Despite very upscale positioning which lives far beyond curmudgeonly hairshirt appeal, Gryphon are true purists. Be it their non-feedback dual-mono fully balanced class A circuits or time-aligned minimum-phase loudspeakers, they'll talk shop with the most diehard audiophile extremists. It's this uncommon combination—of large-scale commercial success wrapped in slick presentation and professionalism still backed by that quintessential single-guy-in-a-garage fanatism—that's at the very heart of the Gryphon legend. To wit, the dual mono, no negative feedback declaration right below the model name on the Kalliope's business end. The absence of Toslink becomes further underwriter's guarantee of purism. So does the exclusive use of the superior 75Ω BNC format for all three galvanically isolated S/PDIF inputs (as well as the word clock i/o). An unexpected nicety is the 110Ω AES/EBU digital output. It forwards a dejittered version of inputs 1-4 (though not USB) to an external digital processor*. Two 12V trigger ports for whole-system integration, a ground post and RCA/XLR outputs complete the picture.

* "The reason that the AES/EBU digital output can’t pass signal from the USB input is that the USB I² interface also carries the DSD signal which is not covered in the AES/EBU standard. Relative to optional modules, at the moment there are none for the Kalliope but a future option could be an AVB module or perhaps an HDMI audio module."

Not apparent to the eye, behind that de rigueur asynchronous USB 2.0 port sits a virtual battery 12.5F Supercap supply to relieve the computer's 5V buss power. It handles up to 32/384 PCM and DSD512. For user menu adjustments, there are slow/fast PCM filters and 50/60/70kHz DSD filters; upsampling off or on to 210kHz; phase inversion; time to standby (30-min default, 1/2/4 hours or infinite); word clock sync on/off; output adjust (0dB default, -6dB on); DSD 1st-order low-pass filter on/off; 5-stage display brightness; 8-character alphanumeric input naming; restore settings to factory default. Being a dual mono circuit on four-layer boards with 70µm copper traces, there's one 65VA toroidal power transformer per channel. Converter silicon of choice is one Sabre ES9018 8-channel chip per channel configured for dual-differential coupling.

The touch-screen display will confirm the incoming sample rate unless Kalliope's own upsampler is engaged. In that case, the display will read FS: 210kHz. Charging of the USB Supercap supply is confirmed by a blinking blue LED. For full details, download the owner's manual.

To learn a bit about the gestation of Gryphon's first USB-enabled outboard DAC, I asked R&D project leader Tom S. Møller for some developmental background. "At Gryphon, we never were adopters of technology for technology's sake. We always find technology intriguing and follow it closely yet many of our experiments remain in the lab until the time is right. Gryphon made their first appearance 30 years ago with a revolutionary headamp. This took moving-coil amplification to a whole new level. Today this product remains a very much sought-after Gryphon, fetching sky-high prices not only for its collectability but, remarkably, for still being a stellar performer 30 years later. With its list of all-star topologies such as fully discrete circuits, super dual mono, ultra-high bandwidth, no negative feedback and more, most designers would still call its topologies superior but also expensive and hard to realize. These choices weren't based on bragging rights. These technologies simply provided the musical performance that to us was more important than anything else.

"The development of this product would start a Gryphon tradition that is not widely known. We started exploring whether there existed parts outside traditional choices; or traditional choices that would surrender better performance when used in unconventional ways not described or perhaps even imagined by the part's actual maker. When we decided to enter digital with our Gryphon CDP 1, we did so much later than many other manufacturers. The price which the consumer paid at that point was an investment in technology which moved so fast that it would render that product obsolete and worthless in a short time. Perhaps that's acceptable for low-cost products but it isn't acceptable to us or our policy of providing ultra-high end products with sustainable value. Another and perhaps more important reason for not trying to be first in digital was that the software for the most part was far behind the hardware. Good recordings were hard to find. We were experimenting with parts and found a 'back door' in the PMD-100 HDCD decoder and digital filter. This allowed us to follow a different path. The CDP 1's AKM chips were stereo converters but by using a pair of them, we could not only make a typical Gryphon dual-mono circuit but perform conversion in balanced mode. We also implemented upsampling and created the world’s first upsampling CD player as a technology that, until then, was something only found in very expensive standalone D/A converters."

Gryphon's resident listening room.

"The much more sophisticated Kalliope is the result of the same thinking and curiosity. They would lead us to follow alternative paths of implementing parts. At the same time we wanted to create a D/A converter with as much future potential as possible. Again we searched and found an alternate way to use the ES9018. Instead of traditional I/V conversion on the ES9018 current outputs, we use a refined high-speed discrete pure voltage amplifier based on our experience with discrete analog circuits. This allowed us to develop the analog section which this sophisticated converter deserves. Before choosing the ES9018, we put a lot of effort into listening to several other converters from the likes of Asahi Kasei and Analog Devices. In our CD players, from the CDP 1 on up to the Mikado Signature, we have used converters from AKM. At the time, we found those superior. However, comparing the sound quality from the different converters in our test setup now had us select the Sabre ES9018 32-bit converter for the Kalliope. By choosing the ES9018 programmable D/A converter, we also opened up the option of future software upgrades featuring custom digital filters.

"One of our core beliefs is to keep signal paths as short as possible and to not risk vital sound quality by converting PCM to DSD and vice versa. The ES9018 handles both PCM/DXD and DSD512. Our minimum-jitter asynchronous USB module supports 32/384 PCM and DSD512. For it we developed a unique power supply with a 12.5F SuperCap which, when fully charged, acts like a true battery supply. This approach really elevated the sound quality from USB. Like our Mikado and Mikado Signature CD players, the Kalliope is built with modular digital sections for possible future upgrades. An empty module slot inside leaves space for a future digital module like AVB audio over Ethernet. For analog, we went all out running pure Class A, no negative feedback and no capacitors in the signal path. The power supplies for the analog section are massive, with one toroidal transformer and 34.000µF power capacitor banks for each channel. Ultra-low noise +/- 25VDC regulated voltage supplies feature only top-notch components and comprehensive noise regulation on all digital circuits. All this R&D was fun and a lot of technical challenges had to be overcome. We achieved really impressive figures but overall, the real acid test was always whether we felt that it sounded 'right'. Again we learnt that there could be great differences between decent recordings, especially DSD files. However, great recordings shone and we never fell into the trap of using any 'makeup' or romantic 'hue' to cover up anything. We went for what we consider neutral because in our book, neutral is musical."