Which DACs bypass digital filtering?

[Butterfly]

On 2/14/2020 at 2:40 PM, barrows said:

There is no DAC in the world which has 24 linearity at its outputs, period.  Find the measurements which say different and I will eat my socks!

Like I said, that does not mean this DAC does not sound wonderful, but it does mean that the company is misrepresenting its actual performance on their website, which makes me wonder about them.

Not wishing to get into a tech debate (not qualified) I could not resist the opportunity to (possibly) see someone eat their socks. That is if Martin Colloms (Ex HiFiNews Tech Ed for a while and contributor for 30 odd years – now HiFiCritic) qualifies as independent test source.

 

To declare commercial interest I have been dealing with (let’s say) Cees’ products for 7 years, so have a little background to all. Not much independent testing to confirm/question any claims. But Pavane is one reviewed by Chris Bryant 2015.

 

Buried in Critic’s Forums prior to review MC checked out Pavane on his test bench re what were called ‘outrageous claims’ re linearity/24 bit res & noise floor etc. He confirmed they were true. Ditto in Chris Bryant’s review :

 

https://www.chameleonracks.com/images/pavane/Metrum-Pavane-Hificritic.pdf

 

Further reading of 6 Moons Adagio covers next level Dac improvement but on specs only slight improvement re noise etc. – as I understand it getting to limitations of test equipment. There it covers limitations of resistors (about 14 bits) and their thermal (Johnson noise) self noise – making “32-bit resolution commercial hooey”.

Commentators do claim to hear improvements usually described as blacker background.

 

If Stereophile/HiFi News ever get their hands on a unit, maybe further test results might confirm claims.

[Butterfly]

6 hours ago, barrows said:

@Butterfly,

Oh yeah, one other thing to be careful about when looking at noise floor measurements, you have to have a signal present to accurately measure the floor on most DACs, not just powered up with no signal. 

Hi – there’s no detail re testing regimes only statements from Colloms and Bryant that claims made were confirmed – “The first thing I did on receiving the Pavane was to check its linearity and found the most accurate R2R multi-bit converter that I’ve ever measured. The error barely moves off the reference line even at -120dB (a full 24-bits)”.

 

I'm no technophobe as mentioned so can only relay comments/statements made re test results.

 

Some reviews from Critic do contain Measurements or sometimes brief comments such as above. For Hex in a brief Lab report – “Beating the Octave the excellent resolution measured about 20 bits, a -100dB tone was resolved to a fine 0.7dB accuracy confirming the transparent and deep images heard”.

 

So much comes down to how much credence you give them (and their testing regimes). So I merely wanted to point out that some independent confirmation does exist for claims made. No matter who does what though, results can always be questioned. So in some respects a pointless exercise.

 

If the claim that 4 bits contain a lot of noise and therefore ditched, using 12 bits left (of most/least significant bits summed) is a logical way to arrive at 24 bit total. If it’s believed the 4 bits ditched contain valuable info/not mostly noise etc., then it won’t stack up.

 

In the end though hearing is believing and there’s no doubt that reduced noise floors reveal micro detailing, layering and separation etc. They are not the only products to achieve this by different means.

 

Available from Critic a top tier dCS (2009) system was put through its paces with a fairly comprehensive Lab Report showing … ”With substantial data averaging, the noise floor settles at a deep -140dB, despite the presence of that full level fundamental”. Again only if credence can be attributed to Critic’s Lab regime.

 

Over the last 20 years though, can anybody dispute the fact that Dac resolution has improved - is still improving - even if Lab results are questioned/incomplete/missing ?

[Butterfly]

2 hours ago, semente said:

 

His lab testing may be fine but his listening assessment is fatally biased by taste.

 

What makes you say that in particular and aren’t all subjective reviews biased by personal taste in some way ? Showing age I’ve been reading his reviews for just over 40 years and owned quite a few products confirming his assessments. Still own a pair of MF-MC2 Speakers as it happens.

 

At £96K I would expect something to be superb. His opinions coincide with pretty much everyone else’s re top components. The only bit of gear I can think of where he’s at odds with most is Devialet.

 

His Rating System is controversial though and you are not alone in questioning his opinions but he does drag in others during listening sessions to appraise. As many may know he’s also a long time colleague of JA from Stereophile and published many an article going back for them. So JA obviously has some respect.

 

Now could just be a patriotic trait (not alone in this) but there does seem to a heavy Naim bias from his team. With takeovers/connections etc. interesting to note that Brand has suddenly sprung up large at Audiostream recently.

 

Back to measurements : “As with the Metrum Octave results, it seems that much lab data for -70dB and below has little relevance to sound quality”.

2 hours ago, semente said:

 

 

[Butterfly]

Err lively discussion … Out of interest (as a newbie) Semente, are there any Audio-zines (let’s face it how most of us find out things) that you ascribe to ? All reviews are opinions – nothing more - even if several people involved.

 

As alternative here’s an oldie if JA is/can be accepted/taken seriously/believed :

 

https://www.stereophile.com/asweseeit/705awsi/

 

Colloms has listened to many original in-Studio Master Tape/recordings etc. As close as you can get to a recording (as a ref) – Pink Floyd’s Dark Side of the Moon for one if not mistaken.

 

To quash the Audio Note as rubbish a bit harsh surely ? Unless you’ve heard one of course. Personally I’ve only ever listened to Systems up to US$300K – were they worth it imo – no. Could I happily live with one – yes.

 

So expectations at £96K are zero - I’d have to sell the house to fund a commensurate system.

 

As for Cow Dung (to lighten the load) … ‘highly rated product’ in its field.

[Butterfly]

On 2/23/2020 at 8:59 PM, semente said:

 

Some magazine publish measurements. I use these to shortlist which equipment is worth listening to.

 

 Call it an educated guess.

Thanks – follow your train of thought even if a little unorthodox. If still using a Teac mentioned (and happy with performance), you are in agreement with Reviewer opinions - which were very favourable.

 

Mentioned in previous comments above increased res should not increase distortion unless device implemented poorly, or something amiss in the rest of the chain - if you hear this of course. It’s also across the board in terms of usual Audio ingredients - to my ears at least. What it can do at the lower end say, is to reveal an amorphous bass sound to be a bass pluck and drum beat occurring at the same time. 

[Butterfly]

Mentioned previously but not included Sonnet Digital Morpheous NOS Dac. Question mark on this one but follows similar design techniques as Morpheous - Wagner/Etalon DreamDac.

 

Seems to fit the bill : Mojo Audio Mystique V3 NOS R2R DAC