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Pro-Ject Pre Box S2 digital DAC

@JohnW,
firmware upgrade working perfect !!!!!!!!!!!!!!!!!!

No more clicks and DSD channels are correct.
Me VERY HAPPY :)
@MagnusH - thank you for help&sharing !!!
 
Good news all round then :)

I've thank Jarek for working so hard on the issue - the poor guy was in a real mess last week - it was such a frustrating fault, thankfully Dustin at ESS was able to shed some light on the issue...
 
Sorry to be bringer of bad news, but another issue popped up. Gahabana asked to try some MQA for a problem he discovered, and I had the same problem (I don't use MQA myself so I didn't try it until now).

The start of an MQA tune often does a pause 1-2 seconds into the tune, and occasionally it switches back to non-MQA during playback.

I only tested this in Roon, but since Roon sends bit-perfect data to the DAC I imagine it's a problem in the DAC.
 
Magnus,

Can you please try with Foobar as this is what we use to test the DAC's in the lab.

Hopefully we have not introduced a new issue with the latest software Beta.
 
Hmm, actually Tidal desktop app works. I don't have any local MQA music so can't test in foobar 2000. I'll check with Brian at Roon to see what he says.
 
Oh dear - seems Roon is not too happy ATM!

"and occasionally it switches back to non-MQA during playback" this suggest the Data is NOT bit accurate... I wonder if this is also related to the Roon DSD issue?

You can download MQA test files from here for local playback:-

http://www.2l.no/hires/index.html?

Note, sadly the source for all recordings is DXD so there's no true Native DSD verse MQA on this website :(

The odd thing is that Roon has certified the DAC - I wonder if with later firmware we have upset Roon playback somehow? Jarek and I was not involved with the Roon certification so we are totally in the blind here, to me its Crazy that the DAC designer's are not in the picture with such certifications!
 
When starting a MQA in Roon it does like a dropout about 2 seconds in, and that I can't reproduce in foobar or Tidal desktop app. But those apps seems to have a delay, so maybe they wait for the DAC to be ready before playing (if that's possible), or just wait a couple of seconds.

But if you press pause and play again, or jump forward in the tune, the DAC plays PCM a few seconds before turning on MQA, same behavior in foobar, Tidal and Roon. This made me believe that Roon has lost the MQA, but its just seems to take a few seconds before the DAC switches to MQA.

So basically, what seem to be the core of the problem is that the DAC plays a few seconds of non-MQA before switching to MQA if released when starting, and in that transition you can get a drop-out effect (the tunes goes quiet for like a second). This does not happen during normal play or if you let one tune end and another begin, but pause/play, jump in a tune or a fresh start of a tune causes it (I would guess whenever the DAC is released and claimed).

Maybe not a big OMG problem, but if its possible to solve it would definitely improve MQA playback. I don't have any other MQA DACs to compare to, maybe they all behave like this.
 
When starting a MQA in Roon it does like a dropout about 2 seconds in, and that I can't reproduce in foobar or Tidal desktop app. But those apps seems to have a delay, so maybe they wait for the DAC to be ready before playing (if that's possible), or just wait a couple of seconds.

But if you press pause and play again, or jump forward in the tune, the DAC plays PCM a few seconds before turning on MQA, same behavior in foobar, Tidal and Roon. This made me believe that Roon has lost the MQA, but its just seems to take a few seconds before the DAC switches to MQA.

So basically, what seem to be the core of the problem is that the DAC plays a few seconds of non-MQA before switching to MQA if released when starting, and in that transition you can get a drop-out effect (the tunes goes quiet for like a second). This does not happen during normal play or if you let one tune end and another begin, but pause/play, jump in a tune or a fresh start of a tune causes it (I would guess whenever the DAC is released and claimed).

Maybe not a big OMG problem, but if its possible to solve it would definitely improve MQA playback. I don't have any other MQA DACs to compare to, maybe they all behave like this.

Yes the initial delay to detect MQA decode is inherit part of the process with MQA decoders - the decoder needs "X" amount of vaild MQA encoded frames to switch to the full MQA decode.

There are few hardware MQA decoder DAC's on the market so I suspect its just that one is not accustomed to this behaviour.

With MQA dropping out partway though a track then this is indicative of non bit accurate data and the MQA decoder is not seeing valid data.

