Here's a clue...about DAC design

[cfmsp]

When asked if he would be switching to the Sabre chips, Charles Hansen said no, followed by:

 

"Besides, I think the DAC chip is only about 10% of the overall sound quality. The analog circuitry is probably 50%, the power supply is probably about 30%, the digital filter is about 10% and the DAC chip is probably around 10%. YMMV."

 

enjoy,

clay

 

 

[ar-t]

And the problem with this is?

 

[Purite Audio]

Yes10% seems to me to be a pretty decent improvement to me, especially in the weird and wacky world of hifi.

Keith.

 

[Audio_ELF]

If the Sabre DAC is (for example) 10% better than their exisiting DAC chip, then in the over all scheme of things that would only lead to a 1% increase in quality (given that the DAC chip accounts for 10% of the sound).

 

Eloise

 

[Purite Audio]

Wouldn't any improvement ( no matter how small ) be worth pursuing?

Keith.

 

[cfmsp]

"And the problem with this is?"

 

Not quite sure what I said that would suggest I thought there was a "problem with this".

 

I thought it was a clear statement about priorities in good DAC design, as I have high respect for Charles Hansen as an audio designer.

 

If you can clarify the misleading part, I'll correct it.

 

thanks

clay

 

 

[ar-t]

There really isn't a problem with that. Just the responses it will generate.

 

[ar-t]

Do I have to 'splain this to you off-line? (Inside joke)

 

[Christopher]

I went back to an interesting Q&A with Charles Hansen concerning computer audio after reading Clay’s post. If you’re interested, here is a link to Positive Feedback...

 

http://www.positive-feedback.com/Issue41/ca_hansen.htm

 

 

 

 

[barrows]

usual. I find myself in agreement with CH's priorities for DAC design. Way too many audiophiles try to simplify these things down to this or that DAC chip, when the design of the I/V stage and analog output stage have a much larger influence on the overall sound.

BTW, I do not think that Charles' response indicates he thinks that the ESS Sabre would result in a 10% improvement over the DAC chip(s) he currently uses, only that any DAC chip accounts for only about 10% of the overall sound of a DAC: In other words, the ESS could just as likely be 10% worse... The ESS is a very complicated design, incorporating an onboard SPDIF and DSD receiver, onboard asynchronus sample rate converter, and related PLL(s) and digital filters, and even onboard I/V. Typically Charles' recent designs tend to use only the straight D to A functions of a given chip, using a programmable chip to do upsampling/filtering (proprietary Ayre maths) and inputting I2S direct to the D to A section of the selected DAC chip, then using current output to an I/V stage of Ayre design as well. Seems to me it would be kind of wasteful (and I do not know if it would be possible) to use the (rather expensive) ESS chip in this fashion.

 

[ar-t]

All that is true. But a bigger concern is all the different power supplies it takes. Not sure Charlie (or myself) could find a way to make that many discrete regulators, in a practical manner.

 

[cfmsp]

 

"...But a bigger concern is all the different power supplies it takes."

 

 

ahh, yes, this is exactly the kind of cogent info I was hoping to elicit from this thread.

 

I'm a recent convert to focusing on AC quality - and a neophyte on the topic - and so was happy to see Charles give it 30% of the equation.

 

IOW, that was the 'clue' I referred to in my thread title.

 

cheers,

clay

 

 

 

 

 

[machinehead]

funny, isn't the new universal Ayre disc player based on the new Oppo BD player, which I think has a ESS Saber chip in it?

 

[cfmsp]

 

 

Jeff,

you might be right, although there's an interesting thread on AVSForum in which Charles explains in detail all that he does to/with the Oppo units. He basically throws most of it away, explaining that it's cheaper to buy fully assembled units outright than to get a 'custom' assembly of the parts he uses given the low cost of the assembled units and the low quantity he would need.

 

 

http://www.avsforum.com/avs-vb/showthread.php?p=17948105#post17948105

 

clay

 

 

[ar-t]

That is how it works. Also gets around the license issues.

 

[labjr]

The noise floor of the Sabre is lower than everything I've seen. Also, the cost of the DAC chip is relatively small compared to the cost of their products. I recall Charles Hansen talking about why he used a different TI DAC in the QB-9 than he did in his CD player. As if saving a couple dollars was going to make a huge difference in the price of the product. I realize the Sabre DAC is $30-40 dollars. But why not use it if it's even a little bit better.

 

[AB835]

I could be wrong but I believe the TI DAC's (PCM 1738) used in the C5xemp and in the QB-9 are Stereo only DACs and would not be applicable for the Universal Multichannel players.

