Home > DIY HiFi, USB AUDIO > Musiland MINI I2S to Buffalo II DAC

Musiland MINI I2S to Buffalo II DAC

Here is how I connected the Musiland I2S outputs to the Buffalo II DAC:

The twisted wire pairing to each signal wire are just ground wires to provide some noise immunity.

As it turned out, I had forgotten to solder the non-spdif pins and therefore I had no sound in my previous attempt. And even though I had modified the s/w for 24 bit I2S input and dissabled the automatic SPDIF detection feature, the current version of the s/w (v.05) should work.

The current software uses many startup default register configurations including auto-detect of SPDIF and 32 bit I2S; as such, the Buffalo II DAC can:

  • Automatically detect whether you have applied I2S, DSD or TTL-SPDIF signals in the pins (by looking at the bitclock and data rate) [link].
  • Automatically determine the bit-depth of the I2S signals

You must have a TTL-level SPDIF and bypass the comparator (SPDIF switch set to “OFF” or “1”) for this to work. If you pass the SPDIF signal through the comparator (SPDIF switch “ON” in the DAC), then I2S will not work because the comparator is also feeding pin D1, and even if there is no SPDIF signal, the comparator will hold Pin D1 low.

COMPARISON WITH SPDIF INPUT

I did not do any critical listening, but to me both interfaces sound the same. Surprisingly, however, the SPDIF interface apparently has less jitter; yes, LESS jitter.

With the SPDIF input, I had no problems using the lowest bandwidth for the DAC’s DPLL. With the I2S input, when using lowest bandwidth, I exprienced dropouts (the DAC loosing lock for a fraction of a sec and then regaining lock). I had to increase the bandwidth to “medium-low” in order to eliminate the problem. The Sabre DAC has adjustable DPLL bandwidth with 8 settings. So even though both SPDIF and I2S signals are generated in the same FPGA, the SPDIF signal is cleaner. This sort of contradicts the general notion of preferring I2S over SPDIF. There maybe other factors affecting the quality I2S in the Musiland implementation, but right now I can only point at increased jitter.

Update #1:

Coincidentally, two other users have experienced the same behavior in their USB->SPDIF/I2S converter boards: one board is the TPA USB board with the PCM 2707 chip and the other is the Teradak USB-SPDIF-I2S converter with Tenor 7022 chip (Teralink-X2)

Update #2:

There is something I don’t understand about how the Sabre DAC handles the I2S data. There could also be more to the way SPDIF is handled that ESS is not saying. For now, SPDIF allows setting the DPLL bandwidth to “lowest” which is the default setting of the Buffalo II DAC.

Because the lowest setting provides maximum jitter rejection, SPDIF is  the preferred interface with the Sabre32 DAC. For now don’t bother with I2S.

Below is a chart of transmitter jitter vs PLL bandwidth

Update #3:

Reader Rosendorfer posted a comment about using the HiFace USB-SPDIF converter.

Update #4:

There are reports about a problem with the I2S interface to the point that “a manufacturer takes the I2S input and converts it to SPDIF before sending the data is transmitted to the Sabre DAC“.

Reports of having problems with I2S/DSD interface into Sabre DAC:

  1. Hiface Evo [Link]
  2. TPA USB board based on the PCM2707 chip [Link]
  3. Musiland MINI, based on Spartan FPGA [This post]
  4. Teralink-X2 based on TENOR TE7022L and 1ppm TCXO [Link]
  5. AudioGD ESS DAC [Link]
  6. “Manufacturer X” converting I2S into SPDIF before feeding the DAC [Link]
  7. SDTrans192 [Link]
  8. ElectrArt USB Interface and SACD players: best DPLL bandwidth is medium-low [Link]

Reports of NOT having problems with I2S interface into Sabre DAC

  1. Hiface USB interface [Comment section in this post]
  2. SDTrans192 [Link]
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  1. Rosendorfer
    2010/12/21 at 18:45

    Hi GLT

    First let me say that Your blog is THE Best with info on Musiland and TP DAC’s… My best compliments…
    Well..
    If I may share my experience about I2S and BuffaloII as I do have bit different experience …
    I do use right now M2tech HiFace as USB2Spidf and I did, listening comparisons with PCFoobar@KS-> HiFace -> BuffaloII -> Legato -> HD650 and I prefer I2S over Spidf and this is quite clear difference..
    Of cause this is just my subjective humble opinion…
    And as for I2S “dropouts”…
    I do have now Dual Mono Buffalo configuration and I2S wired to 2 DAC and newer have any “dropouts” or any problem with HiFace@I2S and BuffaloII.

