Crane Song Solaris

Dave Hill’s uncompromising converter design focuses on making clock jitter as low as possible, with impressive results.

Crane Song’s founder Dave Hill has long been regarded as one of the gurus of pro audio design. I met him at an AES convention 20 years ago, and fondly remember him very vividly explaining the design flaws of the original UREI 1176 compressor — and then ending the private lecture with the words, “I guess that’s why people love it so much.” To me, Dave is all about designing ‘perfect’ outboard, which means placing equal importance on impressive technical specifications and pleasing sound. His designs have been proven to deliver both of these time and time again, which is why I got very excited at the prospect of his new Solaris converter arriving at my studio!

Overview

The Solaris is instantly recognisable as a Crane Song product, due to the mint-green plastic knobs and Dave’s signature printed at the right-hand end of the front panel. (Its appearance might put off some hi-fi enthusiasts, but they don’t know what they’re missing out on!) The front panel contains a power switch, mute button, source-selection knob, display, gain knob, headphone gain knob and a headphone jack; both the main gain and the headphone gain controls are actually stepped attenuators. The display shows the input source, sample rate, and gain settings for the main and headphone outputs, and to the right there’s a small but informative level meter.

On the back, there are input connections for S/PDIF, AES3, Toslink and USB. Male XLRs provide the main outputs, with adjustable gain, and a pair of fixed-level secondary outputs. The main outputs are controlled by the gain knob (again, a stepped attenutor), and can output a maximum level of +24dBu, while the limit of the fixed outputs is +18dBu. Power cycling while pressing the mute button brings up a setup menu, making it possible to engage a 6dB pad on the main output, or to change the gain display so that instead of showing attenuation from 0 down to -60 dB, the display matches that of the Crane Song Avocet monitor controller, ranging from +12 down to -48 dB. The USB input is class compliant, so can be used with Mac computers without a separate driver installation, and a CEntrance universal ASIO driver is available for Windows (7 and later) machines.

The Conversion

The Solaris supports sample rates up to 192kHz. Powered by a linear power supply and designed around the latest 32-bit AKM converters, a combination of proprietary analogue and digital reconstruction filters, and discrete output amplifiers on the main outputs, Dave Hill’s fifth-generation Quantum D-A converter is the result of two years of research, a good chunk which was spent finding ways to reduce the internal jitter.

We’ve seen product literature boast about ‘ultra-low jitter’ for many years now, but it is important to note that manufacturers haven’t been using a single standardised test for jitter. Consequently, the numbers quoted in specs are of little use in comparing products. Nonetheless, I am left with absolutely no doubt that Dave Hill has created a stunningly good converter, and possibly with the lowest measurable jitter of any D-A converter to date. The Solaris uses asynchronous sample-rate conversion and an extremely low-jitter reference, and upsamples the incoming digital signal to 211kHz. Hill’s measurements have the internal jitter at less than 1 picosecond, and in the audible frequency range, around 0.045ps.

Given the quality of the Solaris’s internal clock, you might think that it would be nice to have a word clock output, at least for use in playback-only systems (whenever you’re using A-D converters, as you would in recording situations, it’s better to sync to their clock). But, as with similar designs by Benchmark and Crookwood, the Solaris’s clock runs at 211kHz to allow the best performance from the D-A converter, and this can’t be switched to provide the standard rates required of a system master clock. To make it useful as a master clock, Dave Hill would have had to add a lot of quite complicated sample-rate conversion technology that no one would really want or need, and which would add significantly to the cost — and even if he had done so, the hoped-for low jitter wouldn’t survive anyway!

The Solaris sports main and secondary output pairs, and a variety of digital inputs, including a USB connection for use with Mac or Windows machines.

The Sound

Measurements are all well and good, but they only tell only half the story. What’s most important about any audio gear is what it sounds like, and when it comes to stereo D-A converters, that translates to its audible effect — or lack of it — on the sound stage.

