Stereophile Review

GeerFab Audio D.BOB digital breakout box

 

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This unique device is a solution to a problem that previously couldn't be solved.

There are, of course, any number of little boxes that can extract audio from the HDMI video bitstream; they began to appear on the market to fill a need for a way to route audio from a player's HDMI output In the recent past, you could buy a good-quality—even audiophile-grade—universal player and listen to SACDs via its good-sounding analog outputs. But good-sounding universal players are becoming scarce. People still want to play their discs, though, now and into the future, even after their current player fails, which of course it will do sooner or later.

As disc players have become fewer in number, they have also become less flexible. The market is dominated by mass-market "universal" players, and these have been shedding output options: Multichannel analog outputs have already disappeared, and stereo analog outputs are vanishing. Analog outputs that still exist usually use cheap DACs, and their output stages don't sound very good. Some disc players still have S/PDIF digital outputs, but SACD-licensing rules forbid any unencrypted digital output from DSD tracks, even if internally converted to PCM (footnote 1).

There are, of course, any number of little boxes that can extract audio from the HDMI video bitstream; they began to appear on the market to fill a need for a way to route audio from a player's HDMI output to older AV receivers (AVRs) that lacked HDMI inputs. Like cheap universal players, such boxes usually output analog audio via the cheapest, lowest-quality internal DACs and digital audio via S/PDIF, which does not support DSD because of content-protection rules for DSD and the copy-protection hurdles of the High-bandwidth Digital Content Protection system (HDCP), part of HDMI licensing.

Many universal players will output DSD over HDMI, the do-everything portal for users with HDMI-endowed AVRs and preamp-processors. However, for music-focused SACD fans who have no interest in AVRs, there was no way to extract DSD from the HDMI audio stream. Wouldn't it be nice if we could sidestep the problem and play our SACDs with the DAC of our choice? Enter GeerFab's D.BOB.

Is it legal?
The GeerFab Audio D.BOB (Digital BreakOut Box) extracts DSD from an HDMI input and outputs DoP (DSD-over-PCM) via either of its two S/PDIF connectors: one RCA and one TosLink. It can also extract and output stereo PCM signals.

Wisconsin-based GeerFab, which manufactures the D.BOB in China, asserts that their implementation is legal and compatible with HDMI 1.4b and HDCP 1.4. We're audio reviewers, not attorneys. GeerFab appears to be saying that while the D.BOB allows DSD data to be output to the DAC of your choice, that datastream is still copy-protected, so it's fine. You can play it—you just can't copy it. Consult your attorney if you want certainty—or just take your chances (footnote 2).

Out of the box and into the system
The D.BOB is a small black box with nothing but a power-indicating LED and a light-gray logo on the front. There are no controls. None are needed.

On the rear panel, we see an HDMI input, an HDMI output, and those two S/PDIF outputs. On the right is an inlet for an IEC AC cord, another for a (supplied) 12V DC power supply, a power switch, and a mini-USB jack for firmware updates. The 12V DC jack makes it possible to use a battery supply or a linear supply.

In operation, the HDMI output from your universal player (I used an Oppo UDP-105) goes to the D.BOB's input. The D.BOB's HDMI output can, if you wish, connect to your display or AVR so that you can access the player's setups and menus, but the HDMI output connection is optional. The S/PDIF output conveys stereo PCM up to 24/192 and stereo DSD as DoP to your DAC. DoP packs DSD into a PCM bitstream, identifiable as such by means of a flag; these days, most DACs are DoP-compatible.

It worked!
I loaded the Oppo with a recent SACD of pianist Romain Nosbaum playing a selection of "Saudades" by Spanish and Latin-American composers (SACD, ARS 38 287). It's a delightful hour of charming, witty music, played with panache and nicely recorded. I had been enjoying this recording in multichannel via a ripped file on my server; played in stereo direct from disc, via the D.BOB and my Mytek Brooklyn DAC, it lost a little ambience (relative to multichannel) and gained a little focus. When I compared the stereo DSD file with the D.BOB disc playback, there was little to choose between. With more complex music, such as the spritely and elegant Sextet Op.142 by Ferdinand Ries, performed by the Franz Ensemble (SACD, MDG 903 2136-6), the stereo-file-to-D.BOB comparison was still a draw.

I also made comparisons between the D.Bob's S/PDIF output and the direct connection from the Oppo to the Brooklyn with the same recordings, but since the Oppo (like other players) does not support DSD via its S/PDIF output, I was comparing the DSD tracks with the Redbook CD tracks. Even so, the differences were small once the levels were matched. I consistently felt that DSD via the D.Bob had more generous ambience and smoother treble. That's a sighted comparison leading to a subtle, subjective distinction, so I prefer the conclusion that DSD via the D.Bob was at least as good as direct CD playback and probably better.

With this box in your system, you'll probably also be using it to play audio from your CDs, DVDs, DVD-As and Blu-rays, too. I unearthed a few 24/96 and 24/192 stereo DVD-As, as well as a couple of CDs, and through the D.BOB, all of those PCM sources sounded fine.

Conclusions
Why didn't someone do this before? GeerFab's Eric Geer says it hasn't happened before because it's complicated. He had to solve three problems at once: extracting hi-rez audio, keeping HDCP copy protection intact, and outputting DoP over Coax and TosLink. It took him three years to solve it.

Some readers will have no use for the D.BOB. Some may find it expensive, at a shade under $1000. A few may be intimidated by lingering concerns over the legality of such a device.

Many, though, will pounce, knowing that the D.BOB can assure continued access, into the indefinite future, to the SACDs in their collection via the DAC of their choice. You know which group you're in.

 


Footnote 1: Meanwhile, higher-end players seem to be metamorphosing into streaming devices with DSD-compatible inputs—but those often leave out SACD disc capability.

Footnote 2: While it's true I'm not an attorney and so cannot offer legal advice, I've come to believe in the weeks since this article went to the printers that the legal risk, if any, is minimal.—Editor

COMPANY INFO
GeerFab Audio
173 West Bergen Dr.
Fox Point, WI 53217
(414) 446-5841
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