September 2009

Blue Circle Audio BC501 Digital-to-Analog Converter

Associated Equipment

Loudspeakers -- Mirage OM Design OMD-28, PSB Synchrony One, Magico V2

Integrated amplifiers -- Classé Audio CAP-2100, Zanden Audio Model 600

Power amplifiers -- Blue Circle Audio BC204, Axiom Audio A1400-8

Preamplifier-processors -- Blue Circle Audio BC3000 Mk.II, Benchmark Media DAC1 HDR, Anthem Statement D2v

Digital sources -- Simaudio Moon Evolution SuperNova CD player, Zanden Audio Systems 2500S CD player, Benchmark Media DAC1 HDR

Speaker cables -- Nirvana Audio S-L, DH Labs ST-100

Analog interconnects -- Nirvana Audio S-L, Nordost Quattro Fil

Digital interconnects -- i2Digital X-60, Nirvana Transmission Digital

The standalone digital-to-analog converter, or DAC, has an interesting history in high-end audio. In 1983, when the Compact Disc arrived, there were no DACs -- at least, no standalone models. Every CD player had a transport mechanism that read the digital data from the CD, and it also had a DAC section that converted the digital data to an analog signal that could be fed to your audio system. At the time, no one saw the need to think outside this box and, quite literally, create another one.

The mid-’80s saw the birth of the external DAC, for many reasons. The main reason seemed to stem from the fact that although no high-end company at the time could build an entire CD player on its own -- mainly because the transport mechanism is so complex -- those firms that built preamplifiers and power amplifiers could use their electronics expertise to design and build better DAC sections than the makers of mass-market CD players could or were willing to. Now, almost 25 years since the birth of the standalone DAC, they’re still relevant; people aren’t using them only to play CDs, but in computer-based audio as well.

Enter the BC501, the first standalone DAC from Blue Circle Audio, a company located in Innerkip, Ontario, about an hour from Toronto and about as far as you can get from big-city, large-scale, assembly-line manufacturing. Blue Circle’s products are all handmade, distinctively so, often by the company president and chief designer himself, Gilbert Yeung. This sort of construction is something you pay a premium price for, but for your money you get something different from another me-too box. The BC501, at $4395 USD in its basic configuration, isn’t cheap, but it’s unique in ways that only a Blue Circle product can be.


The BC501 measures 17"W x 3.25"H x 14.5"D and weighs 30 pounds. The basic model comes with a stainless-steel chassis and faceplate and a black powder-coated top plate. It can be customized for additional cost (contact Blue Circle for details). A stainless-steel top cover is one option, as is a painted-MDF faceplate in a wide range of colors, including your own choice. There’s also the option of a real-wood faceplate, the most popular being the purpleheart/walnut that the company uses for its higher-end AG-series products.

A wooden faceplate might seem odd, and the overall look of this handmade product will undoubtedly polarize buyers -- some will think it’s beautiful, others not. But Blue Circle has always done things their own way. Plus, this distinctiveness, as well as the ability to customize a component, is something many people like, and I’m one of them. I own two Blue Circle products, a BC3000 Mk.II preamplifier and a BC204 stereo amplifier, and I like the fact that they look different and have various options that I can call my own.

In the middle of the BC501’s faceplate is a round Blue Circle logo; when lit, it tells you that the BC501 is powered up. On the left of the front panel is a polarity-inversion switch, and above it are two LEDs; one indicates polarity, the other if deemphasis is engaged. To the far right is a large stainless-steel knob, used to select the appropriate digital input. The LED alongside it, when lit, tells you that the BC501 has locked to the signal from the transport.

The power-cord receptacle on the rear panel is different from what you see on most products -- it’s a Neutrik Powercon twist-on connector that securely locks the supplied AC cord in place. The BC501 is not a fully balanced design, but is said to be partially balanced inside; in the middle of the rear panel are single-ended and balanced outputs, and on the opposite side of the power-cord connector are the digital inputs. The base configuration has AES/EBU (XLR), S/PDIF (RCA, but BNC is an option), and ST fiber-optic digital inputs (replaceable with TosLink). For an extra $300, a USB connector can be added, although my review sample didn’t have this.

