Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.

Marcia likes to wake up earlier than I do. On weekdays she gets up around 5:30 a.m. and writes in her journal for about 45 minutes. She sits in our darkened living room, and she lights about a half-dozen candles, including one thick beeswax job that ends up with a giant wick.

It’s a lovely sight that greets me when I shamble downstairs at 6:00 a.m. There she is on the couch, with the dog beside her, backlit by candles. It’s like waking up to a scene from a Rembrandt painting.

There’s always music playing. Often it’s either Brian Eno’s Music for Airports or John Zorn’s Alhambra Love Songs running off the music server and piped through the Estelon YB speakers.

Angela-Gilbert Yeung

The music plays at a louder volume than you’d expect, given the situation. Marcia isn’t afraid of music—she likes to physically experience it. After she goes to work and I sit down to write, I often spend a fair bit of time listening through the secondary system on the main floor. But my daytime needs are totally different from Marcia’s. I’m using the music in tandem with my second coffee to get me going, to light a fire under my ass.

I’ve often thought that having two separate systems on the main floor would be great. The Estelons are just wonderful—no need to change them. It’s the amplification I would like to modify. For Marcia’s candlelit mornings (she’d look at me like I wasn’t right in the head if I suggested this), I think there should be tubes in the system. Partly because of the look, the glow. But more for the burnished richness they’d add to the sound, to the whole gestalt.

My afternoons are a solid-state constellation. Espresso, a stiff chair with good lumbar support, and the sun streaming in, revealing the Brownian motion of dust suspended in the air. My Hegel Music Systems H120 makes it so, with its crisp Nordic presentation.

But what if it were possible to use the same component to infuse music into Marcia’s sepia-hued mornings and my glacier-sharp afternoons? That’s a question that may be answered by this review if you’ll only keep reading.

Welcome back in a different form

I’ve had a long relationship with Angela-Gilbert Yeung’s products. Blue Circle Audio—do I really need to say more? For nearly 20 years, Blue Circle Audio was an anchor in the world of Canadian hi-fi. Yeung ended up closing down Blue Circle Audio, stepping back from manufacturing, and began to focus on design and engineering. Most recently, the Saturn Audio 401 phono preamplifier, which Yeung had a hand in designing, blew my socks off.

Angela-Gilbert Yeung

And now Yeung’s back at the forefront, back on the audio show circuit, and back with new and appropriately mercurial products, including the C312 preamplifier, which I’ve spent the last couple of months trying to make sense of. I’ve got it figured out now, and I’d like to share it with you.

What the hell

On the face of it, the C312 ($6300, all prices in USD) is a two-chassis preamp, comprising a main unit and the GC312 external power supply. The C312 is not fully balanced, but it is equipped with two balanced inputs and three single-ended inputs. My sample was equipped with two balanced outputs and one single-ended output, but the stock version comes with one balanced and one single-ended output. The external power supply connects to the preamp via a braided cable with a four-pin XLR connector.

Angela-Gilbert Yeung

The power supply has two additional DIN connectors to accommodate A-G’s optional capacitor packs. Angela-Gilbert is a firm believer in the benefits of adding lots of capacitance to their products, and at the 2022 Toronto Audiofest, George Taylor of Entracte Audio—Angela-Gilbert’s Toronto-area dealer—gave a convincing demo during which he added farad after farad of capacitance to the amplification chain while replaying the same track. As Taylor added capacitance, the sound became smoother, and the decays of notes lingered longer.

The Cap Pack 5 adds 500,000μF of capacitance to the C312 and retails for $710. Plug the Cap Pack 15 into the back and you’ve added 1,500,000μF of power-supply capacitance. This will set you back $2085. The top-line Cap Pack 36 delivers 3.6 farads, which is an ungodly amount of capacitance. It retails for $3335. All my auditioning was done with the stock GC312 power supply.

While I didn’t unbutton the C312, I could see through the ventilation slots that the innards were festooned with artfully applied swirls of colorful silicone. This is something I recall from my Blue Circle days. “Silicone,” I recall then-Gilbert saying, “has great damping characteristics, and it glues things down really well. And it’s cheap! Why wouldn’t I use it?”

