CH Precision L10 line-stage preamplifier and M10 twin-chassis power amplifier

Solid-state power amplifiers,
Solid-state preamplifiers
CH Precision L10,
CH Precision M10

Given the popular belief in the law of diminishing returns, given the fact that the 1 Series have already established themselves as benchmark performers and given the outward similarities between the 10 Series and the more affordable 1 Series (please note the qualifier – I’m not sure anybody would describe the 1 Series as affordable!) I insisted on having the L1/X1 and M1.1 on hand for direct comparison. Such is CH’s confidence in the 10 Series that I also received not just the L1 and M1.1 but the full four-box line-stage and a pair of power amps. On the downside, that’s a lot of boxes and an awful lot of comparative listening. On the upside, it brings a whole new meaning to the phrase “ten tons of fun!”

So, was CH Precision’s confidence in the 10 Series well-founded? Sit the 1 Series alongside the new flagships, take a listen and it will take barely a note to appreciate not just the scale of the difference, but its musical significance too. There are two ways of looking at this: you can simply compare equivalent 1 and 10 Series set-ups – or, you can work up to the 10 Series, one product at a time. For owners of 1 Series, it’s probably those incremental steps that matter, so let’s start there and the obvious place is the L10. Dropping the flagship pre-amp into a system comprising the L1/X1 and a pair of M1.1s quickly demonstrated why CH sent me the four-box L1. The gulf in performance between the two-box 10 Series unit and its 1 Series equivalent was huge, with the sense of clarity, flow, transparency and human agency dramatically more apparent with the L10. Even stepping up to the four-box L1 only narrowed (rather than closed) the gap, the quartet of 1 Series boxes delivering their trademark solid stability, but unable to match the lucid articulation, transparency, ultra low noise floor and fluid musical expression of the L10. Using the Kertesz/VPO New World (Decca) as a benchmark, the L10 delivered a more musically emphatic performance, with more drama, more effective pacing and greater momentum. It wasn’t just that the orchestra sounded more energised, and their instruments were more vivid and natural. They simply sound more here, the sense of purpose and overall direction, the influence of the conductor on the shape and pace of the music far more obvious. Switching scale and genre, with Jackson Browne’s ‘The Road’ (Running On Empty) the L10 demonstrated more natural tonality and diction on vocals, a more expressive and intimate performance. The difference in height between the fiddle and the guitar was more obvious, but also made more sense, adding to the intimacy and putting you inside that hotel room. The mid-track shift to the concert venue extended the acoustic space out beyond the confines of the listening room. Despite the efforts of the engineer to fade from one location to the other, the actual switch was far more clearly defined, adding another layer of insight into the process itself, without pulling the track apart.

Putting that in perspective, in Issue 175 Alan Sircom  described the four-box L1 as “one of the finest pre-amps ever made” – and he wasn’t wrong. Not only that, but the four-box L1 actually costs more than a single, two-box L10. Yet in direct comparison, the L10 still succeeds in making the L1 in its ultimate form sound processed and constrained, gated and slightly clumsy! That isn’t to belittle the four-box L1, which remains one of the finest pre-amps we’ve heard. It’s just indicative of how far the L10 has raised the bar. Once you factor the M10 into the equation, the performance gap becomes a yawning chasm. The loudspeakers I used for this review were the Stenheim Alumine 5 Signature and Göbel Divin Noblesse, with and without the PureLow LO sub-woofers. You can bi-amp both speakers, an approach that makes the most of the CH Precision power amps’ configurable in and output topology. That means that, when comparing a pair of M1.1s to a single M10, the 1 Series amps should enjoy a significant advantage, being able to bi-amp as opposed to simply bi-wire the speakers. But despite that, the performance of the single M10 still trumps the pair of M1.1s, delivering greater separation and dimensionality, timbral and textural definition, fluid rhythmic expression and more positive dynamics, all set against a ghostly quiet, jet-black background. Instrumental identities in the opening bars of the New World were far more clearly defined and recognisable, the pacing more explicit, the steps on the staircase leading to the first big crescendo wider and far more clearly delineated in terms of dynamic range and density. The complex patterns and staccato rhythms of Kopatchinskaja/Gabetta’s Les Plaisirs Illuminés are more ordered and intelligible, the instruments more vibrant and the playing more incisive. Add the second M10 and you start to wonder how on earth you were so impressed with the M1.1s? Swap directly from the four-box L1 and a pair of M1.1s to the L10 and M10s and the difference is frankly astonishing. Raising the bar? This is like Sergei Bubka turning up to the 1924 Olympics. And therein lies the challenge. The L1 and M1.1 didn’t stop being great products overnight just because the L10 and M10 appeared. They are still great products. Appreciating the true extent of that performance gap depends on direct, side-by-side comparison – meaning that if you leave the 1 Series alone for a bit and then come back to it, you’ll find it’s recovered its composure – or you’ve forgotten its discomfort. But that doesn’t change the reality that in very real terms, the 10 Series represent a step-change in the performance envelope – a step change that becomes apparent as soon as you listen to them. They have forced me to reconsider the way I think about amplifiers and the way that they work.

In the past, reviewers have always tended to describe amps in terms of what they do: amplifier A has a massive soundstage, amplifier B has incredible detail, but amplifier C – just wait ‘til you hear its bass. It’s almost as if the amps are bringing out or extending attributes in the system’s performance. With the 10 Series, that gets turned on its head. Instead of marvelling at what they do, you suddenly realise what they don’t. Or to put it another way, you realise just how obvious the sticky fingerprints that other electronics smear across the signal really are. What makes the 10 Series special is that absence – the intrusion, the distortion, the compression, the additive colouration and the etching or thickening that they don’t impose on the signal or superimpose on the performance. The 1 Series has always been noted for its uncanny ability to offer low colouration without resorting to the sort of clipped sterility that so often passes for neutrality. But in terms of musical and operational invisibility, the 10 Series is simply in another league – which is exactly what you hear when you place them side-by-side. 

If you want to assess an amplifier or system’s ability to stand aside, the acid test is comparing different performances of the same piece. After all, it’s hard to confuse Isaac Stern and Lisa Batiashvili – musically or visually. But in audio terms you can take it a step further still, comparing different pressings or masterings of the same recording. Time and again, the musical distinctions between different pressings of the same, often familiar recording were laid bare: Du Pré’s Elgar Cello concerto in its original CD issue, the SACD, the UHQCD and the live performance on Testament; original and UHQCD issues of Coltrane’s My Favorite Things; Kleiber’s Beethoven 7th on DGG as opposed to his live performance on Orfeo. The list goes on, with one example of superior musical or recording integrity after another – with differences that varied between the interesting but academic and the shocking but exciting.

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