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conrad-johnson Classic 62SE and Classic 120SE power amplifiers

conrad-johnson Classic 62SE and Classic 120SE power amplifiers

Everything changes – everything stays the same. In a world where audio technology is shifting faster than most of the traditional high-end producers can keep up, or those producers are shifting faster than perhaps they should in an (often vain) effort to keep up, there’s something reassuring about these conrad-johnson amplifiers. In a market where well-established brand identities and product formats are daily being sacrificed to the twin gods of CNC machining and ‘visuals’, there’s something almost quaint about products that are more than just instantly recognisable – outwardly they’ve barely changed in the last 10 or 15 years. Oh sure, they’ve changed in detail, but even allowing for the full-height front-panel and rack handles on the MV45 (c-j’s original ‘everyman’ amplifier) the latest additions to the Virginian company’s extended family seem little different to their spiritual forebears from three decades ago: The same gold front panel; the same crackle black chassis; the same slotted tube cage and the same simple but effective hardware; all are deep in the DNA of c-j amplifiers.

Of course, if it ain’t broke don’t fix it and c-j amps have enjoyed a stellar reputation for their unfussy musicality down the years. Seasoned c-j watchers will be quick to point out the differences here, but they should also point out what is both the brand’s hallmark and its greatest strength: the painstakingly incremental, evolutionary approach it brings to product development. So the surface detail might change (component or tube types) but the underlying structure (topology, hardware, and construction) stay pretty much the same. If you’ve used a c-j amp before then nothing here will surprise you, from the simple fixed bias arrangement with its accessible trim-pots and LED tell-tales, to the basic appearance of the socketry and the absence of all but the necessary connections: no balanced inputs, no multiple output taps, and (thankfully) no ultra-linear/triode switching.

What you have here is essentially one amplifier writ two (in fact, four) different ways. The Classic 62 (£4,895) is about as simple as an ultra-linear tube amp gets, bringing all the traditional virtues – including its ‘traditional’ EL34 output tubes – to the musical party. Small enough to accommodate, powerful enough to run real speakers, it’s no surprise that the combination of dynamic and rhythmic integrity with the sense of colour and presence the topology delivers have made the push-pull, stereo chassis a staple in the UK market. Even so, there are situations where 60 Watts just won’t actually cut it – for which c-j, in time honoured fashion, have added a second pair of output tubes per side to create the Classic 120 (£8,995). So far so good and also, so very familiar: Where c-j deviates from the norm is in their development of refined versions of each basic design. Witness the TEA 2 phono-stage, available in no-fewer than three outwardly identical versions, each sporting identical circuit topologies, but separated by the choice and quality of the components used, the performance delivered, and the price asked. This ability to apply the experience gained with esoteric componentry and the knowledge of how it works in concert, to wring the subtle, incremental, but musically all-important benefits from an existing circuit has become the c-j party piece. The clearly defined musical and sonic performance benefits that attend each level of componentry when applied to the TEA 2 is both impressive and brooks no argument, the SE and MAX variations more than justifying their elevated costs.

Which brings us back to these current, Classic amps – and the decision to jump straight to the SE versions. Experience shows that, as practical and effective as the standard models are, the SEs bring that special something to proceedings. They also bring a scattering of c-j’s proprietary Teflon capacitors, deployed at strategic points throughout the circuit and a change of output tube, from EL34 to KT120. In theory, the bigger bottles should (could) provide more power, although c-j rate both the standard and SE models the same. It should also be noted that this is no straight swap, as the KT120 demands significantly higher supply voltages and draws a lot more current. However, what the switch to the KT120 does deliver is more headroom and greater control at frequency extremes. The EL34, long-loved for its glorious mid-band is beginning to show its age when confronted with modern, wide bandwidth loudspeakers – of which more later.

 

Hook up the Classic 62SE and the sound is as familiar as the amp’s appearance. Connection couldn’t be simpler, with the sole complication being the need for an unusually long and slender flat-bladed screwdriver to release the tube-cage in order to install the valves. That aside, with the amp biased and warmed through, you’ll be ready to enjoy some classic c-j sound. As I’ve already suggested, ultra-linear tube amps deliver a winning musical combination of musical presence and well-directed power that belies their rated output, leading to the old ‘tube-Watts-versus-solid-state-Watts’ argument. In truth, a Watt is, de facto, a Watt – but the vacuum-tube’s ability to deliver voltage means that it seems to achieve more with its Watts than its silicon-infested brethren. The Classic 62 is no exception to this rule, with an immediately pleasing sense of musical body, pace, and life. But c-j also bring their own special sauce to the standard ultra-linear recipe, adding a healthy dollop of tonal sophistication, harmonic development, instrumental texture, and a well-developed sense of acoustic space.

Like I said, everything’s different – everything stays the same, with the Classic 62SE instantly recognisable as a c-j amp, yet adding its own extension to the established set of musical attributes. With more focus, transparency, texture, and attack, the 62SE sounds like a grown up Classic 60, with more confidence and a firmer tread. It’s an impressive performer at the price – but it is also an amp that majors on subtlety and finesse, qualities that demand careful matching if you are to reveal and enjoy their full extent. What that comes down to is the matching speakers and as I suggested earlier, the difference between apparent and actual power. For all its presence and solidity, you’ll hear this amp at its best when partnered with the less complex loads generally delivered by two-way speakers. It’s not a question of efficiency so much as load characteristics – which is where three-way designs can start to cause concern. Paired with speakers as diverse as the diminutive Spendor D1 and the floor-standing Living Voice OBX RW3, the Classic 62 shone, leavening the infectious musical enthusiasm that marks out its parent topology with a subtlety and grace that made musical phrasing and rhythmic complexities effortlessly explicit, vocal communication intimate and expressive. The combination with the lucid precision and articulation of the D1 was especially impressive, with smaller scale acoustic music, be it Janis Ian or the Janacek String Quartet No. 2, Miles or Mozart, having a beguiling and involving quality that made for long and leisurely listening sessions (perhaps in this context it should be noted that the 62SE is factory set for 4 or 8 Ohm loads, but can be special ordered for 16 Ohm loads – ideal for all you LS3/5a users out there). But, where you can trip up the 62SE is if you step outside its power delivery comfort zone. Asked to drive the larger, three-way Spendor D9, it lost that breezy, confident quality, starting instead to sound small, clumsy, and muddled. Which is where the 120SE comes in – and where things start to get really interesting.

