[Sonic77]

It has been on for a few hours. It is warm but not hot. I will have to check but the Dave may be running cooler than it does when used on its own. I will keep an eye on the temperatures and report back.

Just listening to this at the moment with Blu2 and Dave streaming on Tidal via an Auralic Aries. Track 2 is sublime. In fact it all is.

Excellent.

 

[lovethatsound]

Coincidentally I've auditioned a pair in my preferred headphone store yesterday – while I was bringing my HE1000 for repair of a loose connection on the right ear cup (two weeks waiting time expected). So I just had my (modified and equalized) HD 800 for comparison, connected to a DAVE. In short: I was rather disappointed by the sound. I couldn't reproduce the reported impulsivity and dynamics – my HD 800 sounded way more lively and dynamic throughout the frequency spectrum. Also, I found the treble to sound rather cold and lacking texture, I'm inclined to call it smeared and sleek. For the sake of fairness I tried a bit of equalizing (lower and mid-treble down by 0.4 dB and the like), but of course that's no substitute for serious equalizing, so it's impossible to draw a final conclusion. I guess that's not what you wanted to read...

Must of been one of those rogue pairs of utopia that are supposed to be going around lol.

 

[onsionsi]

Congratulations @Triode User,

For your Two BNC Cables are they with 75 ohm and can you post the link for these cables.
Also may we know what's the thing will you spend a lot of money for Blu2?

 

[GryphonGuy]

It has been on for a few hours. It is warm but not hot. I will have to check but the Dave may be running cooler than it does when used on its own. I will keep an eye on the temperatures and report back.
...

I can report that without a Blu MkII, running the DAVE using 24bit/384kHz material, it does run much cooler than 16bit/44.1kHz material. I guess this supports the theory that the Dave works its magic on the lower resolution music data and less so on the higher resolution music data.

GG

 

[stvc]

Unfortunately it is not just your ear that is making an impression on you with an expensive cable, it is also your eyes looking at it and your brain telling you how much it cost. In other words expectation bias will be in full flow. And to that extent you cannot trust your ears.

Hear to believe

 

[Rob Watts]

I was wondering if Rob Watts believe in specific lengths of BNC cables to connect Blu2 to DAVE. Berkeley Audio Design Alpha USB manual says "1.5 meters is a good default length for USB, SPDIF and AES cables". I've heard this from other places that I admit I can't name now from before. Something about too short of a digital cable is not good but I can't remember why. Not sure if it applies to Blu2 & DAVE connection.

No the length is not important (in terms of short length) as it is impedance matched; there are no reflections to worry about, short or long. But the cable does has a frequency response; so longer lengths will attenuate high frequencies, and this could make the SPDIF rx not lock onto the data. We have tested 768 kHz at 5 M, and it works perfectly. However, the cable length must be the same, as Dave's dual data detector relies on sync of data between the cables.

I use 0.5M on my office, and 3 M on my main system. I have just received the high-end BNC, so when I get back from Asia I will listen to all 3 sets of cables and will post back.

When I installed galvanic isolation on the dual BNC, it did indeed sound a lot better; also RF filtering on the PSU of the output buffers made a difference too; I ended up improving the RF filters. So the RF noise that Dave receives is an issue, hence my recommendation that RF quality cables be used - from both the data recovery and sound quality POV. Again, when you do listening tests, the warmer sounding cable will be the best one, as only RF noise can change the sound quality with Dave.

Rob

 

[stvc]

No the length is not important (in terms of short length) as it is impedance matched; there are no reflections to worry about, short or long. But the cable does has a frequency response; so longer lengths will attenuate high frequencies, and this could make the SPDIF rx not lock onto the data. We have tested 768 kHz at 5 M, and it works perfectly. However, the cable length must be the same, as Dave's dual data detector relies on sync of data between the cables.

I use 0.5M on my office, and 3 M on my main system. I have just received the high-end BNC, so when I get back from Asia I will listen to all 3 sets of cables and will post back.

When I installed galvanic isolation on the dual BNC, it did indeed sound a lot better; also RF filtering on the PSU of the output buffers made a difference too; I ended up improving the RF filters. So the RF noise that Dave receives is an issue, hence my recommendation that RF quality cables be used - from both the data recovery and sound quality POV. Again, when you do listening tests, the warmer sounding cable will be the best one, as only RF noise can change the sound quality with Dave.

