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.
Conclusion
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).
https://darko.audio/2019/03/have-your-pi-eat-it-pro-jects-stream-box-s2-ultra/
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.
Conclusion
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).
https://darko.audio/2019/03/have-your-pi-eat-it-pro-jects-stream-box-s2-ultra/