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How to make a streamer (Pro-Ject Stream Box S2 Ultra) playing Qobuz & Tidal to sound better than CD

Discussion in 'audio' started by duckworp, Jul 3, 2019.

  1. duckworp

    duckworp pfm Member

    The Pro-Ject Stream Box S2 Ultra is a very small £600 network bridge designed by John Westlake of Audiolab fame, and based on the Raspberry Pi. The Stream Box started off sounding worse than CD, but after some changes detailed below it ended up sounding better.

    The Stream Box has no internal storage nor an internal DAC. It connects to storage via two USB inputs and to an external DAC via a USB output. It streams via a Volumio software interface which connects to both Tidal and Qobuz and allows the use of a phone/tablet app to control the streaming. The Stream Box can be linked to a router via WiFi or Ethernet.

    The Test conditions
    I do not use hard drive storage so was only using the Stream Box S2 Ultra as a streamer for Qobuz/Tidal. For the following analysis and testing I was paying the Stream Box through a high-end DAC and comparing it to a high-end CD transport playing through the same DAC. I played CD resolution files from Qobuz and ensured that the Qobuz file that I was comparing was exactly the same file as the CD (ie there had to be no differences in the mastering which would make any comparison invalid).

    It is possible for me to do direct comparisons with the CD as it is possible to switch the input of the DAC from CD drive to USB at a flick of the remote control. I did not do blind nor double tests in case anyone asks, however I do trust my ears.

    The Improvements
    Each of the improvements below made small differences to the sound. When combined together they pushed the sound of Qobuz on the Stream Box to a sound better than the CD. It started off substantially worse than CD and ended up marginally better. Some of the improvements involve upgrading cables, which is a controversial subject which I don't think needs debating again here.

    What did it sound like out of the box?
    Qobuz sounded good but was noticeable poorer than CD. The sound of the Stream Box was a lot more grainy than CD, with notable harshness and a ‘digital edge’ to the sound. The music sounded flat with a reduced space and depth to the stereo image.

    Ethernet or Wireless?
    The Ethernet connection on the Stream Box sounded better than the WiFi connection. Hence all future listening was with Ethernet cable attached to the router.

    What changes were made to the Stream Box to make it sound better than CD?

    First let me say what did not make any difference:

    Changing the Power Supply from mains power to a Pro-Ject battery – no difference!
    I replaced the switch-mode power supply (smps) of the Stream Box with the Pro-Ject Accu Box S2. This is a battery powered power supply for Pro-Ject turntables and electronics. This made no perceivable difference!
    John Westlake, the Stream Box designer, is apparently a stickler for good sources of power and spent a lot of effort in making the smps for the Stream Box a clean source of power. He was obviously successful. I find that upgrading power supplies is often the surest way of improving the sound from some smps electronics. Not in this case.

    And what did make a difference to the sound?:

    Changing the settings in the Stream Box
    Two changes made a difference.
    - Turn the WiFi switch in settings OFF. This made an immediate and large improvement - possibly the biggest single improvement - and it is free! It means that the unit can no longer play via wifi nor connect directly to a phone. But the quality of the improvement was marked. You can still use a phone/tablet for streaming as that is via the Pro-Ject/Volumio app which connects from your router to the Stream Box via the ethernet link. So in reality there is no actual functional loss from turning the WiFi off in the Stream Box.
    - Turn the HDMI switch in the Stream Box to OFF. Again an improvement.

    Install a quality network Switch between the router and the Pro-Ject Stream Box
    By doing this you have an Ethernet feed from the Router to the Switch, which reclocks it, and sends a clean Ethernet feed to the Stream Box. A cheap switch (eg netgear) made no difference, but I found a second-hand Cisco switch (£50, though a few hundred new) was the one. With this installed there was a noticeable improvement. There are audio switches available but these run to hundreds of pounds and by all accounts are no better than the Cisco, which is known to be a very well-built network switch.

    Change the USB cable
    A friend of mine, an electronic engineer by trade, makes his own USB cables to a secret recipe and by using his cable it improved the sound over the others I had (the others ranged from a printer cable to a £300 cable – the printer cable and the £300 cable sounded identical!) My friend’s cable was only 12cm long and his theory is that a short cable does benefit the sound from USB.

    Change the Ethernet Cable
    I had Cat5 cable under all my floorboards wiring my house up. Unfortunately I found an improvement in using Cat 7 and then again Cat 8 between the router and the switch and especially between the switch and the Stream Box. I say unfortunately as it meant that I had to have the Cat8 running over the carpet and couldn’t utilise the hidden-away Cat 5. But the Sound Quality improvement was such as for this to be necessary.

    And with the above alterations the sound is now marginally better than CD.

    Comparison of the Pro-Ject Stream Box Ultra S2 to the Auralic Aries G1
    After configuring the system to the optimal sound as above I managed to hear an Auralic Aries G1 through the system to see if I could improve the sound further. This network bridge four times the price and has excellent reviews. There was no further improvement to the sound. Whilst the Auralic has a better interface via the Auralic Lightning app, the sound was no better, and if pushed I would say that the Pro-Ject may have had the edge.

    Comparison of Qobuz v Tidal through the Pro-Ject Stream Box Ultra S2
    Playing CD quality from Qobuz and Tidal resulted in a very close call but revealed Qobuz to be marginally better - a little more space in the music and Tidal had a slightly overbloated bass. When streaming hi-res Qobuz was a lot better but bear in mind my DAC does not unfold MQA.

    The Pro-Ject Stream Box Ultra S2 is a fabulous piece of kit and at a bargain price given its brilliant quality. Furthermore it is tiny. With changes to the settings, adding a network switch, and testing different cables it was possible to turn this streamer into a source as good as, if not better than, CD. And playing hi-res files produces a better SQ than CD.

    For more info on this rather amazing box I would suggest reading the Darko review or watch the Hans Beekhuyzen video review linked below. For network switches the best bet is a used Cisco 2960G or similar from ebay (£50).

    tuga and andrewd like this.
  2. SteveG

    SteveG pfm Member

    I'm really struggling to get beyond the "£600 for a Raspberry Pi with Volumio" bit to be honest - especially as Volumio is normally free and isn't the best anyway!

    It'd be interesting to do a comparison to my own Raspberry Pi based streamer (which has a DAC so bypasses all the USB output issues anyway, but could just as easily have been fitted with a digital output card instead of the DAC).
    Mynamemynaim, whatsnext and booja30 like this.
  3. webster

    webster Listen & enjoy.

    Very interesting and informative.
    I've been considering one of these for a while.
  4. duckworp

    duckworp pfm Member

    That would be interesting.
    Volumio is customised for the Stream Box by the way.

    Mr Westlake, the designer, explains here some of the differences between his Stream Box S2 Ultra and a normal Raspberry pi:

    here is an extract from His post:

    In answer to “why the extra cost” over the standard RPi3 – it’s required to give a basic explanation of the RPi3 weakness WRT high end audio applications (remember is designed as a lowest cost computer platform NOT a highend audio streamer). These weakness in no way are a criticism of the RPi3 – but rather its design limitation from my perspective as an audio designer.

    Basically its weakness are all based on Clock Phase Noise (Jitter) and local PSU noise (which directly impacts the Jitter performance) and also the resultant local RF emissions:-

    1. The USB HUB / LAN IC is clocked by the CM3 SoC which has significantly higher jitter then an external Clock oscillator. More detrimental is that fact that clock phase noise is heavily correlated with the SoC software processing – resulting in Data correlated jitter.

    2. The USB HUB / LAN IC PLL clock circuits are powered from the switching supply rail that also powers the SoC Memory, so as data is “processed” though the memory this causes modulation of the PSu Rail directly correlated with the Data patterns which then modulates the critical PLL in the USB HUB / LAN which is used as our USB “source” via this noisy PSU rail.