After I’d hooked up the Solaris to my monitor controller, putting it to work was a pure joy. Listening to some of my reference tracks quickly showed what a marvellous-sounding converter it is. The low end is deep and punchy, more detailed and uncluttered than my other (high-quality) converters. The mid-range sounded very ‘alive’ to me, and the high end smooth yet detailed. Enjoying a couple of Patricia Barber songs — which were recorded and released at 24-bit/192kHz — revealed an incredibly natural sound stage, with a stunning vocal performance that seemed to jump right out of my TAD speakers. The definition of the double bass made me respect both my speakers and high-sample-rate recordings even more. Moving on to Alison Krauss and Union Station’s Paper Airplane, recorded at 24-bit/96kHz, the transient integrity of the whole arrangement almost felt like a new recording to me, because I was able to listen further into the mix and get carried away by the microtonal shifts made by the best bluegrass musicians around. What a great experience!

The transient response is defined, without a trace of emphasis at any frequency; it makes well-recorded drums and acoustic guitars sound just as they should. The mid-range is vivid to say the least, again without emphasising the upper mids when the levels get hotter. There’s a ‘smoothness’ to the mid-range, which can probably be attributed to the very low distortion of the Solaris. The stereo panorama is equally impressive, with a natural and very believable soundstage.

In short, this is the most transparent-sounding and yet also musical-sounding D-A converter I’ve used yet, and I’ve used quite a few.

Monitor Controller

Using the Solaris as a monitor controller is a breeze, and with no analogue relays, volume changes are achieved without any clicks: I did notice that there was sometimes a faint glitch when changing the volume, especially when listening to bass-heavy music, but this wasn’t something that disturbed me. Changing the input source is achieved simply by turning the Source knob — there’s thankfully no fiddly menu to navigate.

The headphone output has its own volume knob, and trying out a couple of different headphones confirmed that there’s plenty of gain available; the headphone amp will drive the most stubborn headphones with ease. The sound has a depth and detail that I normally don’t associate with headphone amps. I found myself listening to music for quite some time, enjoying the uncluttered low end, smooth mid-range and coherent stereo panorama presented by my headphones. It’s a good thing that the headphone volume is displayed on the front panel, as this can help you to keep the listening volume at a healthy level — it’s all too easy to keep turning things up, and all the more so when it sounds so beautifully clean and detailed.

In Use

One of the things I noticed when I used the Solaris as a monitor controller was that the precise soundstage and stereo panorama, in combination with the incredibly detailed transient response, led me unconsciously to monitor at a slightly lower volume than I do usually, which was nice. In comparison with my other digital converters, the low end sounded slightly less ‘warm’, even though it went ‘deeper’ in frequency. Balancing instruments and solving the frequency-spectrum puzzle felt very easy.

The numerical volume display on the front panel makes it easy to make a mental note of a standard listening level, which is very handy when you momentarily raise the level to properly monitor tweaks done to the low-end, as you’re able to return to exactly the same listening level as before. I can’t stress enough how important it is to be able to do that.

Even though the Solaris was hooked up directly to my power amp during the test period, it never produced any pops or glitches when turned on or off, or when the input source was changed, which is reassuring — and something my speakers were very happy about!

Solar Power

The Solaris is a very well-made and fantastic-sounding D-A converter. Dave Hill has evidently gone to great lengths in the design of the digital clock circuitry as well as the analogue parts of the unit. Of course, not everyone will be able to justify the investment in a high-quality D-A converter such as this, and you must get a few other things lined up, such as speakers, headphones and room treatment, before you’ll notice the differences when monitoring. That said, if you record to an external device via your D-A converters, rather than bouncing files ‘in the box’, then any jitter artifacts will be printed whether you can hear them or not — so this is another situation in which the Solaris would excel.

If you’ve got your studio to that point, and you are looking for a high-quality D-A converter, the price of the Crane Song Solaris really doesn’t reflect the amazing sound quality it offers, especially given the fact that it can also act as a simple but effective monitor controller. So if you’re thinking about upgrading your monitor D-A converter, or you want to upgrade the sound of your analogue transfer path, or even if you just fancy listening to music with the best possible sound quality, the Crane Sone Solaris should be high on your wish-list.

If you want a measure of just how good I think the Solaris is, well, the review unit incorporated itself so well in my studio and in my workflow that I couldn’t bear to send it back to the distributor — it’s now serving as my main monitor controller.