Hello @Magnus,
ls this new firmware publicly available ?
Thx, dp.
I donāt think its available yet, but should be soon.
Going to wait until they get them at either Amazon or Crutchfield, so I can try it out and return it if I donāt like it. I love the sound of my Marantz HD-DAC1 and want to ensure the S2 can at least match it sonically. Would be getting it just because of the MQA processing. If my HD-DAC1 did MQA, I would just keep the Marantz, but they stated they have no plans for any firmware for MQA.
Glad to hear everything is getting sorted. I really like this little boxā¦would hate to have to treat it as a āproblem deviceā.
Some small MQA hickups thatās under investigation (short drop-out at start of a tune when DAC is released, pause/play, jump in tune), but that seem to happen for foobar, Tidal desktop app and Roon so itās not a problem with Roon. But it only happens when DAC is claimed, so once normal MQA playback has started it seems to behave.
The hickups are apparently as its supposed to be, the DAC needs a number of MQA frames before it switches to MQA. Funny thing though, if I use Tidal desktop app and start a MQA tune, it works flawlessly (it starts with MQA directly without any PCM music before), but with a slight delay. In foobar I get some slight hickups, and in Roon I get big hickups (same DAC and bit-perfect obviously).
Can this be improved in Roon, you canāt have a āsimpleā app like Tidal desktop app behave better than Roon, can you? 
HmāI am not getting hiccups on start.
I know how MQA detection works, but it should be possible to get that right without creating audible defects. Roon is always going to pump a little bit of PCM silence before start, but that is supposed to be OK.
Can you outline some more specific steps for me to follow to hear this? Maybe itās more noticeable with certain content?
If I can reproduce this on the S2, Iāll compare to the other MQA stuff we have here and see if itās on par or if thereās a sign that this one could be improved.
I have tried in Tidal, Roon and foobar. Tidal works good when you start a tune, but if you pause/play then all apps behaves similar: a few seconds with music over PCM, and 1 or 2 short drop-outs during the PCM period before it switches to MQA.
In Roon, you get the pause/play behavior when starting a MQA tune as well (DAC is released).
You have other MQA dacs to compare to, is this behavior similar for all MQA DACs?
Ok, I got it to happen. Itās weird.
Neither the Meridian Explorer 2 nor the Mytek Brooklyn have this behavior. It can of course take a small amount of time to sync an MQA stream and show the blue light, sure, but it should be seamless from an audio perspective, and on the other devices it is.
I could guess at what we are doing differently from the TIDAL app, but Iām not sure we should change itāthere is value in the way we made those choices.
On those 2 dacs, does it play PCM during the transition, or are they quiet? Or is the only difference the small drop-outs?
Here is a typical start from a released DAC on an 48 khz MQA tune:
It starts playing like 1 seconds into the tune, and/or there is a small pause in music (like 0.1 seconds), then it continues to play 48 khz PCM for about 2 seconds before switching to MQA.
Ok, I figured out whatās going on.
Thereās two playback scenarios for MQA:
- Playing the original MQA bits from the file
- Playing the output of the software decoder in the TIDAL app (MQB)
When I play the MQA file raw, I get a blue light on the S2. When I play the output of the software decoder I get a purple light and an āMQBā indication.
The Pre Box S2 Digital seems to make clean transitions working with the software decoder output, but not when dealing with the original MQA source file.
Roon doesnāt decode MQA at all, so it always plays the MQA through directly. FooBar too. But TIDAL does the partial decode in software. Thatās where the critical difference is.
You can turn on āMQA Passthroughā mode in TIDALās settings and get hiccups from their app too.
So it seems like this DAC gets in trouble when itās syncing to MQA, but does fine with MQB.
One day we will decode MQA->MQB just like the TIDAL app, which will probably hide this problem.
Butābecause Brooklyn and Explorer2 are able to sync both MQA and MQB without artifacts, I think this DAC should be able to do the same. I think that part is an issue in the DAC.
Just to make it clear, is the main difference between the S2 DAC and the Brooklyn/Explorer2 the hiccup that happens for the S2 during the transition from PCM to MQA?
Yah. On the other devices that transition is surely happening too, but itās not creating audible artifacts.
Cheers, reported it to John, lets see if he can sort it out (he probably hates my guts by now) 
@brian , @Magnus ,
I experience same issues with Pro-Ject Box S2 DAC as you have experienced as well. I also get the issue often during playback of MQA songs via Roon.
Sadly, the only 3-4 files i have (so to eliminate streaming issues) are all MQA (352khz) from 2L site and one other ā¦ when i use LMS/squeezelite to play these files - i see no issues at all (and seems to me Blue MQA light goes up immediately) where as when streaming via Roon (with different material/48/96/192 usually) it goes at 48kHz then switches to higher (MQA fequency) and then i hear stutter.
I donāt know where to download more MQA files to test different āencodingsā but if any of you have pointers beyond 2L ā¦ I tried to buy an album on onkyomusic.com but itās not valid for purchases from Spain ā¦ so canāt help in āmore testingā
Net is - i am not 100% sure itās DAC only fault (could be) ā¦ but it could be that it is a combination of Roon and Pro-Ject S2 DAC that is just not working as itās supposed to be ā¦
In foobar, I also donāt get any transition phase if I play from the beginning, however if I pause/play or jump in the tune I get the same transition you get in Roon (and with the stutter). The stutter is because of the DAC, but John didnāt seem terrible interested in fixing it.
Iām pretty sure. The DAC is reacting badly on transitions from silence -> MQA. I can make bad behavior with this DAC and multiple pieces of software by creating that condition, but other DACs do not have any issue with it.
Roon plays a little bit of silence right when playback starts before the musicāthis is legal and reasonable. Not all players do thatābut that doesnāt make it a bug. There are good reasons for it on our end, and they are not going to change.
The stuttering seems to be a DAC issue, but when I open a MQA file in foobar and play, or use Tidal with MQA pass-through, they both make the DAC go directly to MQA instead of playing the transition phase. In foobar, it seems very instantaneous (its like it tells the DAC to go to MQA state before the music starts).
All behaves similar when pause/play or when jumping in the tune, but I think there is room for improvement for the way Roon starts playing an MQA (this is from a user end perspective, might be technical reasons not to).
Incidentally, the way foobar and Tidal works also hides the DAC stuttering when beginning to play, which is why it is easy to think this is a Roon issue.