The Classic 120SE has a deeper footprint than the 62SE, to accommodate the extra output tubes. It also looks quite a bit prettier, with more pleasing overall proportions, the line of transformers along the rear of the chassis being boxed in to match the height of the tube-cage. You even get a set of c-j’s tube-dampers to fit to the 6922 voltage gain and phase splitter valves: a small but worthwhile touch. Where you’ll really notice the difference, however, is when you pick it up. The 62SE weighs in at a comfortably manageable 20kgs: its bigger brother nearly doubles that, at a grunt-inducing 35kgs, most of which is to be found in the larger output transformers and crucially, the larger mains transformer demanded by the additional wallop on offer. Hook this bigger beast up to the D9s and suddenly the speakers sit up and take notice. The 120SE gets hold of the bottom end, pushing it way down, keeping it under control, and investing it with the sort of pace, timing, and texture that doesn’t just bring a sense of musical purpose, it opens out the midrange and the system’s expressive range too. Playing the Janacek Quartet [from Quatuor Voce’s recent recording, Lettres Intimes, Alpha Classics 268], the 120SE/D9 combination reveals the dynamic tension in the playing, the almost erotic emotional intensity that characterises the piece. Along with the added sense of space, scale, and separation, the solid body and harmonic complexity of the cello, the easy separation of the smaller instruments, comes a greater sense of the poise as well as the verve, energy, and sheer vigour in the playing of this youthful quartet.

Change up to the other end of the orchestral scale and there’s a satisfying sense of detonation to the bombastic crescendos in the Johanos/Dallas Rachmaninoff Symphonic Dances, but here mixed with considerable subtlety and definition in the structural layering of the dense orchestration. The characteristic tonality of the Sibelius symphonies is beautifully captured, dark, sparse, brooding, yet alluring all at once, while the sheer presence and attitude this amp brings to rock and pop playing and vocals encourages you to advance the volume control, safe in the knowledge that with headroom to spare the sound won’t harden or glare. But what’s really impressive is that change back down, not to smaller scale music, but smaller speakers and the 120SE loses none of its subtle articulation, intimacy, or agility, while it still speaks with a voice of considerable musical authority, an object lesson in the musical application of available power, rather than the application of available musical power. Big amps that can still sound small, that can combine the control and grip that comes with ample power while still retaining the intimacy and deft agility of smaller amps are few and far between, and the c-j Classic 120SE is one of that rare breed. It’s a quality to be cherished.

Of course, the step up to the 120SE comes at a price (£10,995 as opposed to £6,495 for the 62SE), a price that places the c-j amp pretty much face to face with the critic’s favourite Audio Research Ref 75SE. It’s not a comparison that, in my opinion, the conrad-johnson amp needs to fear, as its sense of musical purpose and authority, its dynamic agility, and control and musically expressive character have far more in common with the large but also topologically similar Ref 150SE, an amp that I’ve spent considerable time with. The ARC scores in terms of scale and sheer weight, load tolerance, and its expansive stage, but transparency, texture, tonal differentiation, and musical insight are all firmly in the c-j’s favour, with its more compact but also more clearly defined soundstage and the temporal sophistication it brings to the music.

 

This pair of c-j SE amplifiers is a welcome addition to the range of options on offer. Sensibly matched, the 62SE offers superbly musical results for the price, while the pairing of this amp with stable-mate Vienna Acoustics’ exquisite Haydn is an enticing proposition. But if you can afford the step up to the Classic 120SE then the results and benefits are quietly spectacular. Not an amp to shout about itself, but one that stands firmly behind the music: it has the grip and control to handle speakers as demanding as Vienna’s impressive Liszt, while having the subtle intimacy, poise, and communicative grace to bring recorded performances to life. Things may have changed, but at least one thing is still very much the same – conrad-johnson still builds seriously impressive and musical power amps.

TECHNICAL SPECIFICATIONS

Classic 62SE

Type: Ultra-linear tube power amp

Valve Complement: 3× 6922, 4× KT120

Input Impedance: 100 kOhms

Rated Output: 60 Watts/ch into 4 Ohms
Can be special ordered for 16 Ohm loads

Dimensions (W×H×D): 440 × 168 × 340mm

Weight: 20kg

Price: £6,495

Classic 120SE

Type: Ultra-linear tube power amp

Valve Complement: 3× 6922, 8× KT120

Input Impedance: 100 kOhms

Rated Output: 120 Watts/ch into 4 Ohms
Can be special ordered for 8 or 16 Ohm loads

Dimensions (W×H×D): 482 × 194 × 480mm

Weight: 35kg

Price: £10,995

Manufactured by: conrad johnson design inc.

URL: www.conradjohnson.com

UK Distributor: Audiofreaks

Tel: +44 (0) 20 8948 4153

Net: www.audiofreaks.co.uk 

Tags: FEATURED

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