Pro-Ject Pre Box S2 digital DAC

[atomic garden]

You're right! Didn't think I had to extract the driver and run it to look for the firmware; can't remember where it was before. I'm not even using this DAC anymore.

I still have the 2.12 firmware update if anyone needs it, though it doesn't fix this latest bug. Also the manual still doesn't mention John's recommendations on external power, and the separate DSD playback instructions are still out of date.

Hello left channel, could you please PM me your download link? If I remember correctly, you used to maintain a folder with the installers, FW, instructions etc.

And just out of curiosity, which DAC are you using now? Came back to Modi 2?

 

[left channel]

Sure @atomic garden, I'll PM the link to you.

I'm using my Modi 2U on my desktop, and experimenting with a NuPrime DAC-9 in my media room. I prefer their smooth AKM-based sound, though that's a subtle thing — their amplifiers are much more clearly different from Pro-Ject amps — and the main thing is I can enjoy my music without constantly checking for problems. I'm perfectly happy with software decoding or transcoding for the one or two formats those DACs don't support.

 

[atomic garden]

Thanks! I will post the results when the unit arrives here. Sometimes it's a nightmare to import something to my country.

Those 2 DACs you mention are very different price range. I imagine the DAC-9 sounds better, but lacking DSD512 is a show stopper for me.

Apart from the problems with S2, do you still prefer the sound of Modi 2U?

And for what I've being following, this bug with MQA content resetting the filter for non-MQA content is the only current known problem. Is there another one?

 

[left channel]

Thanks! I will post the results when the unit arrives here. Sometimes it's a nightmare to import something to my country.

Those 2 DACs you mention are very different price range. I imagine the DAC-9 sounds better, but lacking DSD512 is a show stopper for me.

Apart from the problems with S2, do you still prefer the sound of Modi 2U?

And for what I've being following, this bug with MQA content resetting the filter for non-MQA content is the only current known problem. Is there another one?

I only own DSD256 files and do no upsampling, so the NuPrime is fine for me and I find it a very good value for my big system. For the Modi on my desktop, I'm perfectly happy to transcode down to PCM 88.2, as I'm more likely to be wearing headphones there and often find the high frequency content in DSD unpleasant.

Hearing a clear difference between DACs can take a long time, much longer than amplifiers which are often an immediate "Wow!" or "Ouch". From the beginning I thought the Modi 2U sounded smoother than the Pre Box S2 Digital, but allowed that I might be experiencing some expectation bias. However after listening to both DACs for weeks on end, consciously and unconsciously, in the foreground and in the background, it became clear that I prefer circuits currently being designed around AKM chips. With the latest ESS chips everyone is designing analytical, cold, "reference" DACs that I find very unpleasant, but it seems that is the Pro-Ject "house sound". Everyone's ears are different, and interestingly some of that is cultural as well as personal, but there you have it.

Regardless, this product's MQA, DSD, and digital filtering features were more than making up for any such preference, especially as most of the sound is shaped by amps and cans/speakers, so I was happily inserting the Pre Box S2 Digital into my systems for a while. But now we have yet another bug, one that requires me to constantly monitor which mode the box is in, and Pro-Ject Support continues to respond like the non-technical marketing/PR staff they really are, with incomplete information or no response at all. I'm done.

 

[atomic garden]

Their customer care for sure is a big disappointment. The idea is to get the box running perfectly with no more bugs (maybe next firmware?) and don't need their support anymore, ever. A bit optimistic here, after all we are talking about an electronic device subject to failures any time.

For its features, design and price, the S2 Digital is a great deal for me, and I didn't even listen to it. I will be upsampling everything to DSD512 with HQPlayer (great upsampling software with a not so intuitive GUI) from Tidal via Roon.

Time will allow me to get to know DACs with other chips, so far I have only listened to ESS based DACs.

Based on your and other's opinion about it being analytical/reference, I also ordered a Magni 3. And one day later, the new Loki heheh. I think it will be fun

Anyway, great to see your continuum effort to help S2 owners on at least 4 forums I follow, even after this buzzkill. Thanks for that!

