The Berkeley Audio Design Alpha DAC is a long-running favorite amongst reviewers and audio nerds.

The "D is for DAC" digital to analog converter

Berkeley Audio Design essentially makes just two products, a DAC and USB converter, offering each in a reference model and a regular model. Its DACs have been in production for so long and are so well regarded and thoroughly updated, that the Berkeley Audio Alpha is practically the epitome of the external DAC.

At our recent Fyne Audio event, we showcased the new $34,000 Berkeley Audio Design Alpha Reference DAC Series 3P in the main system, and it is a must-audition. Not everyone is at that price level, so let's also talk about the Alpha Reference's little sibling, the $11,000 Alpha DAC Series 3.

When writing about the Berkeley DACs in the past, we've talked about how they bring together two sonic qualities that are irreconcilable in lesser DACs. These fall roughly into two categories:

1. DACs with a warm, rich sound with a lot of harmonic weight, but are not detailed, and can often get blurred or confused as the music gets complex. The background singers sound musical and full-bodied, but you can't tell how many there are.
2. DACs with a clean and detailed sound with great separation, but are lightweight and even clinical. You can count the background singers, but you don't hear them singing from their chests.

Great DACs, and both Berkeleys are no exception, combine the best qualities of both, bringing detail, separation, and clarity, along with harmonic weight and richness. The only way to achieve this, is to push beyond all reasonable levels of obsessiveness. Both Michael Ritter and Michael Pflaumer of Berkeley Audio Design, talk about how they take improvements to DAC design to the very limits of measurability, yet every minuscule change makes an audible difference.

You'll notice that both the Alpha Reference and Alpha proudly call out "Ultra-low-phase-noise conversion clocking" as a stand-out feature, and this is one of those areas where Michael Pflaumer has gone so deep, that he's had to create a proprietary oscillator—off-the-shelf simply will not work well enough.

Berkeley Audio Design makes one great DAC, then creates a more affordable version, losing as little as possible.

Close-In Phase Noise

When speaking of oscillators used to time digital signals, high-end DAC designers stress on the importance of "close-in phase noise".

Phase noise affects the steadiness of the clock signal, and it is measured at various "distances" from the main clock frequency, with this offset frequency telling us a little about the type of noise and its effects. Most audio-grade oscillators boast impressive phase-noise figures at a 1 kHz offset, but the real challenge is to get low phase noise at a 10 Hz offset, where the noise most affects audio quality.

At the more distant 1 kHz offset, we're talking about high-frequency jitter components that are less audible, and can be suppressed with low-noise power supplies and good circuit design. At the much closer 10 Hz offset, we're dealing with a slow pulse or drift in the clock's performance, and this directly affects the timing of the music signals. This "close-in phase noise" is harder to control because it's affected by temperature changes, microphonics, and instabilities of individual components. Mitigating these requires exceptionally stable materials, precision thermal control, and careful mechanical isolation.

This goes a long way in explaining why the Berkeley Audio Alpha Reference weighs 30 pounds, and even the regular Alpha is 11.6 pounds. 

This is where Berkeley's tight catalog really shines. The amazing performance of the regular Alpha isn't so much about "trickle down", but that the company really makes just one DAC, the Reference. It spares no expense getting it to be the very best DAC it can be. Then, starting with a much more inexpensive enclosure, it removes or changes the very minimum, leaving behind the very best budget version that doesn't lose that Berkeley sound.

If you're looking for a DAC in the $10,000 to $20,000 range, we strongly recommend considering Berkeley Audio Design—the most specialized DAC manufacturer in our line-up. We currently have just three Alpha DAC Series 3 in stock, all in black. Grab yours before the holiday rush!

If you're looking for a DAC in the $10,000 to $20,000 range, we strongly recommend considering Berkeley Audio Design—the most specialized DAC manufacturer in our line-up. We currently have just three Alpha DAC Series 3 in stock, all in black. Grab yours before the holiday rush!