After giving the Okto additional burn-in (40 hours at this point), I wanted to share a more detailed comparison to my previous dac, the Auralic Altair.
My system at present:
MacBook Pro running Roon core > streaming Tidal and CD rips through RAAT > ethernet into Okto > balanced output to Mjolnir Audio KGSSHV > Stax SR-007 MK1
Appearance and general use
The Okto dac8 Stereo has a very minimalist appearance. The enclosure is entirely aluminum, with two front displays on either side of the centrally mounted volume knob. The front plate is available in two colors--black or silver--with the rest of the enclosure in black. The unit is slim at only two inches high. It's also shallow, measuring a little over seven inches deep. Weighing only 10 pounds, the Okto is a lightweight. Sharing the same enclosure as the dac8 Pro--which can be rack mounted--means the stereo version can be used in the same manner. A single 1/4" headphone jack completes the front. A large assortment of digital inputs adorn the rear, including RJ45 ethernet, while two sets of balanced XLR outputs are present. The white-on-black OLED displays--which show volume, input, and bit rate and sample rate--are bright and clearly visible. An Apple Remote can be ordered, and controls the Okto as expected. Cycling through the menu is quick and responsive.
Sound
The Okto dac8 Stereo produced the highest SINAD score ever measured by Audio Science Review. If you are interested in reading details on the measurements, follow this link to the thread at ASR:
Okto dac8 Stereo Review
Objective measurements can give insight on how a dac will perform. We don’t listen to graphs, however, and subjective impressions can differ from measurements. R2R dacs, for example, frequently measure poorly compared to delta-sigma dacs. I had been using the Auralic Altair in my system for the previous three months. Its dac section is similar to the more expensive Auralic Vega, and uses an ESS 9018 chip. The Okto utilizes the ESS 9028PRO chip in comparison.
While comparing the two dacs, some volume matching was needed as levels were lower with the Okto in the chain. Interesting, considering both dacs have identical output voltages (my Okto has the standard 4Vrms, while custom voltages can be requested when ordering). The Okto also features seven digital filters. Switching between them made almost no difference. I did note the worst sounding was SRLP (slow roll-off, linear phase) which came across as overly bright. I selected the default FRMP (fast roll-off, minimum phase) filter during the comparison. The Altair was used with its default "Smooth" filter.
After adding the Okto in my system, I first noticed the sound was thinner and brighter. Highs had more sparkle and presence, a welcomed addition in my book as the Stax SR-007 can sound dark in some systems. The Okto has less midrange bloom, which tends to make the Altair sound warmer and more full-bodied. Bass is tighter and punches deeper on the Okto. More extensive listening revealed significantly higher resolution from the Okto. Micro-detailing is fantastic, allowing you to hear right down to the finest nuances. Timbre and dynamics are exemplary, producing a natural quality to the sound. Separation and imaging is better as well, giving greater dimension to the headstage. The Altair tends to impart added warmth, while the Okto presents the music with no coloration. Dead neutral and totally transparent. Nice!
Streaming
The Okto can be ordered with an internally mounted Raspberry Pi, which features both an RJ45 ethernet port and two USB-A inputs for using a WiFi dongle. A jumper is provided that connects one of the Raspberry Pi's USB outputs to one of the Okto's USB inputs. The Altair features Auralic's own Tesla G1 hardware platform--a quad-core processor with native Roon support. To compare with the Altair the Okto’s Raspberry Pi was loaded with RoPieee, which allowed both dacs to operate as Roon endpoints. A Cardas Clear USB cable connected the Altair to the Okto. Direct A-B testing was not seamless, as I had to change the input on the Okto and then select the correct zone in Roon. Performance between the two is very close if not identical. The Okto
maybe has a darker background, which translates as slightly higher resolution. A more upscale streamer might yield superior results, but to my ears in my system, there’s virtually no difference between the Okto's Raspberry Pi and the Altair's hardware.
The aspect where the Okto thumps the Altair is in usability. Even with the Okto turned off, its Raspberry Pi remains recognizable in Roon. This allows for almost instant music playback. Simply turn the Okto on with the Apple remote or volume knob, and you’re ready to go. Using the Altair is not as painless. After powering on the unit the display will read “starting…” Unfortunately the Altair will occasionally get stuck in a loop, and this message will display indefinitely. Toggling the power switch on the rear--or even unplugging the power cord altogether--is needed to reset the unit. The Altair also requires manual network configuration, something that can only be done using Auralic's proprietary software, Lightning DS. To add frustration, Lightning DS is only available for iOS devices. I do not have an iPad or iPhone, so to work around this I have to put the Altair into wireless access point mode and load Lightning DS in a web browser. Simply put the Raspberry Pi in the Okto is easier to use, responds quicker, and is more stable.
Final thoughts
Given its SOTA class-leading technical performance, superb sound, and relative low cost ($1500 as tested), I see the Okto as a tremendous value. Production has been quite slow, and lead times are exceeding four months at this point. If you can accept the long wait, you will be rewarded with a fantastic dac. I can’t imagine anyone would dislike the Okto, unless they are looking for a specific sound or coloration from their dac. The Auralic Altair was handily beaten and will be finding a new home. The Okto is here to stay.
