April 2021

CH Precision — A Postscript Review
Three months after the dust settled on last issue's marathon project covering CH Precision's all analogue A1.5, P1, L1, X1 amplifier system (approximately £80,000 the set), some more aspects came to mind, says Martin Colloms.
Review By Martin Colloms

  While I was in the thick of considering the CH Precision A1.5, P1, L1 and X1 (HIFICRITIC Volume 14 Number 4 Oct - Dec 2020) late last year, such was the complexity and range of settings and modes and connections, and not least power supply options, that a considered overview was somehow just out of reach. Moreover, those continued and complex evaluations were inevitably constrained by particular circumstances in that more extended trial and error methods to establish quality limits could have added value, for example exchanging multiple cables in all positions, signal, and loudspeaker, and also mains connection methods, whether central or extended line. Then there is the matter of optimising the choices and subsequent alignment of anti-vibration frames and optional intermediary supports.

Looking back at the many pages of notes made during my extended listening tests, some extemporising now seems possible – and may add value to the review analysis. It seems clear to me that if the Covid-19 lockdown had been absent, I would have welcomed sharing the auditioning with colleagues. They would likely have assisted with suggestions and alternative trials and combinations, and I would have benefited from their opinions and hands-on support.

As conceived, the project planner, working remotely with Definitive Audio, made a particularly good stab at the overall proposition, seeking to deliver as much infrastructure as possible to embark on this massive system review. With equipment of this quality, reaching something close to optimum performance requires thought and meticulous attention to detail. For example, to reach peak performance from a high-end phono preamplifier / equaliser such as the CH P1, which processes microvolt signals from the pickup cartridge, it is all in the installation detail.

Here we have many factors which could blur and obstruct the qualities of focus, dynamics, and transparency in the reproduced soundstage. Such losses are frequently additive. As it happened multiple install details were addressed – though still more could have been trialled – with variables tested in various combinations including the power cables to the P1 unit and to the auxiliary X1 power supply, whether or not the X1 was used, and the physical support in use, including the Naim FRAIM triple-tier stands, and also those Grand Prix Audio Apex Feet vibration absorbers.

Not least among the considerations were the audio output cables to the L1 control unit, in both single ended and XLR balanced formats and also the make/brand and specific type. For the P1 we also have the options of current or voltage input feed, together with the complementary range of input settings, and finally source loadings and equalisations. Including confidence augmenting repeats, also with direct comparison with references, some fifty auditions were devoted to the CH P1 phono equaliser alone!

Recording The Journey
In this case first impressions were very promising leading to a serious commitment to evaluate in depth, not only to meet the intellectual challenge presented by its designers, but also to carefully record and rate the evolving and hopefully musically rewarding journey.

CH have become skilled in designing and building audio circuit blocks of almost open-ended performance, giving them the freedom to make audio products with inherent potential from their inception, but also allowing significant sound quality improvements when various installation aspects, and more frequently further funds, are applied.

Thus, the CH Precision P1, L1, X1, A1.5, product group can be seen as the core components of a system of audio component combinations capable of substantial and rewarding expansion. I will not muddy the waters with a discussion of their newest and still higher performance two-box Series 10 pre-power audio electronics, set well above the 1 series and with the two first two items in the line provisionally priced at €160,000 the pair.

But I see now that I have put the cart before the horse. I should have begun this discussion with the final elements in the chain and worked back since these are required deliver those controlled and amplified sounds into the listening space. To have a reasonable chance to evaluate system quality at this level loudspeaker choice is crucial. It should be of sufficient quality and optimally installed so as to allow audio critics to hear down the chain of electronics and cable harnesses right back to the phono cartridge. By the same consideration, a given powerful, musically revealing and transparent loudspeaker selected for the evaluations, here the Magico S5II with matched SPod vibration controlling supports, requires a calibrated installation of comparable quality in the listening space, including selected, equal length, anti-vibration supported high power cables running back to the power amplifier.

