Chord Electronics - Blu Mk. 2 - The Official Thread
Jul 22, 2018 at 2:09 AM Post #3,991 of 4,904
How about this particular concern regarding negatively impacting other gear? Is the bundled switching PSU theoretically as well as measurably having no negative impact whatsoever?

https://www.head-fi.org/threads/cho...official-thread.831343/page-196#post-14103671
A few hours later, Rob wanted to test the specific impact of this RF mains conditioner on both DAVE and a prototype that he brought along (that was also powered by a switching PSU). To our collective surprise, we found that our overall system's SQ improved when both DAVE and Rob's prototype were powered separate from the other components (the Zenith SE, SR7 and Pass Labs amp). As good as this RF mains conditioner is, SQ is better with either DAVE or Rob's prototype isolated from the other components. While neither Rob, Jay nor myself agreed on everything we heard during our listening sessions, we were all in agreement here and it was Rob's assessment that DAVE's PSU was likely negatively impacting my other gear.
 
Jul 22, 2018 at 2:46 AM Post #3,993 of 4,904
Rob, are you going to post your technical presentation or behind the product story for those who could not attend to London CanJam?
Am really interested to see / hear more about Hugo M-Scaler and would really appreciate your kind consideration!
 
Jul 22, 2018 at 3:33 AM Post #3,995 of 4,904
I seriously doubt the quality of the original PSU of HMS to match any of Paul Hynes or Uptone creation.

I see that you have got out of bed on the wrong side again.
 
Jul 22, 2018 at 3:48 AM Post #3,997 of 4,904
This is actually quite complicated to answer. On my Blu2 prototypes, the USB input sounded the same as an optical receiver I had added. So it seemed clear that galvanic isolation on USB was not needed as the BNC op is also galvanically isolated. But something odd happened with the Hugo M scaler - with the early prototypes of TT2 (nearly a year ago) and when I was in the USA or Japan on some days I would hear drop-outs. But these drop-outs never happened with the optical outputs on my lap-top, just the USB. And it never happened back at home in Wales. And oddly it never happened with Hugo 2 or Dave... There was something weird about the grounding outside the UK, and with TT2 and the M scaler (Blu2 was fine as well with TT2). So the last prototype had galvanic isolation added on the USB, and this eliminated the TT2 drop-out issue. Hugo M scaler actually had 3 different prototypes, and took a long time to test and ensure the best performance possible. On paper the development looks simple; just cut-out the M scaler from Blu 2 and drop it into a new chassis, but the reality was it took a lot of effort to perfect.



It's there really for other DAC's that can only handle 192k, or digital recorders so you can convert your 44.1 recordings to 176.4.



Yes the ferrites have actually been added into the driver and isolation circuitry directly. I went to crazy lengths to improve the isolation at 2 GHz - and oddly, adding ferrites on the BNC cables actually makes it sound slightly worse (oddly a bit brighter with them). But the intent is to make it easy to use without spending silly money on cables or having to add ferrites, and this I have succeeded.



Yes absolutely! Ferrites just improve the isolation, and if the isolation is good enough, adding more isolation won't help!



The DX output audio data is identical to the dual BNC output which is a mono transmission standard - all that happens is that volume control information is transmitted in the SPDIF user data, so the DX power amps will read that data and change the volume at a more appropriate point inside the DX power amp. This means that the full audio data is transmitted without any loss in SQ, but with the convenience of the H M scaler controlling the volume.

Thanks for dealing with those queries, Rob. Much appreciated.
 
Jul 22, 2018 at 4:02 AM Post #3,998 of 4,904
I seriously doubt the quality of the original PSU of HMS to match any of Paul Hynes or Uptone creation.
I believe that this is the difference between Chord and other high end companies. MSB supply an inferior single power base and lower accuracy clock as standard with their select DAC. One has to spend extra to upgrade to dual power bases and a better clock for ultimate performance. I don't think that Chord would include a compromised power supply with the M-scaler that would affect its performance.
 
Jul 22, 2018 at 4:48 AM Post #3,999 of 4,904
I wished Chord had a more consistent and less chaotic product design strategy.
It's a strategy that has brought us extraordinary quality much sooner than waiting to assemble a suite of products in each product line...

I assume many DAVE and Qutest owners are not keen on purchasing a standalone Hugo M Scaler that has a totally different physical enclosure that does not match.
Since my DAVE is on my desk (not in a dedicated floor-standing rack), HMS will go on the floor, out of sight...
 
Jul 22, 2018 at 7:14 AM Post #4,001 of 4,904
The truth is not all Linear PSUs are created equal, one could certainly find something easily for less than 40 bucks

https://www.ebay.com/itm/STUDER900-...pply-5V-6V-7V-9V-12V-15V-18V-24V/112982182860
https://www.ebay.com/itm/STUDER900-...pply-5V-6V-7V-9V-12V-15V-18V-24V/183217337016

Now let's see what other options are all about
Galvanic isolation is always a matter of degree. The SR7's regulator circuit has very high PSRR (power supply rejection ratio) and is very resistant to line noise to a level of -80dB. Is this good enough? I don't know but I have another SR7 coming in but this one will be double regulated (cascading regulators) and will have line rejection to about -150dB. Paul says that this will reject even the rectification noise (AC to DC conversion) that the PSU itself generates and should be noticeable and so I will do my own comparison.

