Naim DAC - part 2

Posted by: james n on 08 July 2009

Well i managed to slip out of work and i've seen the DAC myself now - i've been very interested given my front end is computer driven. I was quite lucky to get there early and so had the dem to myself. Unfortunately my dealer had laid on some live music. Just a girl and a guitar and she was superb and set a standard that the systems i would hear couldn't really compete with - i could have stayed and listened much longer but the DAC was calling...

Lets get the speakers out of the way first. Good looking and some very interesting design features. Sound, well the room wasn't ideal but i thought the Ovators had too much bass - almost like a badly adjusted sub. Mid and treble good though - very clean and detailed without harshness. This was driven via a 555/552/500 system.

Next up the new CDX2 with its switchable S/PDIF output. This sounded good, in fact i thought the Ovators bass was better on the end of the CDX2, mainly as the 555 goes so deep it wasn't doing the speakers any favours.

Onto the DAC - This is quite an assuming box as most have you have seen. Inputs are 4 Toslink, and 4 Coax - two of these are via BNC the other two RCA. Audio output is via DIN or RCA and there is the Burndy connector to allow PSU upgrades. USB connectors on the front and rear for an iPod or memory stick.

Internals - Jason explained that Jitter had been eliminated on the S/PDIF interface by clocking the data into memory and then clocking back out into another buffer which is synchronised to the internal clock - nothing very new there although i'll await the white paper with interest to see if Naim are doing something innovative with regards to jitter reduction.

The sound - well it was (to me) better than the CDX2 - voices had more presence more detail and the music flowed better. How good that it is i don't know - its better than the CDX2 but does that mean the DAC is a lot better or the standard CDX2 output stage isn't that hot. I'm sure that is not the case and for any CDX2 owners it'll be a decent upgrade with the option to add a PSU for further sonic pleasure.

The other thing the DAC does is that it'll play files from a memory stick and iPod. I'm a bit confused on the iPod side of things as the iPod is connected via the USB connector - Wadia connect to the Dock connector to take the raw digital data out of the iPod. As i see it (and i may be wrong), i'm not convinced that the DAC is 'doing a Wadia' - its just playing files from the iPod with the DAC providing 'transport' controls as i'm sure the USB interface wouldnt support raw data unless its in a proprietary format and the DAC is doing something else with it.

I was dissapointed to see no computer driving the DAC as with perfect jitter reduction it shouldnt really make a difference - Jason explained that the transports would sound different - but at this point i'm not too convinced. We then got onto computer ripping but again my own findings are different.

So is the DAC for me ? - well probably not. I'm not convinced by a fancy S/PDIF interface as being a good option for computer audio. The iPod connectivity is probably useful but seems a bit of an afterthought. I'd also need to hear it in my own system - the room, system and music was unfamiliar so no point of reference for me. As a digital hub in an all Naim system and an upgrade to HDX/CDX etc i'm sure it'll be a winner.

James
Posted on: 16 July 2009 by pcstockton
quote:
Originally posted by Harry H. Wombat:
demonstrated.

3. CDX2->DAC is significantly better than iPod Touch -> DAC. Don't laugh. It surprised me!



Harry,

Many thanks for the thoughts and impressions. It is really nice to hear more about it.

Regarding #3. Did you intend to say the iPod was better? If not, why were you surprised? I cant think that anyone would assume the iPod into the DAC would outperfrom a CDX2 into the DAC.

Thanks again Harry!
-Patrick
Posted on: 16 July 2009 by Harry H. Wombat
I just though that the buffering and reclocking in the DAC would decouple the DAC from the source (iPod or CDX2) and therefore I expected the results to be at least close. I was wrong! Oh and yes the CDX2 was much better but I didnt expect such a gap.

[EDIT: Just realised that may have not explained my surprise. I tend toward the "transports dont matter all that much if the DAC buffers and re-clocks" school of thought.]
Posted on: 16 July 2009 by Aleg
Hi Harry

Thank you for your interesting review.

You can find some (relatively) simple information about Blackfin
and SHARC.

