[Rob Watts]

How many taps do we need for “next level M Scaler” to get subjective improvement comparable to improvement between 500k and 1M in current model? 2M? 24M?

A lot of work has been done on this very issue, and more work is ongoing. Suffice to say that I should have some news next year.

@rob,
With ever increasing small signal accuracy giving better depth perception and our own ability to perceive relative distances in sound, similar to the way we perceive direction from minor timing differences from ear to ear ?
Is it possible that this is caused by more and more reflected vs direct sound reaching our ears at minute differences in level and timing as the distance increases, and the more accurate those signals are replayed the better we hear depth in recordings ?

I suspect that you are correct - to perceive depth properly we need the depth cues to be preserved in amplitude and relative timing (phase) as accurately as possible.

The puzzle is why we need -301dB with zero phase and amplitude errors - or why an error however small is perceptible - that's the big mystery.

 

[DJJEZ]

A lot of work has been done on this very issue, and more work is ongoing. Suffice to say that I should have some news next year.

 

[sm60]

Sorry but you are incorrect. The output from the volume control is simply not truncated - nor is it dithered - but aggressively noise shaped, so that the signals within the audio bandwidth are perfectly preserved. By perfectly, I mean it will reproduce a -301dB signal to an accuracy better than +/-0.001 dB and with a phase shift of within +/- 0.001 degrees; this level of accuracy is essential in order to maintain the perception of depth and detail resolution. To illustrate the power of this noise shaper look at the 16FS output of the M scaler's truncator to 24 bits:





You can see that the noise floor is at -390dB - and this is actually down to my test vectors. The noise shaper starts to kick in at around 16 kHz. Subjectively, this is completely transparent, in that there is no loss in SQ if a digital module can reproduce -301dB with zero amplitude or phase errors - from this perspective, then the volume control function can be considered lossless. All of my modules have to pass this demanding test, plus of course listening tests, before they can be incorporated into a design.

This approach is very radical, and to some would be considered excessive; but after many listening tests, it is the only way to accurately reproduce soundstage depth. Generally, digital volume controls are not done with such aggressive 11th order noise shaping - they are normally dithered when truncating, which is subjectively not lossless. Some don't even do that, just discard bits, which is just plain stupid/incompetent due to the severe small signal distortions introduced.

PS - just so you can see the -301.03 dB signal zoomed in:


The level is -301.030 dB, against -301.299957 dB ideal value

I’m sorry, Rob, with all due respect, but your analysis differs from John Atkinson’s measurements in Stereophile, where he showed that the Dave had resolution less than 20 bits. Perhaps you can enlighten us on where his analysis is incorrect. John has been measuring D/A converters for over 20 years, and generally his methodology has been consistent. Feed the D/A a 16-bit signal and measure its S/N ratio and then compare with the result using a 24-bit signal. Ideally, you’d expect to see a 8 dB drop in noise. This never happens. The very best converters manage 21 bits of resolution, meaning the noise drops by 5dB. The Dave is not in this select group, unfortunately.

 

[sm60]

A lot of work has been done on this very issue, and more work is ongoing. Suffice to say that I should have some news next year.



I suspect that you are correct - to perceive depth properly we need the depth cues to be preserved in amplitude and relative timing (phase) as accurately as possible.

The puzzle is why we need -301dB with zero phase and amplitude errors - or why an error however small is perceptible - that's the big mystery.

I have to resist the impulse to laugh out aloud with all this talk of S/N ratio being -300dB. As I said in high end audio, people make up all kinds of crazy numbers. At this point, I’d be much happier with a Dave and Blu Mk2 that doesn’t audibly distort every time I change inputs or power cycle either component. The sad thing about these products is the lack of any way to update the software except by shipping the units back to the UK to correct their obvious defects. It sounds like the double BNC connection is highly problematic and there’s some kind of synchronization error happening where the Dave is failing to lock on to the clock signal from the Blu2. I’ve experienced this type of digital noise in the late 1980s when external D/A converters were in their infancy (early Theta Digital DACs). Sad to see that 30 years later, some designers haven’t yet figured out how to make products more reliable. I’ve done a number of experiments to figure out what’s wrong with my Dave and Blu2. It looks like either synchronization errors or some fault condition occurring in the DSP itself. The Blu2 transport will work fine for one or two CDs and then, wham, out of the blue, the Dave will start distorting. This never happens with an external CD transport — I have the CEC TL0 CD transport, which when connected to the M-Scaler works just fine with no crazy digital noise. Of course, the power cycle problem occurs regardless whether I’m streaming or playing CDs. I’ve learned through experience never to play the Dave through my speakers until I run it through a couple of sample tracks and that seems to reset the DSP so the Dave is not audibly distorting. When the two work properly, they do sound fine, but in terms of reliability, it’s certainly the worst digital high end product I’ve owned, and I’ve owned a lot in the past 25 years. My experience is not unique. My dealer confirmed others have had the same issue, which is why the Blu2 has been discontinued.

