Optimal sample rate and bit depths for Devialet Expert

[Jean-Marie]

Hi - very little/confusing information on this, so I was wondering if you could reply and also post it on your website support section to help others.

My question regards how to best feed the Devialet DAC from a computer/music server as a source.  My understanding is as follows:

PCM:
CD quality file saved at 44.1/16 - default CD/Redbook.  For this file unless you have a great way of upsampling prior to feeding the DAC (e.g. HQ Player), then better quality will result by feeding the Devialet at this 16/44.1 rate?  This is because the Devialet will upsample this input to 192/24 internally prior to feeding the amplification section and it is better to use the Devialet hardware is superior for this purpose compared to something with basic output options like iTunes.

If however is a solution such as HQPlayer is used to upsample at 192/24 prior to feeding the Devialet DAC, then this would be a better option due to it's superior processing?

Also, DSD, can you confirm that this is 'technically' the best source - since DSD64 is converted to 40bit/384 kHz pcm before it is fed for amplification.

So therefore, technically DSD will be the best source, even though the Devialet Export converts to PCM?  So, this would be one reason why something like HQ player upsampling a CD quality file to DSD64 would 'technically' be the preferred solution?

Can you also confirm that DSD128 is or isn't supported?

Upsampling does not create any new information like by magic.
The only advantage of upsampling is that it moves the aliasing frequency in the upper octaves, (for instance if you upsample from 44.1 to 96, the aliasing frequency moves from 22kHz to 48kHz). It does not magically create any information in the 22kHz to 48kHz band, but now the reconstruction filter for your DAC only needs to cut above 48kHz instead of 22kHz, which because 48k is way above the commonly accepted 20kHz or human hearing, means your filter will have less artifacts in the 20Hz to 20kHz if it cuts at 48KHz instead of 22 kHz.

This means that, unless you perform signal processing, the only thing that matter is the upsampling performed by the DAC, and anything you can do before does not change a single thing.

Same is true for increasing the bit depth: information is not being created by magic and unless you perform signal processing (and that's the reason why the Devialet is using 48 bits floating point samples if I remember correctly) increasing the bit depth does not change anything.

Jean-Marie