Angela-Gilbert Yeung

The C312’s chassis is made from sturdy steel, and the top cover feels somewhat undamped. The front panel consists of two slices of plexiglass, the deep, translucent burgundy backing panel, and in front, a black piece that’s gently curved, evoking an analog waveform. Dead center on the front panel is a backlit circular cutout that glows a nice muted blue. This flourish is a straight-ahead callout to the Blue Circle products that Angela-Gilbert crafted back in the day.

The controls up front are flanked left and right by two large dials: one selects between the two balanced inputs and the flight of single-ended inputs, and the other is the master volume control. Should you choose to set the large selector to its single-ended setting, you’d have to manually choose which of the three inputs you wanted to use. You flip the in-use toggle switch up and ensure the other two are flipped down. I wasn’t sure what would happen if two switches were in the up position with music playing through both, but it felt like a very bad idea, and for some reason, an atavistic part of my brain said don’t do it! After conferring with Taylor, I discovered that nothing bad would happen—I’d just hear both inputs playing at the same time.

Angela-Gilbert Yeung

The C312 ships with a cute little remote with two buttons for volume—all anyone really needs—which I could imagine attached by a ring to a piece of hockey stick, just like the key to the toilet at a gas station.

The most obvious, unique characteristic of the C312 is its three dials, mysteriously and ominously labeled Warm, Tube S, and SS. The latter two are marked below each dial respectively with the circuit symbols for a tube and a transistor. The Warm dial does not have a symbol.

Here’s where it gets interesting. Each dial controls its own gain stage. The output of the warm gain stage—which, as I discovered, seems to act as a sort of master gain—is split and routed through the other two stages. “Tube S” stands for “tube simulator.” It’s another active stage with a passive network that emulates the sound of a tube. There’s no actual tube in there (although there is a 6SN7 tube and a 6922 tube in the higher-spec C318). The SS stage is a solid-state gain stage, so the tube simulator and the solid-state stage can be blended to achieve different characteristics.

Angela-Gilbert Yeung

The goal of having separate controls for each of these gain stages is to allow you to bend the sound to your preference and then use the master volume on the right to set the actual level.

The C312 sat on the top shelf of my custom-built equipment rack. For most of the review period, the C312 received signals from an EMM Labs DS-EQ1 optical phono equalizer, although I also used its baby brother, the Meitner Audio DS-EQ2. The DS-EQ1 fed the C312 via a balanced input, and the DS-EQ1 connected via single-ended RCAs. Power amplification was by way of a Hegel H30A amplifier via a balanced connection. Interconnect cables were Nordost Tyr 2, and speaker cables alternated between Crystal Cable Art Series Monet and Audience Au24 SX. As always, my VPI Prime Signature served as the source, along with my DS Audio DS 003 optical cartridge.

Just below and to the left of where I installed the C312 was my own Sonic Frontiers SFL-2 preamplifier, an all-tube design that employs eight 6922s. Even though the SFL-2 is jam-packed with tubes, it doesn’t sound overtly tubey. Actually, it’s fairly neutral. The SFL-2 functions as a great reviewing tool, and over the years, it’s given me great service without my having to think about it much.

Angela-Gilbert Yeung

So when Taylor asked me how I wanted the C312 to sound, I pointed at the SFL-2 and said, “Make it sound like that.” The Hegel H30A amplifier is quite sensitive—it doesn’t require a high-level signal—so Taylor set all three stages near the nine o’clock mark. He then set the Tube S control just a tad higher than the SS control, and we sat back for a listen.

Roll with it

Well yeah, my first exposure was a positive experience. I totally expected the C312 to sound good at worst, and superb at best. Yeung is a stone-cold genius. I’ve reviewed a number of Blue Circle products in the past, and while they were all rather quirky—the yellow- and red-painted but spectacular-sounding BC202 amplifier comes to mind—they’ve all done something that made me sit up and take notice.

As I’m writing this, I don’t recall exactly what Taylor and I were listening to, as there was lots going on with me trying to get a handle on how those gain stages worked together. At the time, it wasn’t clear to me, so I just took a photo of the baseline settings that Taylor had suggested—in case I started spinning dials and couldn’t get back to where I started—and rolled with it.

Angela-Gilbert Yeung

Initially, I found the process of manipulating the controls somewhat frustrating. It isn’t possible to change the tube or solid-state stage without an ensuing change in overall level. Increase either of the stages and the overall volume goes up, so you’ve got to lower the master volume or the Warm dial to bring it back down. This stops you from hearing the change in isolation. Ideally, if you turned up, say, the tube stage, the volume would remain consistent, you’d hear the result, and it’d be easy to tell what exactly it was bringing to the show.

