Pro-Ject Pre Box S2 Digital

Ah i see. I’m on Mac OS…

This baffles me. I thought USB transport was almost always worse in sound quality than coax.

The MQA software library is handled inside the DAC, the XMOS is the part of the DAC that handles USB and is in itself like a small computer. Its the same no matter the computer OS.

John Westlake, the designer of this DAC, has said that USB is the best way to use this DAC due to reclocking not being available on coax (or something similar).

Good news, during my contact with great Allo support, I was testing DSD Native playback from Allo USBridge (DietPi) on Pro-Ject Box S2 Digital.
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You can download and test from here: https://github.com/sparky-sbc/sparky-test/tree/master/pro-ject-s2

I thought the XMOS handles it on most MQA DACs.

Yea, it does, but XMOS don’t handle the other inputs, so they would also need some processing power to be able to handle MQA.

MQA is not done “in hardware” as you often hear, its just a software library that needs processing power (i.e. a CPU and memory) to execute, so for an input to handle MQA it needs to send its digital stream through some part of the DAC that has processing power. For this DAC, only USB does that and thats why only USB can do MQA.

At least, that’s how I have understood it, but I am not a DAC hardware wiz so I could be wrong. Perhaps @John_Westlake could clarify this? If anyone knows, its him :slight_smile:

For Mac you would need a DAC driver to achieve native DSD512. I think there is no driver from Pro-Ject for Mac.

And by doing DoP instead of native DSD, you are limited to DSD256 due to max PCM rate 768kHz. DSD512 with DoP would require a DAC capable of 1536kHz PCM.

You can give Windows or Linux a shot. DSD512 really shines. You can install Windows 10 on your Mac with bootcamp. Or you can also get a very small miniPC (about $150) and use it as Roon Bridge or HQPlayer NAA, and stream DSD512 from your Mac to the mini PC.

I bought a fanless miniPC ($175) for that purpose with the following specs:

  • Intel Apollo Lake N3450 Quad Core
  • 4GB DDR3 1600MHz (there is a 8GB version available as well)
  • 64GB ROM (eMMC)
  • Gigabit Ethernet
  • 2.4/5.8 GHz Wifi
  • Bluetooth 4.0
  • 3x USB 3.0
  • Windows 10 Home / Linux Ubuntu (you can chose)

Thanks for the detailed explanations. I’m indeed planning to go the NUC route very soon for the sake of convenience.

“Q: Does the device support MQA over the coaxial or optical input?

A: No, in order to enable MQA playback via S/PDIF a hardware change would be necessary, this would cause the price to go much higher. MQA hardware decoding is only possible via the asynchronuous USB input of Pre Box S2 Digital. ”

http://www.box-designs.com/main.php?prod=preboxs2digital&cat=default&lang=en

Yeah. Again, this surprises me because I thoght USB was almost always inferior to COAX S/PDIF because of jitter, etc.

I’m not sure it’s easy to generalise all USB inputs of all DACs that way though (I wish it were). Depends on implementation, product to product. Too many variables involved. Maybe something for a separate thread though, perhaps.

I’ll give the other inputs a listen on this DAC, later this weekend.

So, I have finally been able to mostly sort out the mqa dropouts. I was still having them, even tho I had updated the firmware to 2.12.

I had the filter set to optimal transient. I read on the pinkfishmedia forum that switching that to fast rolloff and enabling distortion seemed to sort it out.

I tried it and there is a marked difference. The only album I have issues with now is the Kaleo album, even that is better. I’m kind of wondering that as this only 44.1, even on mqa, that it may not be optimally encoded. But Hotel California now plays, which is a blessing.

Hi bevan, which Kaleo album is that? Just wanted to see/hear if I can reproduce the issue too. Cheers

afaik they only have one: A/B

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Silly me. Thanks Dick. Will give it a listen.

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That is the one - I’m streaming it from Tidal

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@dabassgoesboomboom how does the S2 compare to the Hugo2? Obviously it’s not quite as good, but how much worse is it? Different coloring?

Hi Magnus

I’m super super impressed with the S2 DAC. I have borrowed an iFi iCAN SE headphone amp and this has elevated things for me, for headphones listening.

I’ve found using a linear PSU to power the S2 to make more of a difference now with the iFi iCAN SE (than the S2 DAC doing both DAC and headphone amp duties), and I have the iCAN SE also powered by linear PSU. I’m not a fan of the iFi iPower that comes with their headphone amp.

I also used the S2 DAC as a stand alone DAC in a 2-channel speaker system - just as impressive. I also noticed the difference the external linear PSU made, compared with just leaving it USB powered. My observation the other day about USB power was using the S2 DAC’s built in headphone amp.

Sure the Hugo2 has a little more transparency and detail and drives my headphones really well, all in one nice little box. And you pay to have all that in one single little box.

I’m not letting go of my Hugo2 but if my Hugo2 went missing tomorrow, would I be in a big rush to replace this S2 DAC + iCAN SE combination sitting on my desk, both powered by linear PSU’s? probably not :slight_smile: I could live with this for sure.

It sounds fun with just it’s stock power supply too - there’s no need to go over the top the way I’m playing with it now but the linear PSU’s do make a difference to my ears now, depending on how the unit is used in a system. Fortunately well built linear PSU’s are quite affordable now as per earlier links in this thread.

And all of that is while I’m still yet to play with Roon DSP. There’s up-sampling and cross-feed (for headphones) to still play with ! I don’t feel any need to touch EQ, just as with my Hugo2 - everything is nicely balanced sounding with the S2 DAC.

I love great performing and high value for the dollar products and this S2 DAC certainly ticks all the right boxes.

Their entire S2 lineup is looking fantastic.

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Hi Sean, thanks for the feedback. which linear PSU did you use?

I’ve tried streaming this via Tidal, and I get a stuttering when I start playing, but after the initial few seconds it seems fine. It’s almost like it’s struggling to lock onto the stream.

Having said that it just stuttered mid track :roll_eyes: