HIGH-END AMPLIFIERS
Sometimes this hi-fi reviewing lark is just a whole barrel of fun. A visiting McIntosh power combo is one of those times...
McIntosh’s two-box amp delivers all the power you could possible desire...
If you’re going to have a treat, we reckon you might as well have a big treat. And for a hi-fi fan, spending time with a McIntosh amplifier at this level — a few coins short of $36,500 the pair — is getting on for as big a treat as they come. Those who have attended Australian hi-fi shows and entered the rooms hosted by Synergy Audio-Visual will know the warm feeling of being confronted by several racks’ worth of green McIntosh logos and glowing teal VU meters (many call them blue; McIntosh specifies teal — so they’re teal, OK?).
But of course, it’s the sound that is the thing. Just as everyone knows what a Harley-Davidson engine sounds like, McIntosh amplifiers have a sound quality that’s of similar renown in the audio world. But unlike Harley-Davidson, which rather extraordinarily managed to get a patent on its ‘sound’, McIntosh hasn’t managed to trademark its classic ‘valve’ sound’. Those teal meters, however, are definitely covered!
The thing with McIntosh is that it has maintained its amplifier ‘sound’ even with solidstate designs. The secret is in what the company calls autoformers. McIntosh decided that since it was using transformers in the output stages of its valve amplifiers, it would use very similar devices — the autoformers — in the output stages of its transistor amplifiers. Although these are quite different in design, their theory of operation is essentially the same and they ‘look’ exactly the same (electronically speaking) to any loudspeaker that is connected to one. And while the power output of a solid-state amp will vary depending on the impedance of the speakers you connect to it, the power output of an amplifier with an autoformer will remain the same, irrespective of impedance, or of the frequency at which the power is delivered.
McIntosh also uses its autoformer for another purpose, which is to combine the outputs of the four amplifiers inside the MC462 into two channels. Yes, four. Because unlike most stereo power amplifiers which, unsurprisingly, have one amplifier for each channel, the McIntosh MC462 has two amplifiers per channel, each pair operating in balanced differential mode, which McIntosh calls ‘quad balanced’. Advantages include higher power output, immunity to noise, increased dynamic range, and lower distortion. All good!
Equipment
So, here we are enjoying a preamplifier and stereo power amplifier combo — the C53 and MC462 respectively. Starting at the beginning, with the preamp, its front panel is bustling with controls, and at first glance you might guess the main row (shown above) were for input selection, but no, the large rotary control to the left of all those selects your input choice, of which there are plenty — three balanced inputs (via XLR), four unbalanced inputs (via RCA), two phono inputs (moving coil and moving magnet), and seven digital inputs (two optical, two coaxial, HDMI with ARC, USB-B for computer, and MCT, this last McIntosh’s own DIN-like connector which allows digital SACD/DSD signals to be transmitted in the purest quality, though they can only ever be decoded by a McIntosh DAC). There’s also a wealth of control, trigger and data inputs available.
The digital circuitry for the C53 is all contained within a single module (DAC2) which is able to be upgraded by switching in a totally new module, come the day that some
new digital format is developed or if McIntosh decides to add a new capability, such as MQA — at least one that can’t be addressed by a firmware upgrade. This makes the C53 essentially futureproof in this regard.
So we digress — what are all those frontpanel knobs, then? They are an old-fashioned multi-band equaliser, implemented via the equally old-fashioned method of a separate physical rotary control for each band, of which there are eight on the C53, with centre frequencies at 25Hz, 50Hz, 100Hz, 200Hz, 400Hz, 1kHz, 2.5kHz and 10kHz.
The rotary control to the right of the equaliser controls is primarily for adjusting volume level, but it’s also used for what McIntosh calls ‘Trim Selection’ operations, where you can adjust the gain for every input so that the volume doesn’t leap up when you switch from one source to another which has a higher inherent level (or lower, of course, though that’s less alarming). In fact the C53 allows you to do much more than that — you can also set channel balance, equaliser mode and mono/stereo mode for each input, and correct loads for each phono inputs to suit the specific phono cartridge connected.
The front panel hosts a full-size headphone output, designed to drive even difficult headphones, and has McIntosh’s ‘HXD’ (Headphone Crossfeed Director), feeding some information from the left channel to the right and vice versa, the idea being to reduce the artificial ‘in-yourhead’ effect that can affect headphone sound.
The front panel of the McIntosh MC462, meanwhile, is far cleaner, dominated by its teal power meters, which are calibrated from 4.5mW to 450W, with smaller markings labelled 900W and 1.8kW. The meters are also calibrated in dB, with -50dB coinciding with the 4.5mW calibration and 0dB with the 450W calibration.
The left-most knob on the front panel controls operation of the meters — ‘Off’, ‘fast’ mode showing the exact power, ‘Watts’ mode which switches the meter lighting on, or ‘Hold’ mode, where the needle ‘locks’ to the highest power output measured until a higher power output is detected. If the same or a higher level isn’t detected after a few milliseconds, the needles fall to the next lowest peak or, if no output is detected, back to 0dB. The decay rate is approximately 6dB per minute. The right-most knob is a three-position power switch.