 

[pj.walczak]

From Pro-Ject FB site:
"Hello Pawel, the bug has been confirmed and we're working on a solution. Beta software is not for endconsumers, sorry. Once the final version is here we will announce it. Stay tuned."

 

[sberry20118]

From Pro-Ject FB site:
"Hello Pawel, the bug has been confirmed and we're working on a solution. Beta software is not for endconsumers, sorry. Once the final version is here we will announce it. Stay tuned."

This is positive news! Thanks for sharing this update.

Hopefully this is the final bug. It's the only bug left that I'm aware of, from reading across a few of the forums.

 

[pj.walczak]

I am still not sure about the power.
What is the optimal power for this box from design perspective when we are using USB input?
1. Use clean USB over USB Input (something like USBridge with good LPS)
2. Use dedicated LPS with PreBox (EXT) even when USB is connected (INT)?

And what is the difference? If we have both USB (INT) and USB power (EXT) connected to the box at the same time, is the box only using dedicated LPS (EXT), or is it powering some part of the board via USB (INT) and other parts of the board with dedicated LPS(EXT)?
We have analog stage power supply, we have power supply for clock circuity, we have powers supply for digital part, we have XMOS processor, we have FETs switching between INT and EXT. How those sections are powered up?

 

[MagnusH]

Since 2.12 this DAC has worked flawlessly for me, but then I don't use MQA which seems to be the remaining issue. And I prefer the more neutral and high detail sound from ESS compared to AKM chips.

The only thing I miss is a proper USB volume, where the volume change is done by the ESS chips and the display is updated when changing volume via USB. @JohnW do you have any update for this?

 

[left channel]

I am still not sure about the power.
What is the optimal power for this box from design perspective when we are using USB input?
1. Use clean USB over USB Input (something like USBridge with good LPS)
2. Use dedicated LPS with PreBox (EXT) even when USB is connected (INT)?

And what is the difference? If we have both USB (INT) and USB power (EXT) connected to the box at the same time, is the box only using dedicated LPS (EXT), or is it powering some part of the board via USB (INT) and other parts of the board with dedicated LPS(EXT)?
We have analog stage power supply, we have power supply for clock circuity, we have powers supply for digital part, we have XMOS processor, we have FETs switching between INT and EXT. How those sections are powered up?

I saw you also asked that question on their Facebook page. Good luck. The marketing guy who runs that page won't have an answer unless John tells him what to say.

John has previously stated here that when you plug in an external PSU, the device auto-switches away from USB power. I suspect it's still drawing a little USB power then anyway, even if just to detect the connection, but basically you are now on non-USB power.

All here who have tested these things agree that using an external PSU provides a larger improvement than adding a USB accessory to clean up the power and/or signal. In my case I heard roughly 90% improvement from external PSUs, and 10% improvement from an anti-jitter accessory. I tried removing the external PSU and supplying clean external power through that anti-jitter accessory, but heard no improvement.

John has also recommended that we use only linear or battery PSUs. I hear no difference between the stock switching wall-wart, a cheap linear wall-wart, and a smartphone battery pack. I would hope I'd hear a difference if I tried it with a linear PSU the same price as the DAC, but I am not planning to do further testing. (I have an UltraCap LPS-1.2 on order, but that is for my ultraRendu.)

 

[Jose V.]

I have found another problem: no sound coming out from whether coaxial nor optical input from my CD player. This is very strange. I checked with my previous dac, and it get the sound normally. The input signs lights up as sound would come in and frequency shows up in lcd screen, but no sound at all.
I also checked optical in from tv, and it works (it sound fantastic, better than the usb input)
What could this be????

 

[slavedata]

I saw you also asked that question on their Facebook page. Good luck. The marketing guy who runs that page won't have an answer unless John tells him what to say.

John has previously stated here that when you plug in an external PSU, the device auto-switches away from USB power. I suspect it's still drawing a little USB power then anyway, even if just to detect the connection, but basically you are now on non-USB power.

All here who have tested these things agree that using an external PSU provides a larger improvement than adding a USB accessory to clean up the power and/or signal. In my case I heard roughly 90% improvement from external PSUs, and 10% improvement from an anti-jitter accessory. I tried removing the external PSU and supplying clean external power through that anti-jitter accessory, but heard no improvement.

