Total Distortion on Upsample above 384 kHz, DSD 256 Works Perfectly

Hi @Grant_Munday,

Is the behavior the same here if you do not use “power-of-two” and just regular upsampling instead?

This would be our next step here, since we would have another data point. Seems to be the trend that even on iOS there are issues so this would either be related to the Core or to the DAC itself. If you are able to temporarily host the Roon Core on the other PC (not in remote mode but in Core mode), it would provide some more info in which direction we should search.

– Noris

If I do not use power-of-two, and use max PCM rate, there is a way i can “lock” it in. So, if i select a song that is in a 48 multiplier and turn dsp off then on again while the song is still playing the distortion will go away, locking in 768, and I can select other songs with 44.1 and also no distortion. However, if I have any MQA rendering on, and go back to a regular PCM file, the distortion will come back. But, if I only have Roon core decoding on and play MQA files without the rendering and it plays at 768 they also play without any problem. Rather odd, but I have discovered it while spending some time fiddling around with the settings.


I was finally able to get a chance to use a Windows PC as a Roon Core with the Pre Box to test it out. The behavior was exactly the same, there was no USB-C dongle or adapter. I used the AudioQuest Cinnamon as well as a standard USB A to B (one that came with an Audioengine product.) As soon as I switched the sample rate from any sample rate that was 384 kHz or lower to or from 705 and 768, the distortion was back immediately. So, I suppose that rules out the cables, USB-C adapter, and my Roon Core. So what would be the next step?

Hi @Grant_Munday,

Thanks for trying a different PC as the Core. Since this behavior occurs across multiple Cores, I’m inclined to say that it might be the DAC itself exhibiting this behavior. You should reach out to Pro-ject to see if they can investigate further.


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I have the same issue with the Project dac did you find a solution?

It seems to do it randomly sometimes it works for a few minutes then back to unlistenable distortion. Changed the cables a few times no difference. Doesn’t work on other players either so it is not Roon. Messaged Pro-Ject.

A post was split to a new topic: Issue with Pro-Ject Pre Box S2 Digital

So, the short and quick answer as to what solved my problem is the third unit; it works perfectly. To elaborate, my original issue was the distortion on 705 and 768. I had tried everything from switching cables to switching Cores. I got the second unit and had the exact same result. My first two units were purchased from a seller Amazon. Dumbfounded as to what could possibly be going on, my last ditch effort was to try to get a unit from a different, trusted source. I chose Crutchfield as they have an excellent reputation and I enjoy doing business with them. The only reason I didn’t order the product with them from the get-go was because I wanted a silver unit. The unit I received from Crutchfield is still working perfectly. There was no headache with setup, didn’t have to mess with settings and cables, everything worked just like I had imagined it should. So, I know it isn’t a technical solution, but I speculate that the issue has to do with certain units. No software was updated in between the previous units and the new one. I use an AudioQuest USB C to B straight from the computer to the DAC; everything works wonderfully. Don’t fret that it could necessarily be something on your end to be certain. Troubleshoot and if you aren’t finding what’s going on, I think there are some units out there that have issues; consider my experience. I hope this helps.



Thank you for coming back and detailing your resolution to the issue.

Yes Thank you

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