Difference between dCS RingDac vs. typical sigma delta DEM?

[andy2]

Does anyone know what are the differences between dCS RingDAC vs. the typical over-the-shelf DAC that also uses sigma delta with Dynamic Element matching (DEM)? From what I've read, they have the same architecture but dCS DAC seems to be specialized in some way.

 

[Ken Newton]

I don't know the specific differences, but I suspect that whatever they are they are not particularly consequential. I'd say that key design features seperating the various sigma-delta converters are; (1) the native resolution of the quantizer, (2) the order of the sigma-delta-modulator loop and (3) the output oversampling sample ratio. The main benefit of increasing any of the three is the reduction of in-band quantization noise. Each D/A unit vendor utilizes a different mix of those above key design features. For example, DSD features a 1-bit quantizer, a 9th-order modulator, and a 64x oversampling ratio. No doubt, the ring-DAC also features a unique mix.

Various quantizer-element non-linearity averaging techniques, such DEM or DWA, do reduce quantizer distortion, however, I'm uncertain as to how much one approach is superior to any other.

 

[andy2]

I always wonder why dCS trade marked their "RingDAC" if it were the same as the industry standard delta sigma DEM. I don't know if their "RingDAC" has a unique sound signature but I currently have the Arcam CD23 which has a certain naturalness especially on the human voice that I have not heard from other cd players (although my experience somewhat limited and I have not heard a lot of high end cdp). I don't know to what extend that can be attributed to the DAC, but ever since ARCAM stoped using the RingDAC, their cd players never quite had the same positive opinions from the professionals.

 

[NATDBERG]

Check out the posts in this thread: How does ring dac work ?

I think the latest dCS dacs run at 6Mhz for the switching. Main thing is the randomisation of current sources to minimise errors via the averaging.

 

[Shinja]

Typical 1st order DWA, written in a book what I had read, looks like a ring buffer. But what dCS does? No information.

 

[NATDBERG]

what dCS does is widely available to find on the internet, the basics anyway, and some pictures of the DAC boards marking out what parts do what by DIYers and the like.