Folks, we were able to catch our Skin the skunk lady for a short iDSD Pro related Q&A session.
Who knows? Maybe in the future she'll be able to give us even more insight about the product itself? In the meantime, here goes...
- Us: People ask how we do USB galvanic isolation on the Pro. Is it the same as iGalvanic? A trickle-down perhaps?
Skin: No, in the iDSD pro we operate very differently. We use a suitable isolation barrier between the digital (noisy) section with XMOS, WiFi/networking, the Chrysopeia FPGA and the DAC's / Reclocking / Clock. In essence, all noisy digital processing is confined to a blocked of "island" on it's own board and isolated from all audio circuitry.
This parallels the way in which i.e. the JVC K2 system is implemented for playback and the isolation of the DAC from digital noise found in the legendary Marantz CD/DA-12 system featuring the TDA1541. All this is essentially trickle-down from the DP-777.
The iGalvanic isolates the USB connection instead, so it is a less complete solution which can't isolate noise inside the DAC itself.
- Us: And what clocks do we use?
Skin: We use the same proprietary GMT clock system as originally developed for the AMR DP-777. Please see here to know more:
http://www.amr-audio.co.uk/html/dp777_individual.html
- Us: Are there digital outputs on the Pro?
Skin: No, what would be the point? This device was designed as a d/a converter above all else.
- Us: What is the RJ-45 output for?
Skin: It is not an output, it is a connection to your local area network (LAN). For reliable streaming, especially for high resolution audio wireless networking can be frustrating with dropouts and glitches.
If streaming hi-res content from a NAS or a server on your home network, a hard-line network connection is preferred over WiFi.
- Us: Does the iDSD Pro use an OCXO clock?
Skin: No, baking a crystal merely reduces long term thermal drift (over periods of minutes to hours) which is inconsequential to audio playback. We employ a high quality miniaturized 10MHz discrete crystal (not canned oscillator) as timebase for our GMT clock system.
The GMT clock system allows the clock frequency to be set with appx. 0.01ppm (parts per million) or better than 0.5Hz accuracy compared to the nominal 45/49MHz audio clock frequencies
- Us: At this price and by your earlier comments about USB (and SPDIF) inputs being impervious to upstream tweaks & add ons, that the PRO iDSD contains ALL of the micro iUSB3.0 and iGalvanic3.0 and SPDIF iPurifier tech, all built in?
Skin: Items like the iUSB or iG are "add-ons" for DAC's that due to cost constraints or other reasons benefit from such add-ons. But they are ideally avoided in the design stage if increased cost and complexity is not objectionable.
If one designs from scratch, a DAC without having much in terms of constraints placed upon the design, it is possible to achieve equal or better performance by design.
This is what has been done in the iDSD Pro. The solutions chosen are radically different from those used in iUSB 3.0 and iG 3.0 and are integrated in the design of the iDSD Pro much deeper than would have been the case by just adding the tech from other products.
Skin: Yup, anytime, but not too often as I have things to do!