifiers' deathly quiet level of background noise allowed them to step out of the way of musical details that I have rarely experienced from electronics. Their enormous dynamic range allowed musical climaxes to be reproduced in full measure, even with modest speakers that you'd think would be overtaxed.
As I finish writing this review, the CA-M600s are driving the Harbeth P3ESRs. The front-end is the dCS Debussy processor taking USB data from my Mac mini running PureMusic with AudioQuest's new Coffee cable. There's no preamp in the system. I'm using the Debussy's own volume control, with balanced AudioQuest Wild cables feeding the amplifiers and AudioQuest Wild speaker cables hooking up the Harbeths. Paul Simon is singing "Hearts and Bones," ripped in Apple Lossless from Negotiations & Love Songs (CD, Warner Bros. 25789-2). It is hard to believe the hi-fi experience can get any better than this. I know that's not the way the world is, baby, but at this moment, it is all I need.
There seems to be a feeling in some quarters of audiophilia that to get state-of-the-art amplifier sound and performance, you need to pay many tens of thousands of dollars for a product made in tiny numbers from an equally tiny company. By contrast, the Classé CT-M600 and CA-M600 come from a mainstream manufacturer, though they are still expensive amplifiers. But they are nowhere near as expensive as the artisanal models, and they are the best-sounding amplifiers I have auditioned in my system. It is going to be difficult to let them go. Maybe I won't.