[Mihai IOV]

In MQA mode, all filters in the DAC's filter menu are disabled (except for the filters built into MQA, of course), and you like the sound of MQA. In other modes the filters work, and you don't like the sound of the Optimal Transient filter. Seems normal to me.

The Audio Quality menu has two options, "Best" and "Test". "Best" is the way John Westlake, the designer of this DAC, likes the sound: Distortion Compensation is disabled and the filter is Optimal Transient. In "Test", the settings are changed to match the best results from John's test lab instruments: Distortion Compensation is enabled and the filter is Brickwall.

You can also go into the menus to individually adjust everything, including several other filter options, after which Audio Quality will display "User". Distortion Compensation works in MQA mode, and I leave it on at all times. I'm not certain whether I like the Optimal Transient filter; I'll have to do some careful listening.

I understand and know very well all the things from your explanation, but the problem is not the sound of the filters, it is a possible problem in the software implementation/firmware.
The scenario which anyone can try to reproduce is the following: if you set the filter of the S2 to Optimal Transient (just for testing, no necessary for listening) and play a non-MQA song from Tidal, everything sounds ok. Then, try playing an MQA song and then try to play the same non-MQA song from the begining of the test. In my case, inside the S2 something is happening and the sound become thin and low volume. If I toggle the filter switch while playing that non-MQA song, the sound become normal. It's like the S2 remains stuck in some kind of MQA mode with MQA filtering.
I repeat, this scenario is valid only when using the Optimal Transient filter.

I'm writing about this problem because I think that can be helpful for somebody.

To solve this, I'm using another filter (although Pro-Ject recommends the Optimal Transient, which probably it's not the best).

 

[Left Channel]

I understand and know very well all the things from your explanation, but the problem is not the sound of the filters, it is a possible problem in the software implementation/firmware.
The scenario which anyone can try to reproduce is the following: if you set the filter of the S2 to Optimal Transient (just for testing, no necessary for listening) and play a non-MQA song from Tidal, everything sounds ok. Then, try playing an MQA song and then try to play the same non-MQA song from the begining of the test. In my case, inside the S2 something is happening and the sound become thin and low volume. If I toggle the filter switch while playing that non-MQA song, the sound become normal. It's like the S2 remains stuck in some kind of MQA mode with MQA filtering.
I repeat, this scenario is valid only when using the Optimal Transient filter.

I'm writing about this problem because I think that can be helpful for somebody.

To solve this, I'm using another filter (although Pro-Ject recommends the Optimal Transient, which probably it's not the best).

Thanks, I did not understand that the first time, my bad. I will test that. Perhaps we can try to get the developer's attention on pinkfishmedia. You said you are using the latest firmware. Is that 2.12? (To display the version, press Menu, down arrow, down arrow.)

 

[Mihai IOV]

Thanks, I did not understand that the first time, my bad. I will test that. Perhaps we can try to get the developer's attention on pinkfishmedia. You said you are using the latest firmware. Is that 2.12? (To display the version, press Menu, down arrow, down arrow.)

No problem, I thought it could be a problem with my explanation.

Yes, I'm using the latest drivers and firmware 2.12. The problem is obvious in both MacOS and Windows10, with both Audirvana and Tidal.

I'll share this finding also on pinkfishmedia maybe somebody else will find it useful.

 

[Left Channel]

No problem, I thought it could be a problem with my explanation.

Yes, I'm using the latest drivers and firmware 2.12. The problem is obvious in both MacOS and Windows10, with both Audirvana and Tidal.

I'll share this finding also on pinkfishmedia maybe somebody else will find it useful.

I hear the same thing, thanks! I've tested in the way you describe, with the Tidal app and foobar2000. I'm posting my results on pinkfishmedia [link] and hope John will find time to respond.

 

[Luk4s]

I understand and know very well all the things from your explanation, but the problem is not the sound of the filters, it is a possible problem in the software implementation/firmware.
The scenario which anyone can try to reproduce is the following: if you set the filter of the S2 to Optimal Transient (just for testing, no necessary for listening) and play a non-MQA song from Tidal, everything sounds ok. Then, try playing an MQA song and then try to play the same non-MQA song from the begining of the test. In my case, inside the S2 something is happening and the sound become thin and low volume. If I toggle the filter switch while playing that non-MQA song, the sound become normal. It's like the S2 remains stuck in some kind of MQA mode with MQA filtering.
I repeat, this scenario is valid only when using the Optimal Transient filter.

I'm writing about this problem because I think that can be helpful for somebody.

To solve this, I'm using another filter (although Pro-Ject recommends the Optimal Transient, which probably it's not the best).

Hi, I can confirm this. By the way the issue I had with playback has disappeared after the reboot.

 

[Left Channel]

Hi, I can confirm this. By the way the issue I had with playback has disappeared after the reboot.

Thanks for letting us know! About both issues.

I've tried to get the designer's attention on the filter bug. So far no response. I may also contact the Pro-Ject support manager.

 

[gto88]

@Left Channel thanks for follow up on this, it will benefit all owners here.

 

[Mihai IOV]

Hi, I can confirm this. By the way the issue I had with playback has disappeared after the reboot.

Indeed, the issue is solved by reboot but if you repeat the scenario it will happen again.

The only way, so far, to solve this is using any other filter but Optimal Transient. Also, if you don't listen to MQA files, the issue with this filter is not obvious.

 

[Left Channel]

Indeed, the issue is solved by reboot but if you repeat the scenario it will happen again.

