NUC (ROCK) with Perreaux Audiant DP32 USB DAC/Preamp

Hello, this is to share and exchange experiences with the common pool of knowledge…

In my set up I’m using NUC based PC with ROCK as source and my music server. This little wonder is feeding directly via USB an integrated DAC/Preamplifier from Perreaux Auidio, the model that is mentioned in the subject - “DP32”.

DP32 is based on ESS Sabre 9018S, quite powerful chip model at the time. Perreaux engineers, however, in their architectural choices decided to limit DP32 to PCM only with maximum of 24/192 over USB.

ROCK easily recognizes DP32 as “Perreaux USB Audio 2.0”. And frankly, there was no a single hick up this marriage.

As long as PCM is concerned I keep DSP upsampling “on” all the time. In case of my system, if you take CD quality PCM 16/44, for example, upsampling brings audible and pleasant difference. This I can describe as sound stage being “warmer” and filled with more volume or air.

As for DSD, because of 24/192 PCM limitation, I need to convert. I give this job to ROCK for standard DSD/PCM playback conversion. But here, I guess with no surprise to anyone, real time converted sound is different comparing to the same sources played on NativeDSD devices. Can be described as sound being less punchy, may be muddy, and bass is disappearing. The higher the DSD is (64, 128, 256) the more noticeable this loss is. Sort of logical to me… so no complaints.

Overall ROCK + Perreaux Audiant DP32 experience is truly amazing!

At last one peculiarity I have found. And here I would be very interested to know your thoughts and/or comments. When I look at the Roon Signal Path, Roon converts bit depth to 32 bit before sending this to RAAT and then to DP32. While DP32 can only receive 24bit digital stream. Playing with 32bit vs 24bit in settings… I actually believe 32bit sounds better! So, since it works, and I like it I leave it be… but it still looks a bit weird to my understanding or is it misunderstanding ?

Here’s an image with my sound path:

I’d recommend to try and upsample to the power of 2, which would then upsample 44,1/88,2 kHz to 176,4 kHz and 48/96 kHz to 192 kHz.
See, if that sounds better than upsampling both rate families to 192 kHz.

ALSA drivers seem to handle 32 bit words, then the lowest 8 bits probably just get dropped before conversion - even the best DACs struggle to reach true 24 bit resolution anyway, so no worries.

Thank you for tips!

Interesting enough “Power of 2”, despite my expectations, for CD 16/44, produced very harsh/sharp sound. Firstly not noticeable in soft electronic genre, but became very obvious in pop/rock on high vocals with painfully articulated ringing sibilants and also cymbals. For a moment, back to “default” 192 kHz.

32b vs 24b remains a bit of a mystery… May be if I come around 32bit source will try with out DSP to see how this all behave.