Rob

Thanks Rob for the clarification. Doubts cleared.

 

[Rob Watts]

Hi, I am a new member and I'm going to start with a dumb question, but I'm not sure that I fully understand what M Scaler is doing - is it not just similar to software upscaling? Rob Watts had previously advised against using software upscaling into Dave, so how is M Scaler different? Are there any conclusive findings yet on whether, and by how much, the Dave is improved by using the Blu II M Scaler?

I run a Dave into a Chord SPM1200 MkII into Dali Euphonia MS4 speakers and am very happy with my system. It is hard to imagine a significant improvement to this. Is M Scaler just go faster stripes type marketing, or are the improvements genuine and significant? I guess I just don't understand how you can improve over and above the original data being presented as cleanly and accurately as possible, which is what I have always sought to achieve.

Sure the M scaler is for better marketing - but I use the term because it makes a vast difference to the sound quality, and these changes were unexpected. In the past, every time you double the tap length, you double the accuracy of the interpolation; so timing errors are halved; and I expected the 512,000 taps that I initially designed to simply sound better than before; indeed, I actually expected the law of diminishing returns would apply, and that it would be no great deal.

But I was profoundly wrong; when I listened to 512,000 WTA taps it was a very different sound to the 164,000 taps in Dave. So I decided to push the boat out, and get that absolute max out of the 200T FPGA, which actually was a big design struggle - but I managed to exceed 1 M taps with 1,015,808 taps.

Now 1 M taps is very personal to me, as going back to my university days in the early 1980's I said that 16 bit digital would never work properly unless we had ideal sinc function interpolation filters with the coefficients of the sinc function accurate to better than 16 bits; and that if we didn't do this, the timing errors in reconstructing transients would be too audible. So the 1 M taps had a lot of personal interest for me. So when I actually heard the huge changes wrought by a million taps, plus the technical fact that we are now guaranteeing reconstruction to full 16 bit accuracy, meant that it would make sense to promote the idea by giving it a unique name.

What is strange is that there really is something odd about 1 M taps; you can convert Blu 2 to 500 k taps by selecting 384 kHz output - and the difference is huge. You can also go to video mode, when it is 2/3 M taps, and that too is a big step backwards. So the M scaler is not just marketing hype!

Going back to your original question - yes an M scaler is the same as software up-sampling - but differs in two important ways - one being the use of my WTA algorithm; the second is the huge amount of computational power needed to do true 1 million taps 16 FS filtering; to do this I use 528 DSP cores running in parallel - when a PC has only 8 cores and is not suited to do real time processing.

Rob

 

[Rob Watts]

My Blu2 arrived about an hour ago.

You get in the box:-

The Blu2
A printed manual
A power chord
A remote (not a small dinky one like with the Dave)

No USB cable that I could see despite what it says in the published info on Chord's site.

I had already bought a pair of identical BNC 1m terminated cables (£20 variety) so I was good to go. There was a brief moment when I wondered if I should have quick listen just with the Dave to be able to compare the sound with the Blu2 added, but stuff that, the Blu2 was here and I wanted to listen to it.

After switching off the Dave, then connecting the cables and then switching the Dave and Blu2 on it was time to select the dual BNC connection. I had them on BNC 1 and 2 so I selected BNC 1, waited the 3 seconds and up popped the confirming display.

By now the Blu2 had had a 12 second burn in so time to play . . . . .

Shelby Lynne, "Just a little lovin' ", first track.

Good grief, there was no need to have listened to the Dave by itself to refresh my memory. There was a big difference in sound with the Blu2 added. The best way I can describe it is to say that it is like the Dave but more so. Everything I like about the Dave is multiplied by a factor of 5 or 10. Not different, just more of the same if that makes sense.

Next was Laura Marling, "Once I was an eagle", track 4. Same thing again with the sound. It is simply stunning. Simply simply stunning.

I have come through to my computer to post this now but I will be going straight back to listen.

Welcome to the club!

You can see now why I run around the world with a Dave and a Blu 2 in my carry on. Once you get used to the sound, I find I can't live without it.

What I hope now is that the rest of the audio business wakes up and stops denying that long tap length filters are unimportant or bad - this nonsense that short tap length, no ringing filters is the best sound possible is completely destroyed once one actually listens to an M scaler.