 

[iDesign]

Have you considered selling your Chord products and moving to a different thread?

 

[jlbrach]

yes, it sure seems like this fellow would be better off owning another brand

 

[Torq]

Zero issues with my Blu Mk2/DAVE combination in the last 2 years (which is when I added the Blu Mk2). No drop outs, no distortion, no power on/off issues. Not that this means the same is necessarily true for anyone else. But if it was a systemic issue, rather than a unit-specific one, I'd expect to have encountered such a problem at least ONCE in that time.

If I was having such issues, each unit would have gotten one service visit each to get it sorted, and if that didn't resolve it I'd either be going after the dealer and/or the manufacturer for replacements or refunds. If not resolved at that point, I'd have gotten rid of them and replaced them with something different.

I was told the Blu Mk2 was discontinued because the drive mechanisms were no longer available, and no suitable replacement was available.

 

[MarkusBarkus]

...yes, but then you wouldn't be able to crab about it and post how bad it is. You'd have to just move on with things and enjoy your alternative selection.

 

[sm60]

Have you considered selling your Chord products and moving to a different thread?

Yes, I have considered selling my Chord products, and I'm sure eventually I will do that. I realize my ranting on this newsgroup is not something everyone wants to hear, but it's fair to say that as a consumer of these really high priced products, I should be allowed to relate my actual experiences of owning them. I own a high-priced Tesla, which has so far (touch wood!) worked absolutely reliably, even given the weekly software updates. If my Tesla gave me the kind of problems the Dave/Blu2 do, I would obviously rant on the Tesla newsgroups! I have no axe to grind against Chord. I like many things about their design, for one their size (easy to hold with one hand, not something you can say about other DAC's!), and generally when they work, they sound fine.. Unfortunately, perhaps I ended up with a lemon, although from the comments others have made on this newsgroup, I don't think I am alone in my experience. Chord needs to hear this feedback. About the Blu2, I am relaying only what my dealer told me: the Blu 2 was discontinued because of increasing reliability problems. He in fact strongly suggested that I should not get the Blu2, but get the M-scaler instead. I decided otherwise, for purely cosmetic reasons (I can't stomach the tinsel colored plastic beads on the M-scaler, which are on many of Chord's portable products as well -- they seem very tacky, but that's my personal view of course!).

Regarding getting the products serviced, it's no easy matter if you live in the US. I have had experience in this matter, as I have owned many high end digital audio products. For example, I owned a dCS Verdi SACD transport, which always kept failing to read SACDs properly. Sony made the transport, and dCS required me to ship the Verdi back to the UK at my expense. It took several months, and when I got it back, it worked for a few months, and then promptly exhibited the same problems again.

So far, my annoyance at the Chord units has not arisen to the level of wanting to get rid of them, except for occasionally ranting on this newsgroup! When the Dave distorts, or the Blu 2 transport chokes on a disc, I curse, and then adopt some workaround. So far, they continue to work for the most part, with periodic power cycling, and then making sure the DSP in the Dave gets reset by running through a couple of sample tracks at different resolutions (by the way, this trick I learned on this newsgroup, proof that others have had exactly the same problem, and figured out workarounds). A well designed product should be software upgradeable. It's crazy to think that in 2021, a company like Chord puts out a digital product that cannot be updated remotely. They seem 20 years behind the times here.

 

[griff500]

It must be at least twenty years since I've seen anyone use the word 'newsgroup'.

 

[sm60]

...yes, but then you wouldn't be able to crab about it and post how bad it is. You'd have to just move on with things and enjoy your alternative selection.

Very true! Wise words indeed. But, if you search this very long thread, you will find each and every problem I have reported, others have too. I am not unique in my experience. The Blu2 thread also has people complaining about the transport. If you have a perfectly working Dave/Blu2, consider yourself blessed! I wish I was in such exalted company!

 

[MarkusBarkus]

It's crazy to think that in 2021, a company like Chord puts out a digital product that cannot be updated remotely.

...now that I agree with. A digital/software dead-end should be a thing of the past.

 

[sm60]

It must be at least twenty years since I've seen anyone use the word 'newsgroup'.

Ah, I'm dating myself, clearly. Just to be absolutely transparent, my first computer program was on a set of punched cards, written in Fortran, on a mainframe Digital Equipment Corporation DEC-10 computer. Yes, back in the days when assembling a playlist meant going down to a record store, and buying a vinyl disc or a cassette tape! Life was simpler then...

 

[griff500]

...now that I agree with. A digital/software dead-end should be a thing of the past.

It's not a product that has just been brought out though and I'm not sure what updates it needs? I'm perfectly happy with mine.

 

[griff500]

Ah, I'm dating myself, clearly. Just to be absolutely transparent, my first computer program was on a set of punched cards, written in Fortran, on a mainframe Digital Equipment Corporation DEC-10 computer. Yes, back in the days when assembling a playlist meant going down to a record store, and buying a vinyl disc or a cassette tape! Life was simpler then...

I can't claim to have done that, but I do remember newsgroups.