    3. As one would expect little care has been taken with the quality of the 5V rail for USB DAC power – in fact its really pretty poor by “Audio” standards.

    4. There are multiple “free running” switching regulators on the RPi PCB – whose clocks are not related to the USB clock Rate so there switching products are free to induced multiple / complex RF and Ground noise spurie in the system.

    I could list more weakness, but you can start to appreciate the “Deficiencies” (not unexpected) of the simple Rpi3.

    1. The little ProJect streamer tackles these issues by making the USB 24MHZ clock the system “Clock master” and cleanly generating the LAN’s 25MHz clock and the multiple local switching supply’s operating from a divided down synchronised frequency of this 24MHz.

    2. Great care has been taken with the internal PSU’s – I count 8 low noise PSU’s of the top of my head.

    3. The USB host signal from the CM3 is RF filtered and USB “Detoxed” (the poor Phase noise of the CM3 USB Host controller) is attenuated by two Cascoded USB Hub bridges (and RF filter) resulting in a much attenuated USB Jitter on the “DAC” USB output.

    4. The DAC 5V feed has a very low noise regulator – whose voltage and current can be monitored via the streamer software.

    5. The DAC 5V USB voltage output can be disabled via software for DAC’s that don’t require 5V.

    6. An external USB bypass to the DAC USB output is proved, this bypass “Detox’s” the external USB signal in the same manor as applied to the RPi CM3 USB Host output.

    7. 16GB onboard eMMC is available for OS / software & local files.

    Sadly, all this makes for an expensive hardware solution – with “low volume” production costs are factored (ProJect will manufacture thousands Pcs – not millions) – the end selling price is just a fact of European low volume manufacturing – this is not China manufactured mass market pricing…

    I don't seem to have an image of production versions of the PCB, but here's an early prototype of the board - where you can see its not simply a RPi3 in a smart box :)
    Dropbox - MiniStreamer A01 PCB.JPG
    Sorry for the errors in the published documentation / marketing – no text is run past me for proof reading…
  5. SteveG

    SteveG pfm Member

    The majority of those updates seem to relate to fixing issues with the Pi's USB output and there is an easier/cheaper way to avoid them - i.e. use something other than USB to connect to the DAC. In my Pi I'm using a DAC board (£40) but for a similar price could have used a board that had coax and optical digital outputs. Maybe if you really need to use USB then it's good value but it seems very expensive for what it does. If you added together what I paid for all 3 of my streamers (the Pi one, a Cambridge Audio Sonata NP30 and a Squeezebox Touch) and my preferred DAC (Simaudio Moon) it'd still only be about the same price as that Project.

    I'd need to sound really, really good to justify the price - and maybe it does (given I've never heard it)!
    whatsnext and booja30 like this.
  6. duckworp

    duckworp pfm Member

    My only comparison is with the Auralic Aries G1 bridge which is four time the price and it sounds as good (better even) that that one.
  7. daytona600

    daytona600 Registered User

  8. duckworp

    duckworp pfm Member

    Yes Pro-Ject are turning into a real force in audio electronics. I was thinking of getting their S2 DAC for my second system. Glad to hear it sounds good.
  9. The Bish

    The Bish pfm Member

    Are their higher end turntables well regarded? They don’t seem to get much mention on this forum.
  10. Del monaco

    Del monaco Del Monaco

    Excellent.My father in law has a higher range, 10 I think. A little blingy looking but very good sound.
  11. daytona600

    daytona600 Registered User

    Ulf Leiler likes this.
  12. simon g

    simon g Older, wiser & retired

    It's also worth considering the Lindemann Limetree Bridge or Network (difference is whether you need a built in DAC or not). I use one in to my Luxman D06U. A definite SQ step up than the same streamed track than using digital out from a Bluesound Node 2i. Having said that, the same piece of music played on a CD played on the Luxman is far superior, IMO.