    But I know that Buffalo is extremely sensitive on “power supply”, And I have to put quite some ferrite beads on my power leads to stop “dropouts” when ie. fridge my soldering iron or some other home stuff turn on or off.

    Well just my 2 cents from my experiences…

    Best Regards
    Rosendorfer

  2. Hifiduino
    2010/12/22 at 00:38

    Hi Rosendorfer, thanks for your compliment and thanks for sharing. You have advanced a lot in your audio knowledge. Your experiments and measurements are very interesting indeed. When you start producing your own boards, I’d probably buy some from you :-)

    I’m glad you do not have dropouts with HiFace. The clocks in the HiFace are generated differently too and in theory much lower jitter since they are not generated in the DCMs as in the Musiland. So no mystery here.

    However, the real mystery is that with SPDIF, there is no dropouts, even though everything is from a single clock.

    I shall continue the investigation :-)

    Are you driving the HD650 with balanced or single ended?

    Merry Christmas to you and your familty

  3. Rosendorfer
    2010/12/22 at 18:56

    Hi Glt

    As for my Placid PCB I did start this like 2 months ago and no way going back…kind of next step into DIY fun…newer fought about selling….
    But it seems that Russ Tridents did take me by surprise, this guys are amazing…..

    And as for Spidf vs I2S I absolutely agree and know that @ HiFace this can be different than @Musiland and Your TTL Level Spidf @D1 into Buffalo definitely can be game change …..extremely nice mod.

    I bet that You will solve Buffalo SPIDF perfect reception mystery…My knowledge on this is close to zero, so I will hold myself with doing any speculation on this.. But out from my experience I would suggest that going with “less Jitter” Source into DAC is better that using “jittery devices” and relaying on ESS jitter suppression…ESS can be good in that, but is not going to deliver miracles….
    Well just again my 2 cents …

    Regarding my listening impression, I use Legato with HD650 in balanced connection. This is, as for now, my reference and I can only recommend this to try. Shortest and cleanest path from DAC into Headphones, just few transistors per channel…Going SE through LME opamp do change things a bit…

    All the Best for Christmas for You and Your Family …

    Rosendorfer

  4. Bunpei
    2010/12/26 at 15:17

    Hi, Rosendorfer,

    May I ask you a bit? Have you developed your own firmware for Buffalo II when you connected your HiFace to your Buffallo II or did you use original MCU embedded on Buffalo II without any modification?
    According to my understanding, the original Buffalo II firmware just set the DPLL Bandwidth parameter as NOT “the lowest” BUT “the best default”. When we set the parameter to “the best default”, we seldom experience the unstable-lock issue even for I2S input.

    Bunpei

    • Rosendorfer
      2010/12/29 at 16:21

      Dear Bumpei

      I can see that not only me is looking at GTL blog…:).
      Regarding HiFace@i2S and Buffalo as GLT pointed I do use just regular TP firware delivered with Buffalo…
      And I have heard that ESS NAD have been lifted lately so maybe they will share setings used there.
      I’m not sure if this can be relewant for Your case but I do use batteries for my HiFace Clocks…and presently I’m using GuidoTent Labs low Jitter Clocks for my HiFace..so this is not quite regular unit…;).
      I’m not sure how important is this case, but I still have my trustfull Musilland US with I2S mod, so with some free time I could test for any problems there.. If this would be interested for You…

      Rosendorfer

  5. Hifiduino
    2010/12/27 at 03:14

    Bunpei,
    I believe Rosendorfer is just using the stock buffalo firmware

  1. 2011/01/02 at 22:59

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