I have a question which you might (or maybe not) be able to answer:

The BurrBrown PCM1707 DAC-chip is restricted to processing a maximum sampling frequency of 96khz (see datasheet PCM1704). Did they explain how they manage to process 192 kHz sampling rates? Do they downsample maybe?

-
Aleg
Posted on: 16 July 2009 by Harry H. Wombat
quote:
Originally posted by Aleg:

The BurrBrown PCM1707 DAC-chip is restricted to processing a maximum sampling frequency of 96khz (see datasheet PCM1704). Did they explain how they manage to process 192 kHz sampling rates? Do they downsample maybe?

-
Aleg


I asked the question twice and got the same answer both times: yes it does handle 192. I asked if it downsamples and I believe the answer was no. I didn't want to pursue it as I was rather monopolising the question and answer session!

Some other stuff I just remembered - there are "plans" for a DAC around 1K mark (I think) and for a higher DAC but these are not on the immediate horizon. As has been stated many times, I am sure, it should be available September for 1,950 of our devaluing UK sterling.

[EDIT: Time ran out as stampedes of NAIM devotees were all but banging on the door to get in. Doug (If it was he) took a few minutes to chat outside but to be honest I could have spent hours and hours talking about this thing and he needed to get back for the next round. I do regret not asking that question re "192 how" as I know it was a topic brought up here.

Oh - I also asked why no USB for computers and the reply was that NAIM don't like USB. I asked about Firewire and I believe the answer was that it was, to paraphrase, not commonly available but I may not have remembered that bit correctly]
Posted on: 16 July 2009 by pcstockton
Aleq,

I believe this was addressed somewhere else in the Forum, not sure of which thread though.

I think it was described as a limitation of the application of the chip, not the chip in and of itself. Or maybe I am talking out of my ass.... again.

-p
Posted on: 16 July 2009 by Eloise
If I understand what I was told correctly, the 24/96 "limit" of the 1704 DAC chip assumes that you are doing x oversampling external to the DAC. In actual fact the 1704 is capable of accepting 24bit at 768Khz. The fact it is described as 24/96 is more due to it's legacy nature and at the time Burr Brown didn't think anyone would want more than 24/96. Of course I may have completely misunderstood.

Eloise
Posted on: 16 July 2009 by pcstockton
quote:
Originally posted by Harry H. Wombat:
I just though that the buffering and reclocking in the DAC would decouple the DAC from the source (iPod or CDX2) and therefore I expected the results to be at least close. I was wrong! Oh and yes the CDX2 was much better but I didnt expect such a gap.

[EDIT: Just realised that may have not explained my surprise. I tend toward the "transports dont matter all that much if the DAC buffers and re-clocks" school of thought.]


Sweet! Thanks for clarifying. I used to believe that the transport would have little effect as well. But I have since revised that assumption based upon the experiences of others here. It probably doesn't matter to me to a great degree, but it certainly has an obvious effect on those more seasoned than myself.

thanks again!
-p
Posted on: 16 July 2009 by pcstockton
quote:
Originally posted by Harry H. Wombat:
I also asked why no USB for computers and the reply was that NAIM don't like USB.


OK. this has been said a couple of times by Dave Dever and it seems, people at Naim HQ.

If they dont like USB for computer connectivity, why is it acceptable for iPod "tethering" on the new DAC. Why is it then appropriate for use on the HDX and the very new Uniti?

How is it only "bad" when used with a computer.

I dont get it.

Anyone???

-p
Posted on: 16 July 2009 by Aleg
quote:
Originally posted by Eloise:
If I understand what I was told correctly, the 24/96 "limit" of the 1704 DAC chip assumes that you are doing x oversampling external to the DAC. In actual fact the 1704 is capable of accepting 24bit at 768Khz. The fact it is described as 24/96 is more due to it's legacy nature and at the time Burr Brown didn't think anyone would want more than 24/96. Of course I may have completely misunderstood.

Eloise


Eloise
Thank you for your explanation.

So it has something to do with the 8x oversampling capability at 96kHz sampling frequency.

I just read a bit about sample rate conversion but that gets a bit too complicated.

