GeerFab Audio D.BOB Digital Breakout Box and High-Res Audio Disc Extractor

The Sword in the Stone

Equipment report
Categories:
Multi-format disc players,
Digital-to-analog converters,
Music servers and computer audio
GeerFab Audio D.BOB Digital Breakout Box and High-Res Audio Disc Extractor

Most of the time a specialized solution to an audio enthusiast’s problem is not inexpensive; however, occasionally a device comes along that not only solves the problem but also does it in an elegant and cost-effective manner. Welcome to the GeerFab Audio D.BOB. This device promises to allow you to use the DAC of your choice with a Blu-Ray, SACD, CD, CDR, or virtually any recognized-by-your-player silver or golden disc. As long as your player has an HDMI output, which all current players do, the D.BOB allows you to connect its hi-res PCM and DSD64 audio stream to an external DAC. Your DAC merely needs to be equipped with either a SPDIF or TosLink digital input, and in the case of DSD64, it must accept DoP over coax. Given that the D.BOB costs right around $1000, you’re probably wondering what the “cost effective” part of this deal might be. It’s cost effective because you can use an inexpensive player, such as the 4K-capable Sony UBP-X700 ($198), and with the right DAC, achieve the same, and in some ways, greater  fidelity, flexibility, and access to your library of silver discs, be they SACDs, CDs, or Blu-ray, than you can get with a much-higher-priced, premium, one-box universal player, such as the Oppo BDP-205 (which now goes on the used market for about $3000). 

Technical Tour
When I described the D.BOB to a tech-savvy friend, the first thing he asked was, “What about HDCP?” HDCP stands for High bandwidth Digital Content Protection, which is written into SACDs and Blu-ray audio discs. It limits the SPDIF coax and TosLink outputs on an SACD or universal player to CD-quality 16/44.1 maximum output. However, the HDMI outputs on those players also carry the CD layer, analog audio, video content, and, most importantly, DSD64 and hi-res PCM.

The D.BOB takes the data from the HDMI cable, passes the video content (including menu settings) through its HDMI output, while extracting the stereo DSD64 or hi-res PCM (up to 24/192) and sends that data through the SPDIF coax and TosLink outputs to an external DAC for D/A conversion, all the while maintaining the HDCP. There’s a reason the D.BOB does not have USB or AES/EBU outputs—they do not support HDCP, and their inclusion as options would violate the SACD/Blu-ray Audio licensing regulations, making the D.BOB “illegal.”

The D.BOB moves the SACD’s DSD64 (extracted from HDMI) to both the SPDIF coax and TosLink outputs via the DoP protocol (DSD over PCM). Simply put, this involves packing DSD samples into a 24/176.4 stream that the external DAC unpacks, revealing the DSD. The result is DSD64 with no PCM artifacts.

Setup
Adding the D.BOB to your system is relatively simple. Since the D.BOB has no menus or other user-controlled configuration settings, you will be making any and all adjustments needed for optimizing the unit’s performance from your disc player’s menus, not from the D.BOB itself. 

My review signal chain began with the HDMI output from an Oppo BDP-93 Extreme ($1399 in 2011) connected to the D.BOB’s HDMI input. The D.BOB’s HDMI output was connected to my DVDO scaler/switcher, while the D.BOB’s RCA SPDIF and TosLink outputs were connected to my Mytek Manhattan II DAC/pre. With that, the physical hook-up was complete.

As I mentioned earlier, the only changes you will have to make to your system’s menus will be on your player. Most have the option of sending either a bitstream or a PCM digital output. Choose bitstream as your standard setting. There will also be an option on how to set the SACD output—DSD is the choice. The D.BOB is a stereo device, so choose the two-channel output option. 

Ergonomics
Using the D.BOB, once it’s set up and your player is properly configured, is as simple as operating your player normally and then choosing a different source on your preamplifier. Instead of selecting the disc player as the source, you would choose your DAC. On a DAC/pre’s inputs, you can use the D.BOB’s SPDIF or TosLink output. 

During the review there was one small glitch, one that has only been found to occur with the Mytek Manhattan II DAC/pre and no other DACs or DAC/pre’s—if you turn on the Manhattan II before the D.BOB, it may not synch properly. I have the Manhattan II, and this only happened to me once. 

Once the player was turned on and set up, I found the D.BOB’s operation was glitch-free. The only issue you might encounter is that if you’re playing a movie you may notice that the lip-synchronization is slightly off with some players, so you will probably prefer to use the machine’s conventional outputs with movies. 

Sound
What is the native intrinsic sound quality of the D.BOB? While the question seems simple, the answer is not. The final sound quality from the D.BOB will be determined not only by the quality of the D.BOB’s digital signal, but also by whatever is done prior to the D.BOB by your player’s digital audio circuits, as well as what happens to the signal after it leaves the D.BOB for your DAC or DAC/preamplifier.

So, there are a bunch of components in the signal chain that can have an effect on the final sound, which makes trying to ascertain what is integral to the D.BOB versus what is being added or subtracted by the other elements in the chain, extremely difficult, if not practically impossible, to determine. Since I’m not a terribly good guesser and trying out all the possible combinations of players and DACs that could be attached to the D.BOB would take up more time than I, or any other sane human, would be inclined to donate to such an undertaking, I did not attempt to connect the D.BOB to a large sampling of players and DACs.

The other difficulty in determining the D.BOB signal chain’s sound quality in my system was that the D.BOB’s SPDIF and the OPPO BDP-95 player’s analog and digital outputs all had slightly different output levels. While I could have tried to match the levels, it would have required a different (or additional) line-level preamplifier in the circuit with continuously variable and demarcated volume adjustments. The Mytek Manhattan’s stepped 0.5dB volume adjustments were not fine enough to match the levels critically. So, I did extended listening sessions without employing any rapid A/B switching.

The D.BOB is capable of handling up to 192/24 PCM and DSD 64, when attached to the Oppo BDP-93 Extreme. Once set up and running the sound was such that I preferred the sound from the D.BOB when playing SACDs to that of the analog output of the Oppo BDP-93 Extreme. While the difference was not night and day, the difference was pervasive and will be obvious, especially if it’s a disc you know well. The D.BOB signal was more incisive, with a greater sense of dimensionality and soundstage precision. Soundstage information was also easier for my ear-brain to process and decode through the D.BOB. On a good reference disc, such as the Blue Coast Collection—The E.S.E. Sessions, the differences were easy to detect. And if the D.BOB can best the BDP-93, which has a tweaked analog output section, imagine how much better its sonic performance should be than an inexpensive player’s two-channel analog outputs.

Summary 
The D.BOB is the first product that can extract DSD from SACD discs, as well as high-res PCM, for conversion with an outboard DAC. If you have a large collection of high-resolution discs, you want to have a future-proof way to continue to enjoy those discs into the foreseeable future. The D.BOB frees you from being tethered to one manufacturer’s, perhaps discontinued, disc player. You can use any manufacturer’s universal player with the D.BOB, so if that laser mechanism on your disc-spinner finally performs its last scan, you can replace the player with a modestly-priced alternative and get happily back to listening. 

The D.BOB fills a void that desperately needed filling. It not only simplifies source selection when playing higher-resolution discs, but also delivers consistently high-quality audio when attached to a current-generation DAC or DAC/preamplifier. While I don’t expect the price of Oppo BDP-205 to plummet soon, I do think that many prospective Oppo-chasers would be better served by a D.BOB coupled to one of the latest universal players from Sony, Marantz, Panasonic, or Pioneer. So, when that little ol’ Oppo dies, or you just want some insurance, the D.BOB could be an elegant addition to your digital playback system.

Specs & Pricing

HDMI compliance: HDMI 1.4b
HDCP compliance: HDCP 1.4
Input ports: HDMI Type A, Mini-USB (firmware updates)
Output ports: HDMI Type A, SPDIF coaxial audio (RCA), SPDIF optical audio (TosLink)
Dimensions: 8.5" x 1.75" x 4.75" 
Weight: 2.2 lbs.
Price: $999

GEERFAB AUDIO
173 West Bergen Drive
Fox Point, WI 53217
(414) 446-5841 
geerfabaudio.com