When Leo from Orchard Audio contacted me and asked me if I wanted to take a listen on his new creature, I surely got impressed by his claim to have created an “Ultra High Performance DAC” for the Raspberry PI. So he got me with that, I was extremely curious to see, and most importantly listen, to the ApplePi DAC.
The ApplePi DAC is a dual mono DAC, like we’re used to seeing in the higher-end I2S DAC scene, but unlike the direct competitors that use ESS or AKM based ICs, the ApplePi DAC features two of Burr Brown’s flagship PCM1794A DACs. The DACs are configured in monaural mode achieving a maximum rated 132-dB S/N of the DAC. Some of you might remember that the very same DAC IC was used by Torsten Jaekel in his RPI-DAC (one of the very first I2S DACs made specifically for the Raspberry PI). In this monaural mode, the PCM1794A DAC will offer balanced output. ApplePi DAC features onboard balanced (Mini XLR) and unbalanced (RCA) outputs driven by dual differential output circuit stages, a feature that is certainly appreciated. On paper, the ApplePi DAC should deliver about 132-dB S/N, way higher than the average I2S DAC.
An interesting design choice of the ApplePi DAC is the fact that it does not use crystals to generate a Master Clock (MCLK), as we’ve seen in some DACs with “Audiophile credentials.” Instead it uses a CS2300 IC from Cirrus Logic, which integrates a crystal, PLL, and clock multiplier into a single device. Leo explained to me that he was forced to this design choice because PCM1794A has no way of deriving an MCLK from a crystal, and to get around this issue and still generate a low jitter MCLK, he therefore ended up using the CS2300, and he claims that even though he’s using the Pi’s LRCLK, the jitter from it is reduced to almost nothing, as input jitter is attenuated by 60dB (1/1000).
So, on paper we have a dual mono DAC with impressive S/N, extremely low THD, and a very low jitter clock; the ApplePi DAC looks like one of the all-time best I2S DACs.
But how good is the ApplePi DAC at its job? Immediately after playing my reference tracks, on my main system, something was immediately clear. This DAC excels on all the parameters I love. This DAC is producing the most detailed sound to ever come out of my Raspberry PI, all the subtle nuances of my test tracks were there and clearly distinguished from everything else. Instrumental separation came along with it, and I must admit that in this respect, this DAC outperforms my reference USB DAC (Opera Consonance Don Curzio) which cost a lot more.
The sound signature appears to be positioned on the extremes of the audible band: lower frequencies are very present and bass is quite “punchy,” the same applies for the higher ranges, where you can definitely hear a “bright” approach of this DAC. To make an impolite comparison, this DAC reminds me of the sensations I had when trying Klipsch loudspeakers (and I much more like the “laid-back” English sound, rather than the irreverent Klipsch’s).
Unfortunately, this DAC lacks a bit in PRaT (Pace, Rhythm and Timing), which does not make sense to me: I would have expected it to deliver very good PRaT due to the careful clock design.
Sound-stage and spatial resolution are just excellent.
All in all, when it comes to detail and instrumental separation this DAC is second to none. However, I would have appreciated a more balanced sound signature: the combination of hyper detail and the “compressed to extreme” sound produces a slight listening fatigue when used in “bright” systems (like my studio one). This effect is greatly compensated for in my main system which is quite “laid back.”
One major disadvantage, coming from the design choice of the DAC IC and clocking mechanism, is that this DAC does not have hardware volume control, so bit-perfect volume control is not available.
My conclusion is that this DAC is for sure one of the best 3 DACs (together with Allo Piano 2.1 + Kali combo and Terra Berry DAC2) for Raspberry PI at the moment. If you’re into hyper detailed sound and your gear can balance the “vivid” sound signature of this DAC, you’ll surely love it.