The Effect Of Cables
By a stroke of good fortune, at the time I had also embarked on the evaluation of some 14 interconnect, loudspeaker and power cables, and was thus able to employ the installed CH review system as a test-bed for the cables, and the cables to assess the audio electronics.

There have been debates concerning the choice of audio cables, whether mixed or single brands – or, within a brand, specific sets, or series within a cable range. It is possible that you can have too much of a good thing: a complete cable set, or loom – encompassing power, interconnect and loudspeaker cabling – may contribute a cumulative character stemming from the materials and technologies employed in the construction.

In the case of the CH system review, I had readily become acclimatised to the comprehensive Chord Sarum ST loom supplied with the review set-up, which delivered undeniably fine results, and could so easily have left it at that. The scores were great: no one would have been the wiser. But with a cable evaluation project also on the books this prompted still more sessions both with the loaner CH set up and my own reference control and amplification.

Not unexpectedly, mix and match comparisons demonstrated that there was more to get from the CH 1 series audio components, and with no imputation whatsoever against the Chord ST cables, it was possible that even greater spend on audiograde wire for this system could bring the reward of still better sound quality, as you can read in my review of the Argento Flow cables with the CH Precision components on pp39-40 of this issue.

All In The Set-Up
It just goes to show that we are at the mercy of installation and accessories when setting up a high performance system: with the changed cable loom the system sound was a little sweeter, also improved in dynamic expression, in low frequency slam, in bass tune playing, in image depth and focus – in fact, gains all round.

Revisiting the P1 phono stage, the current inputs in particular are state of the art with an exceptional and low noise floor. If the X1 auxiliary power supply is shared with the L1 line control, it certainly provides a good value sound quality upgrade to both the P1 and L1, nonetheless noting that both of these remain really good performers as stand alone designs.

The L1 continued to impress perhaps in the way that it did not get in the way of signal sources: indeed, it was hard to pin down, seemingly having no character, but was ultimately valued for just this quality. While the A1.5 power amplifier could be seen as the muscular extrovert exhibiting significantly more grunt than the still highly capable A1, the L1 impressed with its ability to disappear from the signal path, almost magically seamlessly selecting inputs and controlling loudness – the latter over a huge dynamic range, faultlessly and with absolute neutrality.

Looking back, even without the X1 augmentation the L1 remains a superbly executed example of the art, and of note are the inbuilt pillar isolation and vibration control systems which certainly add convenience to the physical installation of CH audio components, and performance to this product line.

Finally moving to the A1.5 power amplifier, I might have expected a modest upgrade to the A1, which itself was a fine performer having earned an Audio Excellence award in HIFICRITIC Vol10 No 4 Oct-Dec 2016. However, I was actually rewarded with what felt like a doubling of power, but also with further gains in drive, bass tune playing, transparency, image depth, micro detail and not least listener involvement.

When the review system was fully optimised, at least given the resources available, it was obvious that the A1.5 offered state of the art image depth and transparency, a quite remarkable spatiality, and that – within those exceptionally large, if virtual, acoustic spaces – sound sources were both exquisitely placed and focused.

This was acoustic holography of a very high order, while bass lines were highly neutral, well timed, crisply defined, with explicit tune playing and revealing of much unsuspected detail in familiar recordings. With those massively upgraded reservoir capacitors and the much bigger power transformer, this really was a step-level gain in overall quality, and not least in dynamic range. In this respect I was somewhat reminded of the conspicuously larger Statement power amplifier from NAIM.

Thus may I conclude, with even greater conviction, that the CH '1' series continues to set a very high standard, in context at a rather fair price considering the most comprehensive nature of the build, facilities, upgradability, versatility, vibration countermeasures, technical performance, operability and – not least – overall sound quality.

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Manufacturer
CH Precision Sàrl
ZI Le Trési 6D
1028 Préverenges
Switzerland

Voice: +41 (0)21 701 9040
E-mail: info@CH-Precision.com 
Website: CH-Precision.com