This design team is extremely focused
on reducing noise levels in all circuits. They view this as key to obtaining higher resolution. Each channel, every stage and system clock has its own very low-noise power supply regulator to isolate the sensitive circuits. The DAC212 uses no fewer than 12 independent very low-noise local power supply regulators. As the heart of their converter, DiDiT chose the renowned ESS Sabre ES9018 Hyperstream™ 32-bit chip, a safe choice which quite a few great DACs have embraced to exploit its eight channels. DiDiT also use the 2x4 route.  But just as with cars, you can have a great high performance engine yet if the rest of the chassis, steering, suspension and what not suck, you will still end up in the ditch.

From Sebastiaan’s notes, we’ve already learnt that noise reduction in the power circuitry had a lot of their attention. Another DAC issue is jitter. We know that any transition point of signal formatting is inherently weak. That goes for software where transitions from one protocol to another are vulnerable to cyber attacks. Something similar happens in electronics. Some Sabre designs offer an additional external filter instead of the built-in filter capacities of the chip. DiDiT follow the adage that the less you manipulate the signal, the more transparent it stays. With the next software upgrade however, the user can choose her own filter setting from the Sabre’s menu options via the upcoming DiDiT app. Currently the default filter setting is ‘neutral’.
Jitter and clocks go hand in hand. To achieve the most stable low clock jitter, here Crystek Femto clocks do the ticking. Another deliberate choice at DiDiT HQ was to go after a switched power supply. Where others create elaborate linear power supplies, the Dutch chose a British PowerPax PCB-mountable SMPS but added extensive post filtering followed by extreme low-noise LDO voltage regulators. In total the DAC212 is equipped with 12 of these power supplies. The most recent measurements on the DAC212 show that the S/N ratio is a whopping minus 135dB. This suggests how this low-noise approach plays all the right notes. At the DAC chip’s output sits an OPA1612 opamp for current amplification and for the differential amplifier an OPA1611 combines with a LME49600. So yes, there is a headphone output. Voltage swing of the power supply is +/-12Volt while the output is a nice standard 2.0Volt at 0dBFS. User who need more can set a jumper—in fact two as the design is fully balanced—for an extra +6dB gain i.e. 4.2Volt RMS at 0dBFS. This jumper setting can be required as well for certain low-efficiency headphones. Output impedance is 1.6Ω @ 1kHz.

Next to being a regular DAC, the DAC212 offers said headphone output and thanks to the ESS Sabre’s full 32-bit resolution can use the last 8 bits for volume control without (much) quality loss. We added the ‘much’ qualifier as we know how steep digital volume attenuation does impair signal quality. When the 2Volt output really is too much for a direct-coupled power amp/loudspeaker load—aka system mismatch!—because it blows out the windows, one is better off with a passive analogue attenuator as we do with our custom-wound Music First Audio TVC. A little volume attenuation done digitally is no problem however. DiDiT suffered from what many manufacturers before them have encountered: it’s hard to get your case work done to spec. One sample is made to perfection, the next completely off. It took several metal-working companies to fail quality and consistency tests before the right one was found. The same held true for the anodizing plant. At last a reliable partner was found, one who by the way also works for the top German car industry whenever surface treatments are applied.

The DAC212’s case is first milled, then finely ground before the final milling phase applies the beveled edge. We were warned upfront that our review sample had been culled from a reject case lot. That case sits on three rings of Sorbothane. The rings’ dimensions and thickness correspond with the DAC’s own f0 and thus dampen that frequency. There are three turned stainless steel footers mated to the Sorbothane rings to further isolate the DAC from the outside world.

Our correspondence with Rients netted the above background as we waited in anticipation for the Dutch DAC which arrived as promised. What hadn’t been promised was the extraordinary packaging – not the standard double-box cartons but the actual DAC packaging inside. DiDiT’s Roy designed a box with lid fully out of pressed cork. What is good for wine is good for audio. Cheers.

Adorned with the company’s delta logo, lifting the lid showed a compartmentalized division below. The DAC, remote control and power cable all have their own bunk. The lid offers space for the quick-start manual which was still at the printer’s but sent in the mail when it became available. Holding the DAC212 creates a reassuring feeling. The smooth cool case, the weight of 2’700 grams and 21x21x4cm  size with the logo on top slightly hint at Apple’s Mac Mini. But that design echo is merely faint as the front has an indent of which the top half is perforated with a 29x8 dot matrix above the capacitive touch power switch. Somewhat higher and to the right of the power switch sits the headphone port next to the IR receiver for the remote.