DSD & DoP playout - M1 Mac to Gustard A26

My new Gustard A26 DAC offers native DSD512 (or DSD256/DoP) on its USB input. So I’ve connected my M1 Mac Mini Roonserver via USB to the A26’s USB input. That’s working fine for standard lossless formats & MQA, but Roon isn’t offering me a native DSD option - only DoP. And, sure enough, that’s exactly what it provides to the DAC - a DSD512 source is resampled to DSD256/DoP and shows as such on the DAC.

What then should I be doing with Roon/Mac/DAC to establish a native DSD512 playout chain?

Thanks…

MacOS core audio does not support native DSD only DoP. DoP is DSD your not loosing any quality it’s just the DSD stream encapsulated in a PCM delivery. The DSD rate you can support is limited however to the highest PCM rate the DAC supports. DSD256 requires a PCM rate of 705.6, DSD512 requires much higher. Roon only supports up to DSD256 over DoP as I don’t think it supports higher PCM than 768. If you want native DSD ditch the Mac and add in a streamer or an sbc like the raspberry pi that will support native DSD on linux or use Windows.

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Thanks - that seems to identify where the bottleneck is - the DAC supports DSD 256 over PCM, which is exactly what it’s reporting, so it’s doing its job. Just wondering then if there’s a way to bypass CoreAudio, but haven’t found an alternative yet.

Not unless your DACs manufacturer supports ASIO on Mac. Only one does to my knowledge and it’s not Gustard. Even then it’s not guaranteed to work as it’s not really supported on Mac.

Ah, all is resolved: I’d misread what passes for a manual (not Gustard’s strongest point) - the DAC supports DSD256/DoP or DSD512 Native over USB. As CoreAudio doesn’t support DSD, then DSD256/DoP is the limit. However, it supports DSD512 Native over LAN, which is ideal.

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I didn’t realise it had streaming abilities. Nice one.

It has a roon bridge and supports NAA (HQPlayer)

Did you experience dropouts And other issues with DSD over Lan? I’m really considering getting the A26 along with HQPLAYER:-)

When I first got the A26, I did experience the occasional (half second or so) dropout on the LAN. However, I’ve not had that issue for a long time now (3 months later). HQPlayer is a) very effective and b) very poorly optimised for Apple Silicon (I suspect the SDK being used). I find that, running HQP and Roonserver from an M1 Mini, it won’t push out anything higher than DSD256, whereas my AMD3900X Linux box, despite having a much lower per-core integer and floating point throughput, renders DSD512 just fine. Whilst the support for HQPlayer is good, the documentation is fairly dire.

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Newbie here. Why is HQ player needed if connecting to Lan to A26. How do you install HQ player on Mac mini and what are benefits? Thanks

HQPlayer sits upstream of the DAC (between Roon and the DAC). Whilst its functionality partially overlaps with both Roon and the DAC, it provides a very sophisticated set of filters and upsampling strategies that use the power of the host CPUs, which are far more powerful (if less dedicated) than what you’ll find in most DACs. For instance, while the A26 will support DSD512 native, it doesn’t itself upsample to that, which HQP will do. There’s a much bigger debate there about whether upsampling makes a difference, given a common source: I was doubtful, but was very (pleasantly) surprised that upsampling to DSD in HQP does make a significant and audible difference.

Be warned though, whilst the M1/M2 Macs have much greater per core throughput and memory bandwidth than pretty much any Intel/AMD system, they run out of steam upsampling above DSD256. [Update: I am informed by Jussi that any Mac with at least six performance cores will run DSD512]

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