    The Lindemann has a good app that's easy to use and responds very quickly.
  13. duckworp

    duckworp pfm Member

    If they are not playing though the same DAC it isn't really possible to compare CD transport vs Streamer. If they are playing through the same DAC maybe try some of the changes I applied to the Stream Box and see what happens? My CD started off way better than the Stream Box until I made the changes.
  14. simon g

    simon g Older, wiser & retired

    Well, there's the rub. It's exactly the same DAC; the one in the CD player (it has digital inputs), so a direct comparison is easy. I've now done this comparison 3 times with previous equipment, always using the same DAC (the one in the relevant CD player). Always the same result. I've posted elsewhere on this, but i may organise a small bake off for others to see what they think. It'd probably be mid/late September in East Sussex, if anyone might be interested?
  15. duckworp

    duckworp pfm Member

    Try turning the WiFi and other bits off in the network bridge/streamer, and try inserting a Cisco network switch between router and network bridge/streamer, and using Cat 8 Ethernet and messing around with the usb linking the network bridge/streamer to the DAC - all these helped make my network bridge/streamer move to CD quality.
  16. jan tomczak

    jan tomczak pfm Member

    done a similar thing...aries mini usb out to audionet vip g2 in...more open sound, more oomph...better sound but not by crazy margins. however playing a cd directly is still better imo, better depth of sound in vocals/instruments...a touch more precise/exact in it's timing, a touch wider soundstage... having said that i could easily live with just amp and streamer...great little box of fun!

    not tried fiddling with other ethernet cables/switches tho. mind you, purchased an album(cd) from soundkeeper recordings 'equinox' and sounds like a poor recording, a bit like covering my speakers with curtains, but when ripped on my laptop to 'musicbee' and connected via usb to my vip g2 the sound is a better like the curtains have been replaced with voiles. mad game this hifi
    lenticularis likes this.
  17. Dowser

    Dowser Learning to bodge again..

    Hehe - if a switch and network cable make an audible difference, I can sell you a very special catX cable which magically removes the need for any switch or hub between 2 important devices.

    Call it a passive step-through device. Or, if you’re a network engineer, a cross over cable... ;)
  18. Timo_F

    Timo_F pfm Member

    I follow this thread with great interest -- many thanks @duckworp for sharing your user experience with us.

    I have to admit -- when I heard about the Stream Box S2 Ultra for the first time, I nearly choked like others. 600 quid for a Raspberry Pi and Volumio??!! But I guess the proof of the pudding is in the listening... :)

    And the reviews for the little box are great... It appears that it sounds bloody good!

    But I am slightly concerned about Volumio, and more generally the software side. It has been a while when I had a chance to use Volumio. Admittedly, it wasn't for very long. But I felt it wasn't a good as others like iPeng or BubbleUpnp, for instance. Also, at that time, Qobuz didn't really work with Volumio. I love Quboz, and I wondered how Qobuz is integrated in Pro-ject's Volumio. For instance, does it offer different options for sorting albums, and does the search function properly? Whilst I liked iPeng, I never got along with their Qobuz integration -- sorting only by Date Added and a poor search function. Though this might have changed in the meantime...

    Many thanks!
  19. duckworp

    duckworp pfm Member

    You have identified the main issue with the Pro-Ject when streaming Qobuz. Search is actually fine with the Volumio-based software. But sorting favourited albums can only be done by date added, there seems no way to do it any other way which is frustrating. I contacted Pro-Ject who say they are working on a major update to the software so fingers crossed the update will integrate with Qobuz more intelligently.
    Ulf Leiler likes this.
  20. Timo_F

    Timo_F pfm Member

    Thanks for your feedback @duckworp - I really struggle to understand that it is so difficult to code a decent sorting function, and more generally a good integration of Qobuz. Maybe I should bite the bullet and go Roon...

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