This was more than a little confusing. I have reasonable faith in my ability to figure things out. It’ll come, I thought to myself. So I said, screw that action and decided to just listen to the thing for a while.

My initial impressions, once I’d stopped worrying about how to deal with those knobs, were of deep silence. With no music playing, the C312 was coal-mine silent. When I turned up the volume knob full blast, it was near-as-dammit still silent. More than that, I had a sense of almost additive blackness. Similar to the way black velvet seems to suck in light rather than just not reflecting it, the C312 projects music out of a deep tunnel of darkness that’s actually blacker than dark.

Angela-Gilbert Yeung

If you’re going to die of a broken heart, Astor Piazzolla’s music will help you along with style. Early in the review period, I put Tango: Zero Hour (LP, Pangea PAN-42138) on the VPI and let it rip. As I listened to “Milonga del Angel,” I found myself starting to drift away from my seat in my basement. I was back in high school, breaking up with my first girlfriend. This breakup was an asteroid about to smash into the earth, the end of the world, a mass-extinction event. I felt the C312 projecting the music, keeping that deep acoustic bass in check, flowering the violin like a blossom. And through it all the C312 maintained an underlying feeling of distance, of peace.

It didn’t recess the soundstage—it didn’t create distance in that manner. There’s a part just past midway through “Milonga del Angel” where the violin fades out and Piazzolla’s bandoneon ramps up. That transition is magical. The bass and piano recede, and the C312 presented that demarcation as if it were appearing out of an enormous void. The space around each instrument was superb, and I got a wonderful sense of the C312 spotlighting the interplay between the violin and the bandoneon. Through my SFL-2, playing the same piece gave me less of that light from above feeling, less of a lateral recession of the other two instruments. So, set as it was, the C312 was, for the most part, neutral and expansive, with a nice, tight grip on the bass.

Deep into the review period, I felt like I’d gotten a handle on the C312’s sound. I’d just received the DS Audio W3 optical cartridge and matching phono stage, and I was messing around with the cartridge alignment. The W3 is a more open, resolving cartridge than my DS 003 cartridge, and it’s got tremendous bass, so I brought the Estelon XB Mk II speakers a little further into the room to compensate. But this brought up the highs more than I felt was optimal. I looked askance at the C312 and figured I’d do some knob twiddling to see if I could dial in this modification.

Angela-Gilbert Yeung

I like tubes! So let’s crank up the tube dial, I thought. Taylor had warned me that the dial is somewhat logarithmic and small changes work best. I fully expected the Tube S dial to mellow things out, to soften the edges of the highs. Not so! While the Tube S dial did increase the warmth of the midrange and add a feeling of granularity and depth to the upper midrange and treble, it also made the highs more prominent. So I went back to my baseline settings and re-evaluated.

Next, I went in the opposite direction. I backed off the Tube S dial and increased the SS dial just a hair. Now we’re talking. This setting reduced the overall prominence of the highs, taking just a little of the biting edge off instruments like the effect-laden guitar in Talk Talk’s “Ascension Day,” from their masterpiece album Laughing Stock (LP, Polydor 00600753655191). This particular setting didn’t decrease the absolute level of high-frequency information. Rather, it seemed to just round off the leading edge of the initial crackle of the note. And there are lots of leading edges in this track. In what came to be a signature post-rock device, Mark Hollis just whacks away at the guitar, building tension in a manner that generates a feeling of manic crisis. With the Tube S dial backed a touch, there was less stridency, less overt crackle, of which there was already plenty.

Despite the changes I’d made to the tonal characteristics of the C312, it still shone out at me as being exceptionally neutral in its presentation. On the face of it, that statement is a contradiction, I realize, but I’m going to stand by it. After I’d gotten the tube-solid-state thing sorted, I threw a remastered version of U2’s The Joshua Tree (LP, Island Records B0026626-01) onto the VPI. I’ve had a long love affair with side 2 of this record, starting with “Red Hill Mining Town.” Running the remastered version over two LPs meant that I was now looking at side 3, but that wasn’t a problem, as this reissue really opens up the imaging and solidifies the bass.

