ESS Sabre Reference DAC (8-channel)

[JonPike]

Yes, a hint on how things are coming would be greatly appreciated...

I am seriously torn between getting an Opus or COD now, before this run runs out, or waiting for the Buffalo...

Decisions... decisions...

PS, [shameless plug mode] will beta test, build bare boards, offer lab testing, etc... [/shameless plug mode]

[Dougie085]

I was to impatient and have been using a crappy sound card so I decided to grab an Opus for now.

[BrianDonegan]

I am seriously torn between getting an Opus or COD now, before this run runs out, or waiting for the Buffalo...

First, you shouldn't worry about them running out. Our first Buffalo boards should be here in the next couple days, and will be built and tested within 24hrs of that. You will know when we know.

[DexterMorgan]

About the jitter reduction abilities of the ESS Sabre DAC:
As I understand it the Sabre DAC reduce input jitter effectively, but just to make sure: Does that mean that I can use a non high-end SPDIF source with a mediocre clock and still get high-end performance in the end, or is the jitter reduction something intrinsic to the DAC chip after all?

Another issue, the Sabre DAC seems to be available in three levels of quality: Reference, Ultra, and Premier. What are the differences here and what quality level are you guys aiming for for the DAC board production?

Regards,
Dex

[dusfor99]

Originally posted by DexterMorgan
About the jitter reduction abilities of the ESS Sabre DAC:
As I understand it the Sabre DAC reduce input jitter effectively, but just to make sure: Does that mean that I can use a non high-end SPDIF source with a mediocre clock and still get high-end performance in the end, or is the jitter reduction something intrinsic to the DAC chip after all?

Another issue, the Sabre DAC seems to be available in three levels of quality: Reference, Ultra, and Premier. What are the differences here and what quality level are you guys aiming for for the DAC board production?

Regards,
Dex

Hi Dex,

In order to get good performance, you need 1 good clock, that being the one connected to the XIN/XOUT pad. You may put in a seriously degraded spdif signal, one thats so bad that some SPDIF to I2S chips wont even lock and still get the good performance. That being said, even when using a "not so good" clock for XIN/XOUT, I have compared the Sabre to other DAC's (not allowed to say names, but you guys know them very well) and when using these clocks, the performancve is still superior when the transport clock (I2S or SPDIF) has the most jitter. In the event the transport is excellent, and you use a mediocre clock for the XIN/XOUT, then the performance was still slightly better.

Hope this answers the first question.

Sabre Refference 64 pin TQFP 132 DNR, 115 THD+N
Sabre Ultra 48 pin QFN 128 DNR, 115 THD+N
Sabre Premier 48 pin QFN 126 DNR, 115 THD+N


Sabre Refference and Ultra both have -120dB of image rejection in the oversampling filter.

Sabre Premier has 60dB image rejection.

Numbers are when configured in stereo mode

I have had board exceed these performance levels, just not "easy to get" You have to hand select the opamps, and even caps sometimes.

Dustin

[gentlevoice]

Hi Sabre DAC people,

Anybody here who knows about a superb sounding A/D converter ... e.g. 20-24 bit at e.g. 400 kHz sampling frequency (or, if not possible at 192 kHz) w/o internal filters, oversampling or digital conversions?

Or a low-order (e.g. second or third order) delta-sigma A/D converter capable of operating at 11,289 MHz and with a "straigthforward"/standardized output? Again without internal conversions of any kind...

I'm looking for a design having the potential for outstanding sound - not necessarily the best possible data.

Suggestions are appreciated

Jesper

[Spartacus]

Hello Dustin,

what factors in a DAC do you consider of greatest importance for subjective sound quality? I find it hard to believe that there is anything to be gained by pushing DNR over 120dB .... but clearly the Sabre is doing at least one thing very right. What are your thoughts?

[dusfor99]

Originally posted by Spartacus
Hello Dustin,

what factors in a DAC do you consider of greatest importance for subjective sound quality? I find it hard to believe that there is anything to be gained by pushing DNR over 120dB .... but clearly the Sabre is doing at least one thing very right. What are your thoughts?

This is a tough question an answer, and many people carry vstly differing opinions on this subject. All I can say is what I use as the methodology when designing the DAC.

1. Most important in this design was immunity to jitter coming from the input transpart, whatever it was.

2. Then I tried to keep the responce to be "linear phase" so that the group delay was constant.

3. Use enough bits in each part of the chain such that the quantization error was not enough to cause degredation of DNR at final output.

4. Use simple Dynamic element matching algorythm, i.e dont make anything more complicated than it needs to be.

5. I know its last, buts its the one I spent most of the time on, so this one should really be first, do a damn good job of matching EVERYTHING, even parasitics in the analog section of the chip.


I hope that answers it

[gentlevoice]

... thought some of you might know about ADCs as well... (see two posts above this for my question)?

Would you know about this Dustin? Or maybe where to ask/search?

Regards,

Jesper

[dusfor99]

Originally posted by gentlevoice
... thought some of you might know about ADCs as well... (see two posts above this for my question)?

Would you know about this Dustin? Or maybe where to ask/search?

Regards,

Jesper

For ADC's im not too familiar with. Sorry Jesper.

Thanks

Dustin