John has also recommended that we use only linear or battery PSUs. I hear no difference between the stock switching wall-wart, a cheap linear wall-wart, and a smartphone battery pack. I would hope I'd hear a difference if I tried it with a linear PSU the same price as the DAC, but I am not planning to do further testing. (I have an UltraCap LPS-1.2 on order, but that is for my ultraRendu.)

I have just finished building a linear power supply to supply both the DAC and a Pi 3 with Allo Digione coax connector. I used a kit off ebay from China based on a previously published amplifier power stage. Details below.
http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=121962363423
Based on this design
https://www.amb.org/audio/sigma22/

I used this transformer to give plenty of power and added heatsinks to the FETs
http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=112613323848

It sounds very good, very clean and quiet and not too expensive £60 all up.

 

[MagnusH]

Got my linear power now, China stuff but seems well built:
http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=263024207845

I notice a little stronger bass, and more details "behind" the music, if that makes any sense (small mid-range details). This is in comparison iFi iPower.

All in all, a nice cheap upgrade.

 

[left channel]

I have found another problem: no sound coming out from whether coaxial nor optical input from my CD player. This is very strange. I checked with my previous dac, and it get the sound normally. The input signs lights up as sound would come in and frequency shows up in lcd screen, but no sound at all.
I also checked optical in from tv, and it works (it sound fantastic, better than the usb input)
What could this be????

Sorry you're not getting an answer here, but it sounds like a unique combination that none of us would be able to reproduce. Across three different forums I've read many examples of people successfully feeding the Pre Box S2 Digital via coax and optical, though only from computers, streamers, and one TV. I'm feeding mine via coax right now from a Squeezebox Touch as an experiment, and it's working fine.

I can't recall anyone feeding it from a CD player, and at the moment I don't have a CD transport with digital outs (I'm waiting for the NuPrime CDT-8), so I can't try to reproduce your situation myself. But as I said, it sounds like a unique combination that none of us would be able to reproduce, and although the DAC may be operating within manufacturer's specs — or not — it clearly doesn't work for you, so if possible I would return it or auction it off.

 

[anthonyb]

Hi, I was feeding mine with USB, Coax and Optical (NUC, Pi, TV) and was switching between the three, no problems.

 

[anthonyb]

Linear PS from China, powering S2 and USBridge. I like it. I'm done spending money on my hifi (for) now.

 

[slavedata]

Trouble playing DSD files through the S2. Foobar2000 seems to have a vast range of options and I can't get a combination that works. I would appreciate an experienced user defining a set of options that work as a combination. I have upgraded the S2 to the latest firmware revision and I have installed to a Win10 machine driver 4.38.0.36018
The DSD files are downloaded samples from 2L.no I have installed the latest ASIO driver and the latest WASPI driver plus the latest sacd decoder ie foo_input_sacdfb2K-component.
So I think its just getting a combination that works together.
Many Thanks
Dave

 

[left channel]

Hi Dave, I believe foo_input_sacdfb2K is a nice-to-have, but what is essential is the foo_out_asio component.

Pro-Ject's instructions on computer configuration for DSD playback (PDF) were quite out-of-date last time I checked, but may still provide a useful structure as long as I note that (a) ASIOProxyInstall-0.6.5.exe is not included and not required, and (b) during preferences setup this product's driver will appear in a list of options and should be selected as your ASIO driver.

I haven't got the Pro-Ject attached to my Windows system at the moment, but I hope the above information is enough to help you start poking around in foobar2000 for a solution.

 

[slavedata]

Thanks cleared everything off started again with just foo_input_SACD & foo_out_asio. Now works fine.

 

[ajs6000]

Well I've spent the day playing HiRes formats through this DAC and can confirm the MQA bug. Also I found that when a DoP128 file stops playing you get a loud pop/click when the DAC switches back to PCM 352k (which it does automatically). When playing a DoP64 file there is no click when it switches back to PCM 176k. All my other formats played perfectly. I was using picoreplayer 3.22A running on an rpi2 with USB output. I used both the internal HP amp and an ifi ican pro.

Should I be reporting the 352k click/pop to pro-ject?