Blue Circle is guarded about naming the parts that go into the BC501, and they’re happy to tell you why. One reason, they say, has to do with audiophiles getting hung up on the brand names of certain parts when there’s so much more to a product’s overall design than the individual components. The ingredients are one thing, the end result another. Another is that Blue Circle feels that some of the brand-name parts favored by audiophiles either aren’t good, or aren’t good for every purpose. So instead of naming names or name-calling, they’d rather not say what goes inside at all. Instead of brand names, I was supplied with a list of specifications.

The D/A converter chipset is said to have 24-bit resolution and be capable of 44.1, 48.0, 88.2, and 96kHz sampling rates. Most companies use stock digital chips, whether or not they disclose the chips’ names, so it’s hard to distinguish a product based on that. What Blue Circle does to electrically differentiate the BC501 has mostly to do with the power supply. There are three separate stages of power-supply regulation, for the digital, digital/analog, and analog sections, and separate transformers for the analog and digital sections. There’s also said to be more than 110,000µF of capacitance filtering, which, according to Blue Circle, makes the BC501 "brownout-proof." Why do you want something to be brownout-proof? I suspect that it’s to overcome variations in the power that emerges from your wall, which is sort of like having a line conditioner built inside. A super-duper version of the BC501, the BC501ob (ob = "oh boy"), retails for $7845 and has a separate power supply with a whopping 880,000µF of capacitance. Presumably, the BC501ob can survive a blackout, at least for a while. As its handmade heritage mandates, the BC501 is meticulously wired point to point.


I used Simaudio’s Moon Evolution SuperNova CD player as a disc transport only, via its RCA-based S/PDIF output. The SuperNova cost $5900 when I reviewed it almost two years ago. I also used it as a comparison model because it’s a reference-level, all-in-one CD player; not only is its transport good, its DAC section is as well. If there’s going to be a reason for a pricey standalone DAC to exist, it must at least equal or better the SuperNova.


One of my first listening tests was with Mariza’s Transparente (CD, Times Square TSQ-CD-9047). It’s a great-sounding recording -- natural-sounding acoustic instruments, a real sense of recorded space, and a splendid capturing of a woman’s voice. The BC501 revealed a deep, rich bottom end; superbly extended highs that were infinitely airy, yet never tizzy or edgy as some digital sources can be; and a smooth midrange with a hint of bloom that made Mariza’s voice come alive.

The sense of space re-created by the BC501 was first-rate, and the performers were easy to place in that space, from left to right and from front to back. The soundscape seemed almost tangible, with presence and dimensionality. This wasn’t the flat-as-a-pancake presentation that a lot of old-school digital sound was about -- the BC501 had a bit of "heft." Mostly, though, I was taken with how Mariza’s voice was conveyed with slippery smoothness while remaining detailed and resolving. Coupled with the sense of presence the BC501 helped create, her centrally placed voice simply hung there in space, better than I’d ever heard it in my room.

The smoothness through the mids wasn’t enough to add a layer of syrup that I couldn’t hear through. I played some not-so-well-recorded discs that sound inherently coarse, particularly in the midrange and highs. This was early digital sound, recorded before most engineers knew how to make CDs sound good. Example: Bruce Springsteen’s 1987 album, Tunnel of Love (Columbia COL0040999). Not only was this album released on CD, it was recorded digitally. The BC501 didn’t gloss over its grainy midband and splashy, metallic highs, nor should it have. No high-end component should cover up a recording’s flaws -- if the recording has problems, they should be revealed.

Unlike many digital products, what the BC501 didn’t do was exacerbate those problems -- another good thing. For example, if a source component has a hard, coarse midrange or top end of its own, Tunnel of Love can sound too metallic, to the point of being annoying. Two wrongs don’t make a right, but the BC501 is a high-resolution design; it pointed out errors while never adding any objectionable character of its own. It was as transparent and clean as it was resolving.

But listening to the BC501 in isolation could tell me only so much. I learned more by comparing it with the DAC section of the Simaudio Moon Evolution SuperNova, while still using the SuperNova as a transport for both. I was able to match the levels of the BC501’s and SuperNova’s analog outputs at the preamplifier stage, as both my Classé Audio CAP-2100 integrated amplifier and Anthem Statement D2v preamplifier-processor let me adjust the input level. Then I could do an A/B comparison by using a remote control to switch back and forth between the Blue Circle and the Sim.