Rob

 

[Malcyg]

Thank you for the reply Rob, I am privileged to get my first response from the man himself and was not expecting that! I'm still not sure that I fully understand, but given that I have a Blu II on order, I should find out for myself soon enough. I didn't really understand some of the stuff that you wrote about the Dave, but I certainly have been very happy with it. People who visit always comment on how clear and lifelike my system sounds so, if real improvements on that are possible, then I'm looking forward to hearing it.

I also look forward to your comments about the BNC cables. I believe that my Dave benefitted from better cables and am wondering what to do about the necessary twin BNC cables that I will need to obtain.

 

[Triode User]

Congratulations @Triode User,

For your Two BNC Cables are they with 75 ohm and can you post the link for these cables.
Also may we know what's the thing will you spend a lot of money for Blu2?

Yes my two BNC cables are 75 ohm. This is the link for them. Because I bought a pair the seller provided 1m for the same price.

http://www.ebay.co.uk/itm/CANARE-BN...hash=item4b15ac92da:m:mOHbN6e4fevAhN1VLIBqfww

I do not intend spending any money on anything for the Blu2. It seems to work just fine with cheap input USB cable, cheap power chord and cheap BNC connections to the Dave.

 

[adyc]

can also try blue jeans BNC Belden cable.

 

[adyc]

My dealer still has no idea when Blu2 will arrive. Agony wait.

 

[JaZZ]

Sure the M scaler is for better marketing - but I use the term because it makes a vast difference to the sound quality, and these changes were unexpected. In the past, every time you double the tap length, you double the accuracy of the interpolation; so timing errors are halved; and I expected the 512,000 taps that I initially designed to simply sound better than before; indeed, I actually expected the law of diminishing returns would apply, and that it would be no great deal.

But I was profoundly wrong; when I listened to 512,000 WTA taps it was a very different sound to the 164,000 taps in Dave. So I decided to push the boat out, and get that absolute max out of the 200T FPGA, which actually was a big design struggle - but I managed to exceed 1 M taps with 1,015,808 taps.

Now 1 M taps is very personal to me, as going back to my university days in the early 1980's I said that 16 bit digital would never work properly unless we had ideal sinc function interpolation filters with the coefficients of the sinc function accurate to better than 16 bits; and that if we didn't do this, the timing errors in reconstructing transients would be too audible. So the 1 M taps had a lot of personal interest for me. So when I actually heard the huge changes wrought by a million taps, plus the technical fact that we are now guaranteeing reconstruction to full 16 bit accuracy, meant that it would make sense to promote the idea by giving it a unique name.

What is strange is that there really is something odd about 1 M taps; you can convert Blu 2 to 500 k taps by selecting 384 kHz output - and the difference is huge. You can also go to video mode, when it is 2/3 M taps, and that too is a big step backwards. So the M scaler is not just marketing hype!

Going back to your original question - yes an M scaler is the same as software up-sampling - but differs in two important ways - one being the use of my WTA algorithm; the second is the huge amount of computational power needed to do true 1 million taps 16 FS filtering; to do this I use 528 DSP cores running in parallel - when a PC has only 8 cores and is not suited to do real time processing.

Rob, I'm aware that the final verdict about how close to a perfect «reconstruction filter» the M-Scaler gets is postponed until Davina is in operation (given that existing «low-res» recordings suffer from imperfect ADC and/or decimation); but since most of my favorite music is still in 44.1 kHz (and will remain), how much, in your opinion, is now missing with the M-Scaler/DAVE playing 44.1 kHz recordings – compared to the best audio formats available, let's say good 384 (or 192) kHz recordings? Have you already been able to decimate existing hi-rez recordings to 44.1 kHz with a Davina prototype and do a comparison?

The other way round: How much do hi-res recordings benefit from the M-Scaler now compared to the redbook format?

Another question: It has been speculated that the PPA amps will work with an M-Scaler alone, without the DAVE. Is that realistic?

 

[emrelights1973]

I get the part of the Dave + blu2 makes something specially but those who are looking for a cd transport for their dacs/streamers, does blu2 bring something speciall or not?
Is it a "Dave only" product or does m scaler will work with my naim nac272 till I get a Dave as Well?