We have nothing to suggest its hardware related as MQA works with other media players we use.

Roon's having issues with DSD over PCM playback where again Bit accuracy is required, so I suspect Roon is having some buffering issue or some such that is causing problems that become apparent with MQA and DSD over PCB where a few missed cycles becomes apparent (you can drop a few cycles with PCM and its surprisingly inaudible).

Lets give Roon time to look into the issues - if its confirmed hardware related (which I don't suspect as other media players work as expected) then we will take a closer look.
 
Yes the initial delay to detect MQA decode is inherit part of the process with MQA decoders - the decoder needs "X" amount of vaild MQA encoded frames to switch to the full MQA decode.
Ok, the only minor issue is the slight drop-out then, which I can detect in foobar as well (just pause and play once), its not a big deal though (especially not for me that don't use MQA :) )

Since there is a sample rate switch when this happens, might this be related to the sample rate crack fix? For example, if you muted the DAC for sample rate switches, than this would work good for normal switch between tunes, but in MQA case it switches in the middle of the music and you get a small drop-out.
 
If the slight drop-out occurs as the DAC switches to MQA decode mode at the very start of the track then this is totally normal - you have to picture the audio path being switched over to the MQA decoding block.
 
As I said, I don't have any experience with MQA DACs so this might all be perfectly normal. The initial drop-out seems more severe in Roon though, and Tidal has managed to fix it completely, so I will ask Brian at Roon to see if it can be improved in Roon.
 
That's understandable - there are not many MQA DAC's with hardware decoders - even the AQ firefly relies on Tidal decoder - with just the rendering engine being done on the device itself due to the lack of hardware Mips.

I just wanted to clarify that the "drop-out" occurs at the start of the track / any play pause event, and not randomly during replay.
 
Hi John..S2 owner here...one other MQA issue I found. I cannot get the MQA logo to light up outputting TIDAL MQA files from my Bluesound Node 2 streamer. I followed instructions from Bluesound for external MQA dac to make sure it's a direct stream (fixed volume button checked, I checked the external mqa dac box, etc). I verified the tracks were mqa. I also contacted Bluesound.

Looking forward to the firmware update
 
It would appear that the Bluesound Node 2 streamer is not outputting bit accurate data...

If you have a PC to try via USB and reply a MQA file (again the PC needs to be set so that it outputs bit accurate data (no Volume control or up-sampling etc).

Foobar is simple and works well...

Sometime in the future (subject to Heinz agreement) we might offer a S2 series Pro-Ject streamer based on our MDAC2 streamer platform - we are able to stream MQA over this streamer link OK... The idea is a Plug&Play streamer solution for those who don't want to study for a computer science degree...

ANY streamer (or USB Host device) should work, the only requirement is bit accurate Data... the trouble is not many are bit accurate (especially at higher sampling rates), which is why we where forced to develop our own solution.
 
I just wanted to clarify that the "drop-out" occurs at the start of the track / any play pause event, and not randomly during replay.
Yes, sometimes there is even 2 drop-outs during the transition to MQA, one after about 1 second, and one right before the MQA logo lights up.

I have not experienced any drop-outs in the middle of play, its only in relation to start, jump in tune or pause/play. On a few occasions it has transitioned to MQA, then lost it and got back to MQA again (seen both in foobar and Roon). But generally speaking, once it's played for a few seconds it seems stable.

Btw, when I say drop-outs in this context what I mean is small periods of silence, probably like 0.1 seconds or so.
 
Brian tested this at Roon and compared to a couple of other MQA DACs (Explorer2 and Brooklyn), and neither of those DACs had any hiccups during the transition to MQA, but like the S2 they required a little time for the transition.

So the issue is the initial hiccup(s), before MQA starts. A somewhat sensitive issue, since a lot of buyers (and reviewers) will probably play an MQA tune as the first tune.
 
To be honest I REALLY dont care about a 100mS dropout at the start of a track - I don't think we can do much as MQA provide the Library...

I feel its getting too pedantic worrying about 100mS dropout at start of track...

So if it matters, maybe the DAC's not for you...!
 
Hey, don't shoot the messenger. For me it matters not at all, I don't use MQA, I'm just trying to help you fix the last issues and what you do with the information is up to you.

In my opinion, it's important for a DAC to be able to play music without disruptive hiccups. But I will let others speak for MQA (people who actually use it).
 


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