Review samples supplied by CH Precision
Retail Price in the EU (incl 21% VAT): approx 31.000 euro
In essence, it could be argued that a preamplifier’s main function should be to allow multiple inputs to be switched and volume-controlled while being inaudible and the L1 succeeds in realizing this ideal to a larger extent than I have heard any preamp do so far. If that sounds like faint praise I should add that, in my opinion, no active preamp is truly inaudible. After all, you are inserting extra cabling, connectors, and active stages into the signal path. What any preamp can hope for at best is to approach as closely as possible the integrity of the original signal. A popular means to achieve this is to minimize the signal paths both in component count and signal path length.
I’ve owned preamps that take the short signal path ideal to extremes, for instance, the Jeff Rowland Synergy that had its entire circuit on a tiny PCB that fits in your hand with basically only a couple of IC’s and a set of input/output transformers. This preamp was highly refined, the antithesis of dry and excelled in treble airiness but it was also overly smooth and relaxed. In retrospect, while it was highly refined, it was not particularly transparent. Much later, I owned the Jeff Rowland Corus which used a large ceramic PCB with even fewer components, basically only input transformers, a pair of OP-amps with a reportedly even shorter signal path than with the Synergy, a volume IC and output transformers. This preamp was considerably more articulate and transparent than the Synergy but as a comparison with other preamps would later establish, a more direct, more dynamic, and timbrally even purer sound was possible. But no preamp I used so far was actually inaudible. All of them possess a certain house sound, a certain character.
Although electronics will always provide an approximation of the real event, of course, the aim should be to identify those that add the least of their own character while avoiding the pitfall of lacking expression and becoming essentially lifeless.
Naturally, an analog preamp is a prerequisite when there is a traditionally-equipped turntable in the system. But besides this, a preamp also forms a central connection point for multiple source components and it avoids the loss of resolution which occurs when using digital volume control.
The quality of a digital volume control is highly dependent on how loud the music is played. The C1 volume control is a hybrid system where 6dB coarse steps are applied in the analog domain while fine 0.5dB steps are applied in the digital domain. The C1 is equipped with two of these coarse steps, meaning that below -12dB on the C1 display, lower volumes are applied in the digital domain. If music is listened to with a setting between 0 and -12dB, then the C1 is used in the best conditions. Below that, music reproduction will suffer from a loss of dynamics and the lower the volume the more noticeable it gets. With an analog preamp such as the L1, the C1 becomes a pure DAC and its volume control is fixed to full scale, maximizing its performance.
Finally, an analog preamp also provides an ideal input- and output impedance, allowing even source components with low-power, high-impedance output stages to perform to the best of their ability while driving long interlinks and insensitive and/or low-impedance power amp inputs perfectly well.
Naturally, the L1 performs all the basic functions that are expected of an analog preamp but it adds significantly to this with a very wide range of settings that offer the user complete freedom in controlling how the signals are treated. Volume control is done using two R-2R ladder networks per channel in balanced mode. Tight tolerance high-grade metal film resistors are used as well as fast-switching, distortion-free analog switches to precisely and silently adjust the listening level in precise 0.5 dB steps. All of the L1’s parameters are accessible via the front panel display and the unit’s 3D multi-function rotary control as well as very comfortably from the listening position via the Ethernet-enabled CH Control Android application on a tablet. The inputs can be freely labeled, set to variable or fixed and they can be disabled if they are not used. The L1 also offers the option to select between 600 ohms or 100 kOhms for any of the 4 balanced inputs and between 300 Ohms and 50 kOhms for each of the 2 single-ended BNC and cinch inputs. The absolute phase and the gain can be set for each input independently. The output is available on XLR, cinch, and BNC and all these connections can be used simultaneously.