I will just assume then they have the ability of 4x oversampling with a 192kHz signal. Giving a factor 2 from one to the other Winker

Thanks again

-
Aleg
Posted on: 16 July 2009 by Eloise
quote:
Originally posted by pcstockton:
OK. this has been said a couple of times by Dave Dever and it seems, people at Naim HQ.

If they dont like USB for computer connectivity, why is it acceptable for iPod "tethering" on the new DAC. Why is it then appropriate for use on the HDX and the very new Uniti?

How is it only "bad" when used with a computer.

USB is used different ways for different applications...

With an iPod to the DAC, it's the only way (as far as I know) to get digital audio out of an iPod. This is the same as happens in a Wadia iTransport - there is a USB adaptor inside the iTransport and the data from this is buffered then converted to a SPDIF stream. I can't actually see how the DAC will be able to read data off a memory stick but thats a different matter.

On the HDX, all that is happening is data is being transferred (same as if you connect a memory stick to a computer).

When you are using USB to connect a computer to a DAC however, generally you are relying on the clock in the computer to control the flow of the signal (note I don't refer to it as data as it's now become time critical) to the DAC - this is adaptive mode for audio connection and is VERY prone to jitter. There have been several articles written criticizing the USB input of various DACs compared with SPDIF. There is a second mode called asynchronous but this is not widely used - only Ayre, Wavelength and dCS use this mode afaik. This improves transfer but is much more difficult to implement.

Eloise
Posted on: 16 July 2009 by james n
Good write up Mr Wombat - the CDX2 sounded very poor without the DAC - the only bonus was the thin sounding unit didnt set off the Ovators Bass. It'll be interesting to see a lid off shot and learn a bit more about what Naim have done which has passes all the other digital designers by...

James
Posted on: 16 July 2009 by Harry H. Wombat
quote:
Originally posted by james n:
Good write up Mr Wombat - the CDX2 sounded very poor without the DAC - the only bonus was the thin sounding unit didnt set off the Ovators Bass.

James


I didn't really want to comment on the Ovators as that was not the purpose of my visit but your observation wrt CDX2 and bass and Ovators was noticed and remarked upon by the listening audience as well. In defence, the room was not conducive.
Posted on: 16 July 2009 by james n
quote:
has passes all the other digital designers by...


Passed ! - damn Tamiflu Roll Eyes

Shame a computer wasnt running but lets hope those white papers are close to completion Cool
Posted on: 16 July 2009 by SC
quote:
Originally posted by Harry H. Wombat:
Ovators... In defence, the room was not conducive.

If I hear this excuse re the Ovators during SummerSounds again I think I might spontaneously combust ! Roll Eyes Big Grin

At this point the speakers have been in 16 different rooms on the tour and yet reading various posts in relation to the speaker and the forming impressions thus far, I've read this comment more than a few times and in different incarnations, as if to say in some 'mythical' perfect room they will be fine.....If this is the first of Naim's more 'universal' and wider appealing speaker range, I'm a little concerned... Frown Confused

Anyway, this is non-Dac talk...

Steve.
Posted on: 16 July 2009 by glevethan
quote:
Originally posted by pcstockton:
quote:
Originally posted by Harry H. Wombat:
I also asked why no USB for computers and the reply was that NAIM don't like USB.


OK. this has been said a couple of times by Dave Dever and it seems, people at Naim HQ.

If they dont like USB for computer connectivity, why is it acceptable for iPod "tethering" on the new DAC. Why is it then appropriate for use on the HDX and the very new Uniti?

How is it only "bad" when used with a computer.

I dont get it.

Anyone???

-p


PC

Since you are Stateside you should pick up the new issue of The Absolute Sound. There are many articles on computer based audio including a disparaging one on USB. Interesting reading.

Regards
Gregg
Posted on: 16 July 2009 by glevethan
quote:
Originally posted by SC:
quote:
Originally posted by Harry H. Wombat:
Ovators... In defence, the room was not conducive.

If I hear this excuse re the Ovators during SummerSounds again I think I might spontaneously combust ! Roll Eyes Big Grin

At this point the speakers have been in 16 different rooms on the tour and yet reading various posts in relation to the speaker and the forming impressions thus far, I've read this comment more than a few times and in different incarnations, as if to say in some 'mythical' perfect room they will be fine.....If this is the first of Naim's more 'universal' and wider appealing speaker range, I'm a little concerned... Frown Confused

Anyway, this is non-Dac talk...