Most DACs won’t measure up to the SuperNova’s DAC section, but the BC501 did. In fact, with some music I found them indistinguishable. With typical pop-rock that wasn’t that well recorded to begin with and sounds heavily processed, it was always a draw -- I couldn’t tell the two apart. Even with Blue Rodeo’s Five Days in July (CD, WEA CD 93846), a well-made recording that I’ve used for years to evaluate all kinds of equipment, I found nothing on which to hang my reviewer’s hat. When I thought I heard a difference between the two components, it was usually very small. In those instances, to make the comparisons "blind," I had someone else connect the inputs for me and not tell me which was which. In every case, either the differences I thought I was hearing with this music went away, or I was so inconsistent in my choices that I realized I was guessing.

Where I did hear consistent differences was with simpler recordings, usually of acoustic instruments and with few instruments and voices, preferably spaced out on the stage. Mariza’s Transparente was one of them. I needed to hear these sounds clearly and be able to focus on them. This time the differences were there, though still quite small.

But there weren’t any across-the-board differences. The high-frequency extension of both components was equally clean, clear, and extended, with absolutely none of the steely or edgy quality that some digital gear still produces. In this area, call it a draw.

When it came to resolution -- the ability to squeak out the final bit of "air" from a recording, or to find out how deeply one can "see" into a recorded space -- the Sim got the nod, though not by much. I had to dig deep into my collection to find recordings that have air around the instruments and in which the rear wall of the recording venue is audibly well defined -- the sort of stuff you have to hear into in order to hear everything. If a fly’s burp was buried somewhere low, the SuperNova seemed to be the one that could more consistently dig it out.

Most telling was the midrange, particularly with voices. In Transparente, Mariza’s voice is so dominant in the mix that any change stands out. The BC501 sounded a touch fuller in the midrange, making a pronounced voice such as hers slightly more so. The same went for Rebecca Pidgeon’s performance of "Spanish Harlem," on Chesky Records’ The World’s Greatest Audiophile Vocal Recordings sampler (SACD, Chesky SACD323). The SuperNova and the BC501 sounded equally smooth, but the BC501 was a touch fuller overall, with a bit more bloom in the midrange. Those who fixate on voices will probably like the Blue Circle more -- it presented the midrange with a touch more presence. This was the main thing that defined the BC501 and, in my mind, made it special. Whereas a lot of digital gear can sound cold and unforgiving in the mids, the BC501 had a touch of analog richness and warmth without sacrificing detail.

The SuperNova countered with slightly tighter bass, making it the more visceral-sounding of the two. The BC501’s bass was just as deep but a touch rounder, with not quite as much impact, which was actually in keeping with the character of its mids. Again, the difference was very slight, but noticeable with specific, simple recordings that let me track the bass region in isolation.


Because it’s been about 25 years since the first standalone DAC appeared, it’s not surprising that, these days, most such products are run-of-the-mill affairs with little to differentiate them. This is especially true of the costlier models, among which are some that can be considered the state of the art. Most of what needed to be done has been done, so there’s not that much that’s new. Blue Circle Audio has been around almost as long as DACs have, but they’ve taken their sweet time in getting their first DAC to market -- no doubt they wanted to get it right. They have.

All told, the BC501 is a neutral-sounding DAC that’s faithful to what it’s fed, but isn’t neutral to the point of being boring or sterile -- it has a few traits of its own that help it stand out from the crowd. These are deep, rounded bass, coupled with a midrange smoothness and fullness that gives this DAC a hint of analog warmth. Through the BC501, voices really come alive, and the overall presentation has a weight and heft that give music presence. Moreover, it sounds good; while it won’t cover up flaws in recordings, it adds no objectionable character of its own -- precisely what you’d expect from one of today’s topflight DACs.

Notable, too, are its appearance and customization options. Even in the base model, there’s nothing, if anything, that looks quite like the BC501 except another BC501. And even then, because Blue Circle products are handmade, no two will be exactly alike -- there’s always variation, however subtle.

The BC501 is a topnotch performer that bears the hallmarks of the Blue Circle Audio name, and is strongly recommended for those who don’t mind paying a premium for something that looks and sounds distinctive, and comes with the sort of personal touch that’s possible only with handmade manufacturing and customization. The BC501 is expensive, but there’s nothing else quite like it.

. . . Doug Schneider

Blue Circle Audio BC501 Digital-to-Analog Converter
Price: $4395 USD.
Warranty: Three years parts and labor.

Blue Circle Audio
Innerkip, Ontario N0J 1M0
Phone: (519) 469-3215
Fax: (519) 469-3782