Spdif out to XLR

[Axel]

Edit: I’m running the inputs from the D via RCA to my Auralic which is driving my HD 800s in balanced mode and I’m hearing a faint 50Hz hum. Not sure if it’s the RCAs picking up mains interference or a ground loop.

First check if there is anything else connected to the Auralic and disconnect that. You could test if it's a ground loop by ground lifting the Auralic using a cheater plug (if it's safe to do so) and see if the hum goes away. If it does, then you confirmed it's a ground loop.

If so, you can try a ground lifter like this ifi GND Defender on the Auralic:
https://www.silentpower.tech/products/gnd-defender

DO NOT ground lift the Devialets though, as the manual specifically says that you should not.

Another option is to try an isolation transformer. These are some of the best.
CI-2RR | Jensen Transformers
I've used their subwoofer version in the past.

Another option if the Auralic has a balanced input with a transformer, is to make a custom RCA -> XLR cable, but do not connect the ground pin on the XLR side.

Thank you for taking the time to post this. I’ll try your solutions and let you know the results.🏻

[Jean-Marie]

If you read the white paper that Devialet published when releasing the D-Premier < http://www.dynamicaudio.jp/file/110125/2...ePaper.pdf>, you can clearly see in the diagram showing all the functions together that there is a dedicated DAC for the pre-out/subwoofer.

To my knowledge, the ‘magic wire DAC’ is an integral part of the ADH inner working and therefore cannot be dissociated.

Jean-Marie

[Axel]

I used to run my headphones direct from the speaker terminals. Would this, in theory, provide a better signal to the cans?
With the advent of roon muse and the various headphone EQs maybe I’d be better off trying to drive them in this manner again.

[Jean-Marie]

I honestly highly doubt that any difference between the two DACs can be reliably heard (real ABX test with level matching).
But since we are much more listening with our brain than our ears, you should use the way that you feel is best.

Jean-Marie

[Jean-Marie]

A precision to my answer above: It only applies to the DAC part. I have no idea about the quality of the Headphone Amplifier you are using compared to the amplifier of the Devialet, especially at the very low power needed by a headphone. So if you are reliably hearing a difference (ABX) it is likely more due to the amplifier than the DAC part.

[Axel]

A precision to my answer above: It only applies to the DAC part. I have no idea about the quality of the Headphone Amplifier you are using compared to the amplifier of the Devialet, especially at the very low power needed by a headphone. So if you are reliably hearing a difference (ABX) it is likely more due to the amplifier than the DAC part.

Thanks @Jean-Marie.
I’m being a bit picky in needing to get rid of the 50Hz hum as it doesn’t impact on the music at all. I suppose I’m really just wondering whether using another connection method will wring the last drop of sound out of my HD800s.
They are a heavy load at 300Ω and my Auralic Taurus hasn’t got enough grunt to drive them in single ended mode. In balanced mode I still have to set the volume on the amp at about 80% and control the output volume using roon but the sound is very good to my ears.
Firstly, I’m going to make a custom cable, as @hardcore suggested because I think it’s the cheapest option and easy to achieve.