Steve.


Yes - wrong forum - however I agree with your comments above.

Gregg
Posted on: 16 July 2009 by SC
I know Gregg, it was just that Harry had mentioned them along with his impressions of the DAC.....Perhaps Adam Richard will move it over to one of the Ovary threads...

Steve
Posted on: 17 July 2009 by glevethan
Steve

Hope no misunderstanding as I did not intend it to be a scolding. More like I wanted to add my agreement with your well worded comment on the "ovaries" (I do like that name Winker)

Cheers
Gregg
Posted on: 17 July 2009 by SC
Gregg - No no, not at all...I was just being clear that I was aware the comments were in the wrong place, ideally..... Smile

As for Ovaries, it's a piss-take name for me, I just cannot bring myself to spell the proper version... Eek ...When I'm being serious it's S-600...or 400, 1000, etc...

Best,Steve
Posted on: 17 July 2009 by Doug Graham
Just for clarity. The PCM 1704 DAC chip can indeed handle 192kHz sample rates. If you look at the data sheet you will see that it (1704) can be run at sample rates up to 768kHz. It can be 'limited' by what's put in front of it to 96kHz.

It supports all sample rates up to 768kHz via over sampling like this:32x24, 48x16, 96x8 and 192x4

44.1 ends up at 705.6.

There will be a white paper available at launch of the product for those of you who are interested.

Doug
Posted on: 17 July 2009 by js
looks like 32 bit is also not out of the question.

"Maximum Bit Clock (BCLK) Rate
The maximum BCLK rate is specified as 25MHz. This is
derived from the 8X oversampling of the PCM1704. Given
a 96kHz sampling rate, an 8X oversampling input and a
32-bit frame length, we get:
96kHz • 8 • 32 = 24.576MHz"
I really didn't understand that the D2A conversion was done directly from the oversampled stream and not massaged first.
Posted on: 17 July 2009 by Aleg
quote:
Originally posted by Doug Graham:
...
There will be a white paper available at launch of the product for those of you who are interested.

Doug


Doug

Thanks for the clarification, it is nice to get an explanation how to interpret the data.

Can I already apply for receiving this white paper Big Grin ?
Or will it be made publicly available?

-
Aleg
Posted on: 18 July 2009 by Lefty
I'm hugely interested in this product and will make sure I get myself down to a dealer for a listen once it's out.

Here's hoping it sounds nothing like a Benchmark or Lavry, both of which ultimately didn't do it for me. I'm also hoping it is more like the CDS3 than the CDX2 in presentation. (i.e. more analogue and fluid than forward and fatiguing)

Bravo to Naim for their recent efforts and all the new products. They have certainly been busy!

Lefty
Posted on: 18 July 2009 by John R.
Now that the Naim label and several other labels offer high resolution (24bit) downloads how do I play them with a Naim DAC? Can I put them as WAV files on a USB memory stick plugged to the Naim DAC and navigate with an iPod touch? And most important: How is the sound quality via USB memory stick or via iPod toch or other devices such as apple TV?
Posted on: 18 July 2009 by ryan_d
Well just got back from the SUmmer sounds roadshow in Chester. A well hosted event. Towards the end of the day Mark and Steve kindly let me hook up my macbook to the dac via optical, and play a few tunes, some of which were hi res (Phantom Limb from Naim and NIN both of which were at 24/96). The sound from the dac was very good, especially from the Hi res files.

We also directly compared the cdx2/dac v's the mac/dac having ripped a tune onto my mac from one of Mark's cd's for comparison purposes only. We set both off playing and ficked between them as they played. There was very little between the sound. The cdx2 a little snappier and leaner in sound, the mac sounding fuller and a little more 3d in sound. But have to say you had to listen hard to hear it with normal resolution files. WIth hi res it was no contest- the mac won.

From ipod using aiff files the sound was also very good. Very hard to tell that an ipod was being used as a source.

So in conclusion, the dac is worthy of consideration for computer use imho, if you feel that you want to use spdif as your chosen connection.

Ryan