Some source components have DC on their outputs. Normally, this is carried over and can cause issued downstream. Further, DC voltage in an R2R resistor network circuit topology (the L1’s volume control) translates into audible clicks in the audio signal when a volume change is applied. I’ve actually heard this phenomenon before with several preamps in the past but never realized that DC was the cause of it. The L1 features an advanced DC offset cancellation system that prevents audible clicks from happening. The system works in parallel with the audio path and leaves the audio content unaltered, but DC free. In addition, the L1 even offers a “Calibrate” option to analyze the upstream device’s DC level to best adapt its DC-cancellation scheme. If the source exhibits very high levels of DC at its outputs, the L1 will reach a state where it can’t counteract the inherited DC anymore. In this case, the front panel display indicates that it recommends engaging the high-grade polypropylene DC blocking capacitor. Of course, this is a recommendation only and the user can decide whether or not to engage the capacitor on this particular input or any other input. Finally, the L1 can also measure and calibrate its own circuits to compensate for the presence of DC in any stage of its signal paths.
Like all CH Precision products, the L1 can easily be upgraded via USB flash-drive firmware. Also, like all CH products, the L1 can work in several modes. The default mode is Dual Monaural, where the L1 holds two channels in a single chassis. This is how the L1 was reviewed here. The first optional expansion mode is Monaural, where two L1s work together, each one processing a single channel, one board in each chassis. The second option is Monaural Extended, where two L1s work together, each one processing a single channel, however with two boards in each L1 chassis, allowing twice the amount of inputs. Finally, all these configurations can be further enhanced by adding one or more X1 External power supplies. (review forthcoming)
Short signal paths
Contrary to expectations when looking at its incredible flexibility, the signal paths inside the L1 are actually as short as they can be. The high-bandwidth Class-A circuit is fully symmetrical and is built using only discrete components. There are no IC’s or Op-Amps in the signal path. Each channel’s electronics are located on individual circuit boards located in a compact separately shielded section near the L1’s connector side.
In addition, I have taken the L1 to my audio buddy Niels to also assess it in the context of his system. Naturally, I gave the L1 plenty of time to acclimatize and serious listening started only after it had been powered on for several days.
Coming from the C1 DAC connected directly to the A1.5 amp directly via a CH Precision Balanced Link XLR cable and adding in the already warmed-up L1 preamp using another CH Precision Balanced Link XLR cable, the sound remained utterly transparent, with impeccable resolution. If anything, the low-level detailing was now even better than with the C1 by itself, especially in the treble. The entire delivery was now slightly more fluid, less “square” if you will. This resulted in a more refined treble as well as a slightly less robust, but still fast and utterly nimble, bass. One way of looking at this is to say that the transients were more rounded, another way would be that the negative effects of the digital volume control are now gone. All I can say is that this slight “fluidifying” is something that I heard with all analog preamps and the L1 is without a doubt the cleanest and most transparent preamp so far. In terms of the frequency curve, the L1 seems to be ruler-flat. Of course, I have not measured this, but following countless comparisons it became clear that the L1 is never audible as being in the signal path. Tonally, the preamp is extremely neutral with only a mildy more light-footed and mildly less saturated touch than with the C1-direct.
Very importantly, with very clean audio components, sometimes, a by-product can be that the sound becomes overly analytical, or worse, edgy or hard. This does not happen with the L1: there is no added edge or hardness anywhere and the treble is superbly airy, fluid and refined.
Sometimes when adding a component to the chain, the sound can attain a more electronic signature but that also did not happen. The midrange had absolutely no added coloration and was still every bit as realistic. And most importantly, the musical message still came through loud and clear.
Yes, the L1 lets you hear deep into the mix but it is not clinical.
With the L1, the sound is tonally slightly lighter and airier but with a very involving sense of flow. With the C1 DAC connected directly to the A1.5 amp, the sound was more sonorous and articulate and tonally fuller but also comparatively drier and more matter-of-fact. As a practical example, with the L1 in place, I was much enjoying the acoustical bass of a Diana Krall track and found that I could perfectly follow all of the instrument’s notes while the rest of the music wrapped around me in a very involving manner and I found myself drifting away into the music. When switching to the DAC direct, the bass plucking became more immediate but the sound was also drier and there was less flow and less of that engaging wrap-around soundstage effect. Was the former more engaging but the latter more realistic? Not knowing what the original performance sounded like in the studio, this is impossible to determine and it remains a matter of interpretation. I will say that the emphasis with the DAC-direct route is more on the percussive elements while with the L1 in the chain the emphasis is more on the flow and the overall musical message. And the more I listened to the L1, also as a central part of other reviews, the more I came to rely on the predictable results due to its even-handedness and utter neutrality.