 

[Audio_ELF]

Isn't Ayre's new universal player (the bluray one) only 2 channel analogue output anyway? It's only via HDMI that it's multi-channel. I think thats what I read in Charles' description on the thread posted above.

 

Eloise

 

[AB835]

You are correct Universal Player is analog 2 channel only. It does use the same DAC as the C5xemp, the DSD1792. Sorry I was going from my memory which is not as good as it use to be.

 

[barrows]

While the noise spec of the Sabre alone is impressive, I am not sure that this lower noise will actually be achieved in a circuit. Typically these specs are produced under ideal lab conditions, and not in a functioning, complete DAC circuit. Additionally, I rather doubt that anyone reading this forum (or anywhere for that matter) has a system capable enough to reveal the differences in noise floors of DAC chips below -120 dB.

As Pat has pointed out, implementing the proper power supplies for the Sabre is very difficult as well (also means +$$) and without perfect supplies, the chip will not come close to reaching it's noise spec.

Parts cost in manufacturing is very important, and needs to be considered. From my experience, using an ESS at $35.00 would add around $300.00 to the retail price (not considering the additional power supply cost) of a product like the QB-9, and it is certainly questionable at this point whether there would be any audible performance improvement. The QB-9 was designed to offer outstanding performance at a reasonable price-I do not think it is meant to be Ayre's final word on digital performance by any means, as such it is not a "cost no object" type of design. Perhaps if Ayre develops a computer interface/DAC of some sort for the Reference Series, more expensive "cost no object" parts will be more applicable.

 

[Elprior]

Clay, did you read that Charles is predicting the death of firewire ?

Do you really respect him !?!

 

Elp

 

[EDIT] btw, my first posts on CA were about power supply influence, but nobody seemed to care back then. I am most happy to see that, along with Jitter, others parameters may have great impacts on sonic results.

 

[cfmsp]

 

ELP,

thanks for your post, as always.

 

"Clay, did you read that Charles is predicting the death of firewire ?

Do you really respect him !?! :D"

 

Absolutely I respect him, but predictions are not facts, or even unbiased opinions, and might more accurately be described as 'hope', IME.

 

Both Charles and Gordon (and even dCS) are singing a tune (about Firewire) that is inconsistent with my views and frankly, my experience. FWIW, I bought a Firewire DAC when concern about Firewire's longevity was MUCH more legitimate than it seems to be now.

 

Apparently, even "geniuses" are not immune from the occasional self serving comment when their livelihood is involved.

 

Firewire's 'death' will eventually come - not at the hands of the lowest common denominator (aka USB), but due to a superior interface ... most likely LightPeak.

 

AFAIK, the 'real' pro audio industry has not abandoned Firewire for USB, although the 'prosumer' product manufacturers are starting to do so, but for the most part, prosumer devices are not up to audiophile standards. By 'prosumer', I mean the gear being purchased by home recordists for home studios.

 

[soapbox mode: OFF]

 

as always, your mileage may vary. I get 26-27 mpg routinely in a 540i, so my mileage is well above average. ;0

 

clay

 

 

PS, wake me when BJ Buchalter and Daniel Weiss predict the (imminent) death of Firewire.

 

PPS, all that said, I also own a USB DAC, so my 'portfolio' is diversified.

 

 

 

 

 

 

[Elprior]

Speaking of interface, I don't quite understand why there are so few ethernet implementations.

The UI development argument does not stand much, since softwares like JRiver do support UPnP (NuForce MSR1 does this I think).

 

The existing network structure is widely spread, and hugely capable of music streaming.

I'm thinking wired-ethernet as opposed to wireless (sorry mac nuts) which is rather crappy.

I'm not even mentioning the tcp capabilities and the asynchronous transmission (regarding the signal clock, since there is none in the file transfered as data), and the fact that the noisy (sound, rfi, ...) computer is kept away from the rest of the electronics...

 

This would be far more reasonable than relying on LightPeak.

Alas, the industry needs to sell brand new components and interfaces, so be it...

 

Elp

 

PS : Clay, 540i, nice choice

 

[machinehead]

A quick look at the Oppo site revealed that only their SE edition uses the Sabre DAC chip and I don't know which one of the 3 players Ayre uses.

 

Clay I might add you handle your self very nicely amongst this whirlwind of questions!

 

Jeff

 

[ar-t]

Of course power supplies are important. You can not have a low-jitter clock if it is powered by a SMPS and regulated with a '7805.