CH Precision I1 Universal Integrated Amplifier

Upending Expectations

Equipment report
Integrated amplifiers
CH Precision I1
CH Precision I1 Universal Integrated Amplifier

Having explored the I1’s DAC, it was on to the phono- stage. Since the phono board implements the same circuit as the stand-alone P1, it’s not surprising that, like that unit, the I1 extracts its signal directly from the cartridge’s coil in current mode. This is in contrast to most phonostages, which derive a signal from the cartridge’s voltage output. Aside from being more direct, CH’s approach has the benefit of liberating the user from searching for the optimal cartridge loading. The I1 does that automatically.

As it does with other analog sources, the I1 converts phono signals to digital. This has an intriguing upside: Users have their choice of phono equalization curves. Most of us are familiar with the RIAA equalization that all phonostages use to compensate for the opposite EQ applied during the disc mastering. But before RIAA gained its status as the industry standard, there were proprietary EQ curves used by competing record labels, including EMI, Columbia, Teldec, and Decca. At one time there was also a curve known as eRIAA, for enhanced RIAA.

Implementing all these EQ curves in the analog domain, as would be necessary for a traditional analog phonostage, would be a daunting exercise and basically is rarely done. The result is that if you own any pre-RIAA pressings, you’re not hearing them as they were meant to be heard. But implementing these various curves in the digital domain is a relative snap. CH took the trouble to code it, and the upshot is that a tap on a tablet summons any of the aforementioned EQ curves. With the I1 you can select any of them in real time, which makes plain exactly what the curves are doing. This feature will be a boon for collectors of early LPs.

To assess the phono board’s sound, I first listened to the Etna driving my Goldmund phonostage and linestage, with that signal then moving on to the I1’s power amp. The background wasn’t particularly quiet, which obscured some details, but the transients were superb and overall this setup produced airy, vibrant, colorful, and highly dynamic sound. Most impressive of all was the visceral level of realism that can only be heard on a great live LP played through an all-analog rig—or so I thought.

Switching to the Etna connected directly to the I1’s phono board and then continuing through the integrated amp in normal fashion, I noticed immediately that the I1 phonostage is far quieter than my reference. That allowed previously obscured details to shine. Transients may not have been quite as sharp as with the stand-alone phonostage, but that’s a nit considering that this sound, too, was airy, vibrant, colorful, dynamic, and every bit as viscerally lifelike as in the pure analog scenario. That’s quite a testament to the I1, which clearly needs no external phonostage to do full justice to LPs. 

Even if the two phono- stages had sounded identical, there’d be strong advantages to using the I1’s phono card. I’ve already described the support for a variety of EQ curves, but since even the standard RIAA EQ takes place in the digital domain, it is far more accurate than the analog implementations of other phonostages. You’ll also spend far less for this $4500 board than for an external phonostage of equal caliber, and you’ll save the cost—both monetary and sonic—of yet another set of interconnects. Lastly, the I1 board has tons of gain. This is a phonostage that allows you to take full advantage of low-output MC cartridges, such as the Lyra Etna SL that Jacob Heilbrunn has raved about (see his review in Issue 266). The conclusion is that unless you’re willing to shell out for a truly extraordinary stand-alone phonostage, there are solid sonic and functional reasons to use the I1’s board.  

The last thing I needed to know about the I1 was how well it would drive a challenging pair of loudspeakers. Fortunately, I had on hand the Bowers & Wilkins 800 D3s. As I reported in my review, these speakers sound marvelous—when appropriately powered. My Mimesis 8, despite being rated at a healthy 175Wpc, didn’t do it for the 800s; the speakers sounded dynamically flaccid and the bass was just MIA. Not so with the I1. Although rated at a lower wattage, this CH integrated must have a lot of current, for it drove the 800s to all their glory, with popping rhythms and meaty bass.

Looking Down the Road
No matter how good the I1 sounds—and it’ll definitely hook you on CH sonics—you may someday want to extend its performance. Fortunately, unlike other integrateds that are dead-ends other than for their trade-in value, the I1 was built with upgradeability in mind. I’ve already discussed the internal upgrade path from a base unit to one that’s fully loaded. But that’s just the start.

Say you want to add a pure analog linestage for your analog sources. CH’s L1 linestage will fit the bill. You can use it as an analog controller and connect it to an I1 analog input set to bypass mode. Analog sources will now go straight from the L1 to the I1’s power amp. Meanwhile, the latter can continue supporting digital sources directly. Or, you can upgrade those as well by complementing the I1 with the standalone C1 digital controller.

Similarly, you can extract better phonostage performance by supplementing the I1 with the P1 stand-alone phonostage, which can also be run through the I1 in bypass mode. If you want to complement the I1’s digital section with an external clock, the SYNC I/O board makes it compatible with CH’s T1 clock. Need a transport? The company makes a very fine one called the D1, which supports both CD and SACD. The D1 can connect to the I1 via the proprietary CH Link HD which, in my testing of the D1 and C1, proved a significantly superior way to pass SACD material. 

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