Heads up: dCS Rossini does not like the GeerFab D.Bob

I’m not sure who is at fault here, the D.Bob or the Rossini, but when connected about once per second for the briefest fraction of a second the Rossini will see the signal as 24/176.4 PCM rather than DSD as denoted by the front panel display, and will switch modes/filters; this will be accompanied by a “tick.”

This happens so quickly the only way I got a photo of the 24/176.4 screen was to take a video and grab a still shot of the frame showing the PCM signal.

This means at first listen the sound seems to be working, but when you get to a quiet portion or silence between tracks, it sounds like low-level static in the audio signal.

I tried both BNC and RCA S/PDIF with different cables, and it’s definitely something in the data stream.

Note this does not happen if I feed DoP from a computer, only via the D.Bob.

Interesting. Bill, are you clocking the Rossini? I had a problem with my DBOB at first until I set the Clock while using Toslink to the Audio setting.

Word clock from Rossini Clock.

S/PDIF via coax.

I would check to make sure you’ve got the Clock set to A when using SPDIF. If you do, then not sure what’s next.

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Nope, set to Word Clock.

If I have to use Audio I’d rather return the D.Bob as there’s no point in listening to the additional jitter.

Is your DSD upsampling set to DSD, or DXD?

Upsample is set to DSDx2.

Bill, Greg’s right, you’d have to set your Rossini DAC’s Sync Mode to “Audio” so that it can sync to the D.Bob’s incoming S/PDIF stream (as the D.Bob doesn’t have a Word clock input to sync to your Rossini Clock).

If you’re curious:

D.Bob to Rossini

That’s disappointing; other S/PDIF sources (computers connecting via S/PDIF, satellite receiver, etc.) don’t need to be put into Audio mode.

So am I confused here about the dCS philosophy on things?

Is it really a matter of if you are using word clocking the entire universe must be synced using word clock for it to work properly?

I would have thought the point was the DAC unit should buffer the received sample and feed it to the actual DAC at the rate locked to the external clock.

Certainly that’s the way PCM seems to work as, as I mentioned above, my satellite receiver and computer have no word clock input and work just fine with the S/PDIF inputs on the RP.

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This is not unique to dCS, every system that has synchronous connectivity (S/PDIF, AES, TOSLink etc), needs to be sync’ed to a single clock as these are real-time streams.

If you have multiple separate clocked streams, expect to experience problems. The fact that you haven’t experienced clock slips with your Satellite receiver is just pure luck. :grin:

Computer connectivity, USB or Ethernet, are asynchronous streams that are easily buffered, it’s non-real-time, so don’t suffer the same issue at all.

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To each their own, of course. For me, the DBOB affords easy playback of discs before ripping them or, as sometimes happens, when guests want to hear a disc. I don’t find the “less than perfect playback” offensive. I play discs so rarely that I cannot justify the price of a dCS transport. For me, the DBOB extends the functionality of my Oppo (a decent disc player), which is part of my home theater rig, and makes it useful for my speaker system. How will you play discs otherwise?

For Red Book, that’s why I got the Rossini Player rather than just the DAC.

For SACD, from rips via computer, as often as I play SACDs.

Whenever I get any new disc, the Red Book gets ripped into iTunes and SACD gets ripped before I even listen to it in a player.

I prefer to listen to disc, but to me any audio going through the Rossini Player that isn’t clocked by the Rossini Clock isn’t worth listening to at all, or I should have kept my Wadia S7i.

Without the clock the Rossini sounds distinctly substandard to what the Wadia could produce; only with the word clock did it exceed it. (to be fair without the clock it sounds like any number of other well-reviewed DACs I didn’t like like the Bartok, the Audio Research CD9 SE, the Ayre QX-5 Twenty, any of the MSB DACs, the Moon 780D v2 and the Mytek Manhattan - all great sounding DACs if you like the sound of harsh digital, not so much if you like the sound of pure music, IMHO - the very reason I only owned Wadia DACs from 1991 - 2020.)

Listening to the sound of the Rossini Player without the clock, I would never have purchased it, it’s that bad to my ears - no soundstage and vaguely metallic.

I often joke that dCS shouldn’t allow you to purchase the Rossini without the clock as a matter of principle. :slight_smile:

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Note that I use S/PDIF for not only the satellite receiver but also most PCM audio from my computer, including DoP, and it has never caused the RP to do what it is with the signal from the D.BOB.

As I mentioned above, the sound of the Rossini without the word clock isn’t even worth wasting my time with.

Understood. I get it Bill. This additional background makes sense. I’m a “file guy” myself, but I understand your preference and why the DBOB may not be acceptable in A mode.

Doesn’t make such configuration correct though. Guess you’re a lucky guy (or you never really notice slips before? :thinking: )

That said, the D.Bob’s S/PDIF output might be doing something particularly sensitive to the Rossini. I took a look at Stereophile’s measurement of D.Bob. I wonder if the following explain the issue you’re seeing;

If I’m not mistaken, those figures are well outside the threshold of S/PDIF’s (IEC60958-3) acceptable timing/jitter specification for similar signal bandwidth (0.25nanoseconds). So, if you’re not syncing the Rossini to the incoming D.Bob PCM stream, I’m guessing the two will be out of sync much more often than perhaps you might experience with your other devices.

Just for fun I hooked things up and did a quick comparison:

When set to “Audio” mode the soundstage was confined to within the speakers, but when set to Word Clock, despite the ticks the soundstage clearly extended beyond the speakers on both sides.

Also, in “Audio” mode the transients of horns was ever so slightly rolled off, where they regained their sparkle in Word Clock mode.

I truly never experience it with anything I send via PCM, whether satellite, PCM from my computer or even DoP sent over Toslink or Coaxial rather than USB (I did a lot of experimenting over about two hours to try and catch anything except via the D.Bob and never could.)

I also found no difference between the D.Bob and the Rossini using either Coaxial or Toslink, or with the Coaxial connected via BNC to S/PDIF 2 or via a BNC to RCA adapter to S/PDIF 1. (I told you I tried a lot. :grin:)

That settles it then, you’re a lucky guy with your other devices :smile: