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Igor Levin: "I asked Georgi to put together a document that compares the units and talks a bit about DSD upsampling. It is this latter feature that's extremely unique to us and to my knowledge the first time to appear in an audiophile D/A converter. I believe it to be crucial for significantly raising the bar on quality and performance of DSD playback. I remain open to comment on various nuances of the upsampling technology we offer so if you would like more clarification—subject to keeping our IP protected—drop me a note." About the drop of 768kHz USB: "The feature was originally proposed to play quad-speed DSD (x256) but our research showed that such files aren't easily available. Adding 768kHz also caused issues with device drivers and otherwise complicated the user experience. Since 256 is available already with our upsampling technology, we decided it was better to keep 768kHz out."

Georgi Lazarov: "The next-gen Voltikus is only compatible with the Zodiac Platinum. Both devices will come to market only as a bundle. One won't be able to buy them separately. The reason the new Voltikus is incompatible with the older Zodiacs is connectivity. The new Voltikus comes with a better cable and more robust connectors as our customers requested. The Platinum is our first DSD converter and our next step into high-end audio not just by providing DSD playback but by enhancing features and upgrading components in response to user feedback. What differentiates it from other DSD converters is that it really converts DSD files without prior conversion to PCM. Yet it not only converts but upsamples both DSD64 and DSD128 to quad DSD.

Zodiac Gold in black finish

"We do that because traditional 1-bit DSD DACs suffer a sharp build-up of out-of-band noise. This noise is the result of using 1-bit Sigma Delta DACs and intrinsic to the DSD process. This ultrasonic noise is so strong as to easily overload sensitive analog amplifiers into distortion. Hence DSD's HF noise is typically filtered with sharp analog filters set to between 30-50kHz. Unfortunately these filters introduce phase nonlinearities in the audible band and slow down transients to defeat most of DSD's benefits. Fortunately there's a way to reduce this build-up of out-of-band noise and the damage of the noise filters. The rate of noise build-up relates to the order of modulators used which relates to the oversampling ratio. 64 x oversampling in traditional DSD requires 5th-order modulators to generate rapid noise build-up. The Platinum upsamples 256 x and uses much gentler 3rd-order modulators. Hence we can use gentler noise-reduction filters to realize the true potential of DSD. For PCM we have implemented custom off-chip upsampling."

"High-quality upsampling of digital audio samples is critical to good sound. By smoothly fitting up to 8 points between two audio samples the technique makes reconstruction of the audio wave significantly easier and more precise. The quality of this process depends on the quality of the upsampling filters built into the actual DAC chips. The performance of on-chip filters is inevitably compromised by power and die-size constraints. Hence the filters themselves generate interference for the chip's analog part. The Platinum turns off and bypasses all on-chip filters to perform upsampling in a custom-coded FPGA instead. By separating the filters and implementing custom 64-bit precision—instead of the 28-32 bits typically used with on-chip filters—we exploit far superior upsampling to avoid interference with the DAC's analog functions. The result is more natural analog sound with very precise stereo imaging.

10M Rubidium clock

"With the new 10M input the advantages of our professional 10M atomic clock are available to home users. Whilst the Gold needed a master clock to connect to the DAC and then a 10M, you can now connect a 10M directly to the Platinum and enjoy a further improvement of sound quality, stereo placement and imaging. We also changed the converter architecture to quad DACs, i.e. two per channel working in parallel. Left/right channels are implemented in separate chips to eliminate crosstalk. Benefits are superior dynamic range and linearity for an enhanced stereo image. The Platinum retains the stepped relay attenuator but gets faster much quieter relays. Left/right channels no longer share the same relay. The benefits are quieter smoother switching between volume steps with even better stereo imaging. The same volume control now also runs the headphone outputs to lift the Platinum's quality as headphone amp. It even allows control of headphone volume from the machined metal remote which now enjoys a wider control angle; or from the software control panel.

"Unlike the Gold where output levels had to be trimmed with a screwdriver and input levels were preset, the Platinum allows full adjustment of the i/o levels via our easy-to-use control panel. Internal relays and precision resistors carry out these adjustments. Now this system calibration is a breeze and avoids the inconvenience and risks of manual calibration with its need for proper electronic instrumentation. With the Gold the external triple-regulated Voltikus was optional. With the Platinum we decided that moving up in the high-end environment should not allow compromises to make Voltikus part of the package. We did not stop there but went to a second-generation PSU with separated power line filter on board, improved transformer shielding and a better connector with stronger lock. A new high-performance power cord and a new precision-machined coaxial power umbilical are included. The stability and noise performance of the new Voltikus creates the foundation upon which the Platinum performance is built. The volume control knob looks much like the Gold's but has a much nicer feel due to a tighter encoder. Plus there are the forthcoming iOS and Android mobile apps to control our software panel remotely."

Zodiac Gold in clear-anodized finish

Snippets from Igor's LiveStream interview: "Higher sample rates are pure math. Higher upsampling to infinity gets you closer and closer to the holy grail of analog. This works for both post production and playback. Many plug-ins like compressors also work better at higher sample rates. On the Voltikus we approached it like a phantom or mic-pre PSU for ultimately low noise. On strategic dither and 64-bit clock modulation think of using black and white dots in a newspaper to create grey values for smoother transitions. You might call it the randomization of latent jitter. It sounds smoother. On atomic clocks try to improve standard crystal oscillators. You go to oven-controlled oscillators which control operational temps to within 1/10th a degree. That's our DACs. To go further means a Rubidium clock. Other atomic solutions like Cesium get prohibitively expensive. On our 64-channel USB driver for 32-i/o pro gear, it was designed for/with USB 2.0 and meant our very own USB chip. On our operational model, I began as a film director and team leader of writers, cinematographers, producers and actors. Antelope is a large firm with departments for mechanical engineers, graphic designers, analog/digital hardware engineers and software engineers who write embedded code and Windows/OSX drivers. I'm their conductor. I come up with an overall game plan and think of problems to solve. Then I have a lot of internal help."

On DSD/PCM filters, "we have chosen to fix them so they're not user selectable. Here we went for linear-phase filters. That makes the Platinum easy to use. It doesn't confuse or intimidate our customers with unnecessary options. Of course we do have the best Internet-based upgrade system in the industry should such requests come in. With the Platinum you can already decide to engage our upsamplers or not."

To recap, the operative math for the Platinum DAC goes beyond Gold + DSD by way of superior analog volume in 1dB steps for both main outputs and now also the two 6.3mm headphone sockets; new software-controlled analog-domain precision gain matching for both inputs and outputs; paralleled stereo DACs per channel; an improved PSU; improved IR reception; and enhanced UI features.