The only way, so far, to solve this is using any other filter but Optimal Transient. Also, if you don't listen to MQA files, the issue with this filter is not obvious.

He had a different problem with playback before. It kind of got buried by our discussion without getting a reply, sorry. But now he's also discovered the filter bug.

To get attention for the filter bug, it would help if everyone will quote and reply to my pinkfishmedia post stating that you have encountered this problem too.

@Mihai IOV is already counted in my post, but if @Luk4s @gto88 and others do the same maybe we'll see a response.

 

[Charente]

Just quickly read through this thread ... thank-you for everyone's thoughts. I'm considering an S2 for office desktop role connected to an iMac (HiSierra) and I have a couple of questions. Has anyone any thoughts about using AEON Flow Open headphones (13 Ohm/95dB) with the S2 ? Also, is there any advantage to using an UpTone LPS-1 through USB via a pigtale power line (versus getting a DC-Jack/USB adaptor into the normal power inlet) ?

 

[Left Channel]

Just quickly read through this thread ... thank-you for everyone's thoughts. I'm considering an S2 for office desktop role connected to an iMac (HiSierra) and I have a couple of questions. Has anyone any thoughts about using AEON Flow Open headphones (13 Ohm/95dB) with the S2 ? Also, is there any advantage to using an UpTone LPS-1 through USB via a pigtale power line (versus getting a DC-Jack/USB adaptor into the normal power inlet) ?

I can answer your second question: it will perform better when powered through the external power jack. The designer of this product has confirmed this. He further recommends that with USB input we should use an external linear or battery power supply, rather than the included switching wall-wart.

Several of us here can confirm this as well. I heard the largest improvement from using an external PSU, and a very small additional improvement using an anti-jitter accessory on the USB line, but no improvement when sending clean power through that same USB accessory.

I'm using a cheap linear wall-wart with this DAC. But I do have an UpTone UltraCap on order to use with my ultraRendu, and that is why I can tell you this: the LPS-1 has been replaced by the LPS-1.2, shipping soon.

 

[Left Channel]

If anyone needs the 2.12 firmware update, PM me. The Pro-Ject support manager removed it from the product web page while they work on a fix for the post-MQA filter bug discussed above, but 2.12 still solves many other problems. Be sure to also update to the latest driver, especially if you use DSD playback. Last time I checked the driver update was still on the product web page (scroll down to just above the FAQs) but I also have it.

 

[Hifi-Junkie]

I've successfully connected the Pre Box S2 Digital to an Android phone and the UAPP app, via a UTG adapter cable. However, I needed to put my USB REGEN between them. My externally-powered Schiit Modi 2U connects fine with or without the USB REGEN, but the Pre Box needed the REGEN's help.

Power: My phone is a Pixel XL. When connected directly to the Pre Box I get the Android "USB Supplying Power to Attached Device" message, but the phone does not supply enough power and the Pre Box does not turn on. Powering the Pre Box with the supplied wall-wart didn't work either: the Pre Box powered on, but UAPP could not find it. But after disconnecting the wall-wart and inserting my USB REGEN, the Pre Box powered up and UAPP found it.

Play: I used UAPP to play several HDtracks hi-res files, and the Pre Box reported the sample rates perfectly. I then tried streaming from Tidal and Qobuz using UAPP, and found that unless I enabled bit-perfect in Settings anything above 44.1 kHz would stutter. I used UAPP to test Tidal HiFi, MQA, and Qobuz low + Hi-Res. Everything was detected and sounded as expected, with one minor exception that I suppose is due to the way MQA works: during MQA streaming, UAPP showed 48 kHz which is what it sees in the package it's sending, and the Pre Box displayed 192 kHz which is the result after unfolding in the DAC.

Success. Not a portable solution without a better power source, but interesting. I'm looking forward to seeing someone try this with an iPhone or iPad. I tried an Android tablet, a Pixel C, and couldn't even get the "USB Supplying Power to Attached Device" message, but I assume with the USB REGEN inline I would be able to do the same as above with my tablet.

And yes, I get the popping noise in this app too. Can't wait for the firmware update.

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Edit: clarified "my Schiit Modi" is "my externally-powered Schiit Modi 2U".

Hi there,

I just got my S2 yesterday and could directly connect to an Android TV box (Egreat A5) without any USB conditioners. Detected by UAPP. Maybe useful for the home setup. .

 

[Left Channel]

Hi there,

I just got my S2 yesterday and could directly connect to an Android TV box (Egreat A5) without any USB conditioners. Detected by UAPP. Maybe useful for the home setup. .

Thanks for that info. I suspect what helped in my case was not so much the signal cleanup as it was the power provided by the USB REGEN. The Android phone just doesn't supply as much power as the Android TV box, and may not even have power on one of the pins where the S2 expects to see it. Even when running on external power, the S2 probably needs to sense at least some power from the USB jack.

 

[Lionmax67]

Hi to All, I’m new on Head-Fi
I’m interested in Pro-Ject Pre Box S2 but before to buy it I need to understand how is possible to avoid to use it with a PC or an IMac; perhaps I need to describe better my situation: now I’ve an old Teac DAC that has to be connected through a long USB cable to my PC...disaster! Now I want to improve the performance with this new DAC but i want to connect it with a little player , streamer , or something else that can Manage all the features of this player (MQA and DSD player) - for example something like the Allo Sparky USB Bridge.... Please help me....