Angela-Gilbert Yeung

The rejiggering of the C312 perfectly buttered up the highs of the Estelons. Giant heaps of detail now landed on me with a silkiness that took my breath away. If anything, making this change to the gain circuits increased the neutrality of the sound. I was able to relax into the music and absorb details in a completely unforced manner. The additional resolution of the W3 cartridge was still clear to me. I could hear deeper into the piled-high harmonics of The Edge’s guitar and the shimmer on Larry Mullen Jr.’s cymbals. There was still plenty of growl on the outskirts of Adam Clayton’s bass, which really could have suffered by way of the C312’s calming of the W3’s brilliance.

I’d like to make it clear that the adjustments I was making to the C312’s gain stages didn’t act like the tone controls on yer dad’s Sansui receiver. It didn’t in any way feel like I’d just turned down the treble dial. It felt more like I’d adjusted the entire temperament of the preamp and, because the preamp is the core component, of the system itself. Despite their evocative character, I’m not sure “tube” and “solid state” are entirely accurate labels, given that the Tube S dial seemed to liven up the overall sound, which is not how I’ve come to understand tube-based components.

At any rate, once I had some experience with the gain controls, I was able to see how they’d be useful. Although I didn’t really feel the need to do so, I took some extra time out from my listening chair, scurrying up to the C312 and subtly changing the gain controls to suit the mood of the music I was listening to. When things got a little hot on a slashing rock recording, I’d nudge the SS dial up just a touch and nip a tiny bit off the Tube S dial. On softer stuff, the inverse change would liven up the acoustic and put me closer to the orchestra.

Angela-Gilbert Yeung

In my conversations with Taylor, he informed me that the impacts of the controls are interwoven. Turn up the Warm dial and the Tube S dial reacts differently. The upshot here is that there’s a fair learning curve, and those three controls require some amount of artistry to blend in a repeatable, planned manner.

I guess it works!

But no matter how I changed those dials (and I never did have to change any of them by more than a one-hour increment), the basic nature of the C312 remained consistent—clear and open, resolving, and detailed, with an excellent portrayal of space—and so, so quiet. If this preamplifier did not have those multiple gain stages, it would still be worthy of recommendation.

The inclusion of those gain stages means—without a doubt—that this preamp’s not for everyone. While I find the C312’s variable stages intriguing, I’m not certain I’d make sufficient use of them to make their inclusion in my system worthwhile. That said, the one time I did need it, the C312’s adjustability fixed a problem I’d likely have had to live with.

Angela-Gilbert Yeung

Still, the Angela-Gilbert Yeung C312, which I’m looking at and listening to as I write this, is a sweetheart of a preamplifier. If my description of its variable gain stages intrigues you, I strongly suggest you give it a listen.

. . . Jason Thorpe

Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.

Associated Equipment

  • Analog source: VPI Prime Signature turntable; EAT Jo N°8, DS Audio DS 003, DS Audio W3 cartridges.
  • Digital sources: Meitner Audio MA3 digital-to-analog converter, Logitech Squeezebox Touch.
  • Phono preamplifiers: Aqvox Phono 2 CI, iFi Audio iPhono 3 Black Label, Hegel Music Systems V10, EMM Labs DS-EQ1, Meitner DS-EQ2.
  • Preamplifiers: Sonic Frontiers SFL-2, Hegel Music Systems P30A.
  • Power amplifiers: Bryston 4B3, Hegel Music Systems H30A.
  • Integrated amplifiers: Hegel Music Systems H120, Eico HF-81.
  • Speakers: Estelon XB Mk II, Focus Audio FP60 BE, Estelon YB, Aurelia Cerica XL, Totem Acoustic Sky Tower.
  • Speaker cables: Audience Au24 SX, Nordost Tyr 2.
  • Interconnects: Audience Au24 SX, Furutech Ag-16, Nordost Tyr 2.
  • Power cords: Audience FrontRow, Nordost Vishnu.
  • Power conditioner: Quantum QBase QB8 Mk.II.
  • Accessories: Little Fwend tonearm lift, VPI Cyclone record-cleaning machine, Furutech Destat III.

Angela-Gilbert Yeung C312 Preamplifier
Price: $6300.
Warranty: Three years, parts and labor.

Angela-Gilbert Yeung
Ontario, Canada