And in terms of circuits, the MC462 is more than just its autoformer output and quad-balanced circuitry. McIntosh has invented and patented many different circuits over the 70+ years it’s been in business, and you’ll find more than a few of them inside the MC462. Two important ones are ‘Power Guard’ and ‘Sentry Monitor’ (both terms trademarked by McIntosh). Power Guard detects when output transistors are approaching overload and automatically reduces the signal to a safe level. It’s a good safeguard. As for ‘Sentry Monitor’, that’s a circuit that most high-quality well-designed amplifiers have to monitor the current in the output stage and shut it down if it gets high enough to damage the output transistors.
Performance
Setting up this duo took quite some time, but only because we were enjoying ourselves renaming all the inputs and playing with those ‘Trim Selection’ menus. There are three speaker terminal pairs — 2-ohm, 4-ohm or 8-ohm — and while you really don’t have to worry too much about impedance-matching, because there’s no penalty for getting it wrong, you not might get the maximum power possible if you don’t get it right. Although McIntosh says (quite correctly) that the MC462 will deliver its rated 450W output “into any loudspeaker load”, that’s only true if you connect the loudspeakers to the correct terminals. Connect a pair of 8-ohm speakers to the 2-ohm terminals and you’ll only get around half the rated output.
If you know the minimum impedance of your speakers (many manufacturers now state this in their specs), use the tap closest to this figure. If you don’t know it, use the 4-ohm terminals until you are completely familiar with the sound, then try the 8-ohm terminals for a similar period, then switch back to the 4-ohm. If the 4-ohm tap sounded better, repeat the process against the 2-ohm terminals. See what fun good hi-fi can be!
So we expected to be impressed by how loudly music could go without distortion — we listen pretty loud and most amplifiers can clip a little on the peaks. But after living with this McIntosh combo for some time, what impressed us most was almost the opposite — how quietly we could listen without hearing any distortion whatsoever, and absolutely no background noise. This is essentially an amplifier that has no audible distortion and no audible noise at low to normal listening levels.
But yes, the performance is just as good when you’re running the C53/MC462 combo with the ‘pedal to the metal’. But you surely won’t hit that metal with any normal loudspeaker; we had the volume so high that we heard woofers poling from excessive cone travel before the McIntosh MC462’s needles were anywhere near the right side of their meters. You are never going to need more power than the McIntosh MC462 can deliver, irrespective of your loudspeakers’ sensitivity or impedance.
And what does this mean for sound quality? Everything you’d expect. Kick drums with impact and visceral ‘thump’ like you’ve never heard before; electric bass guitar with the attack and ‘stringiness’ that bass guitarists love… in fact, just great bass, period. No matter the music, whatever the level, there was no wooliness or looseness audible. It was all just taut, gutsy bass rendering the image of the instrument being reproduced, whether contrabassoon, cello, double-bass or kick drum. The intro to Christy Baron’s Tomorrow Never Knows not only offers superbly realistic low-frequencies, but also captures their interaction with the recording environment. With the C53/MC462 combo the superb sonics continued up through the midrange and into the high frequencies, sounding super-smooth and superbly balanced at all times, never letting the smoothness interfere with the ability to resolve detail and nuances you just will not hear with lesser amplifiers.
Listening to Herbie Hancock’s Round Midnight (leading a group that includes Dexter Gordon on saxophone), all the instruments were in tight focus and in an airy space within the wide and deep soundstage. Hancock’s piano not only sounds ‘large’ but was also completely accurate tonally; Dexter’s sax sound was also phenomenal. The sonic dynamism enabled by the McIntosh duo is incredible.
We played Tracy Chapman’s Give Me One Reason from her ‘New Beginnings’ album, and the McIntosh duo delivered the scalpel-like instrumental separation for which this track is famous, plus the incredible amount of detail that makes it a demo favourite. The McIntosh C53/MC462 combo was able to project her voice ahead of the speaker plane.
The highs? Sublime, with cymbals and bells beautifully rendered in fine detail and surrounded by an airy lightness. In Rickie Lee Jones’ classic Chuck E’s in Love the glorious shimmer of the cymbals and the air around the harmonics of the higher-pitched instruments is almost palpable.
The C53’s headphone output also drove a resident pair of HD 650s perfectly. As for McIntosh’s HXD circuit, while many people will enjoy the experience, we preferred it ‘au naturel’, despite the inherent aural drawbacks.
Conclusion
There are many amplifier manufacturers that have arrived in the high-end audio arena more recently, and some of those build products that approach the performance of this McIntosh C53/MC462 pre-power pair. But are those brands iconic? Do they have a proven track record in the audio business? Do they have those bouncing teal power needles? No they don’t. With the McIntosh C53 pre-amplifier/MC462 power amplifier combo, you can have it all.