At some point, I paired the L1 with the Aqua Formula xHD DAC, not a component known for sounding rich or warm but the combination made music in a manner so effortlessly fluid and engaging and yet so incredibly hi-res that it formed the basis for several other reviews.
As the L1 is so incredibly non-colored, it perfectly allows other components’ to shine precisely as they are. The same goes for all the different interlinks that I tried, each one sounding as different from one another as I know they do. The L1 works just as well with balanced interlinks as it does with cinch cables but because I have a much more extensive XLR cable collection, that’s what I used predominantly.
While I am verging more and more to a sound as transparent and neutral and as natural as possible and, for that purpose, the CH Precision Balanced Link remains the most neutral cable that I tried, arguably even better results were obtained when using Vermouth Reference interlinks. Or maybe I shouldn’t say better but rather more pleasing. The Vermouths retrieve as much detail as the CH Balanced Link but if the quest is to obtain a sound as unadulterated as possible then the Balanced Links remain the prime choice. But if one seeks just a smidgeon extra harmonic richness and sonorous solidity, then the Vermouths work fabulously. These cables enrich the sound in a very natural manner while avoiding sounding in any way overly polished.
I tried Cardas Clear as well and while I like this cable’s fluid transparency and still use it predominantly when playing analog records, ultimately, I find that it sounds too polished and ever so slightly rounded on the transients. And so, I don’t use it with digital sources. The Final Touch Audio Ganymede, finally, sounds midway between the Cardas and the CH Balanced Link, which, again, is precisely how I have found it to sound in all the prior combinations. This cable has a sound that seems to be soft at first but then opens up to reveal an immensely transparent and ultra-refined sound that makes it so easy to slip away into a dreamy state while listening to music. Ultimately, the L1 does not seem to have a preference for any one cable of another. The decision, therefore, lies entirely with the end-user.
A change of scenery
So far, I have not been able to compare the L1 to another reference-class preamp. So, I took the L1 to my audio buddy Niels to hear it in his system and to compare it with his Spectral DMC-30SV preamp.
Set up under identical circumstances (same power cable, same interlink, same support type) with music sourced from an Aurender S10 feeding a Zanden 5000 Signature DAC and using the Soulution 711 power amp with Magico Q5 speakers, it was immediately evident that the L1 is a full-blooded CH Precision component. Just as with the CH A1.5 power amp in comparison to Niels’ Soulution 711, the L1 excels in transparency and accuracy and by resolving subtle sonic clues more instantly and more clearly.
Especially soft percussive sounds are startlingly realistic with the L1 but without adding any hardness. The Spectral preamp, by comparison, is less articulate and offers a richer, rounder, and smoother sound with a darker overall balance that happens to work well with the extremely finicky Q5’s. While some listeners may accuse the L1 of being overly analytical when coming from the Spectral, it is actually even more fluid and refined and just actually extremely highly resolving. That’s not the same as being clinical. The L1 just reveals more of what the source sounds like while overlaying virtually no character of its own.
No preamp that I used so far has been truly inaudible. All of them possessed a certain house sound, a certain character. But not so the CH Precision L1. It is easily the most transparent preamplifier that I have heard. It is extremely revealing but it does not obstruct warmth, smoothness, or richness. If it is in the recording, it will be relayed.
More impressively, that the L1 manages to be this extremely transparent, precise, articulate and refined while offering absolutely unmatched flexibility makes it a reference preamp to recon with. And that it captures this performance and flexibility in such a beautiful design really puts the cherry on top.