There is so much more to PSU performance than line or ripple noise or even leakage current and yet most PSU makers seem to dwell only on the noise performance of a PSU. Other equally important factors include output impedance, operating bandwidth, transient response and settling time resulting in not just low noise but also responsiveness and explosive dynamics and very few PSU makers mention these parameters because they don't even measure it. According to Paul:

"For exceptional power supply design, it is important to consider all of these parameters and optimize them to the best of your ability. Neglect one or more of these parameters in the design stage and you will have noticeably lower performance."

The LPS-1 is certainly excellent and better than anything I have heard from HDPlex or Teradak. What I will say is that I have extensively compared the LPS-1 to the SR7 and the SR7 is noticeably superior, so much so that I have relegated my LPS-1 to lesser duty (it powers my SSD). For the things that matter the most, I use my SR7.
The double regulated Paul Hynes SR7, for example, has a line rejection of more than -150dB which is better line rejection than even the latest Shunyata Denali 6000T.
If HMS were actually consuming less than 15W, we could simply get this for $25.95 shipped with ultrahigh PSRR

http://www.analog.com/media/en/technical-documentation/data-sheets/3045fa.pdf
https://www.ebay.com/itm/LT3045-A-U...ar-regulator-0V-15V-1A-Fixed-out/253378132579

For any naysayers, I'd like to remind you a little something

https://www.head-fi.org/threads/cho...official-thread.831343/page-188#post-14084325
It's fine that you have your opinions. You certainly have the right to voice them. It's interesting, however, how you routinely denigrate and even ridicule the findings and opinions of others about things you have never heard.
If someone wants to share their experience with a cable with their Blu2, regardless of whether it is expensive or not, then let them do so in peace. I can't tell you how many PMs I have received from Blu2 owners about cables who have been afraid of posting publicly on this thread because of fear of ridicule from you.
 
Jul 22, 2018 at 7:22 AM Post #4,002 of 4,904
Yes the ferrites have actually been added into the driver and isolation circuitry directly. I went to crazy lengths to improve the isolation at 2 GHz - and oddly, adding ferrites on the BNC cables actually makes it sound slightly worse (oddly a bit brighter with them). But the intent is to make it easy to use without spending silly money on cables or having to add ferrites, and this I have succeeded.

Surface mounted ferrites? I always wondered about building a custom cable with those for Blu2 as they seem to have much better specs avail at 2Ghz. But honestly, even as is, I topped out somewhere between 8 and 12 per coax, so stopped tinkering...
 
Jul 22, 2018 at 7:37 AM Post #4,003 of 4,904
So, the way I look at this is that an ordinary speaker with its passive crossover phase anomalies spread across several octaves and bad time alignment for its drivers is doing more harm to what comes out of DAVE.

The step response of Kii 3, for example, is like you'd get with an electrostatic speaker.

ATC active is the old school approach (I used to live with the Naim version of this approach, which I liked very much). At least the crossover evils of a passive speaker are eliminated, but time alignment doesn't seem to be a priority for ATC - would like to be proven wrong. The two-driver passive SCM 19, for example:

http://www.avmentor.net/reviews/2016/atc_scm19_2.shtml
shows about 6ms of timing error between "bass" and "treble".

My reference these days is headphones where these problems don't exist (generally speaking). Speakers, in general, sound badly broken to me. So when I listen to various speakers the first question is going to be do I want to run away? I've listened to two speakers already and I wanted to run away. But I think the amp and room were especially bad...

I was focused on ATC for my future plans, but then I stumbled upon Kii 3, which seems like a really serious attempt at solving classic speaker problems. It'll probably be months before I investigate properly...
Don't forget to try large electrostatic speakers.
There are very few that can handle the very deepest bass notes, and if they do they are huge. But there are hybrids from for example ML that cover things between say 250hz to 24khz without the need for any crossover filters or phase errors from ML and others.
I have yet to hear any other speakers that can rival electrostats for transients and timbre and tonality of acoustic instruments and the human voice, not to mention their very realistic 3D soundstage both width and depth-wise.
No matter how expensive they have been, like Estelon Extreme or Beolab90s for example, all others I have auditioned have had more colorations in the midband and treble to my ears.
Cheers Christer
 
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Jul 22, 2018 at 7:55 AM Post #4,004 of 4,904
I'm in London this weekend attending CanJam and I'm dealing with a bit of jet lag at the moment and am finding it difficult to sleep. With idle time on my hands as I wait for my sleeping pill to kick in, I thought I'd post some impressions about Hugo M-Scaler (HMS). At some point soon, I'm told Chord will start an official HMS thread but I'm not sure if and when I'll post again and so consider this a "one off" although I may drop in from time to time if I feel I have something useful to contribute and if time (and my wife) allows.

Back in March, when Rob visited me at my home in California, I mentioned in my long post that he had brought along a few prototypes. I wasn't allowed to discuss them at that time but what he brought with him were prototypes of TT2 and HMS. Along with Jay, chief reviewer for Audiobacon.net, we did a lot of listening and comparing but our listening was limited to speakers only -- specifically, my pair of Martin Logan Renaissance 15A electrostats.

Because I already owned a Blu Mk2, I wasn't that shocked by the improvement HMS brought and quite frankly, I was more surprised by how well TT2 directly drove my giant pair of Martin Logans. While ultimately, my 700wpc (into 4 ohms) Pass Labs X350.8 played louder, TT2 directly driving my Renaissance sounded just as dynamic and much much more transparent. The increased speed, detail, and depth were incredible and for music playback, the TT2 by itself was capable of powering my Renaissance to satisfyingly loud levels, as loud as any of us cared to listen. Rob attributed this to the very robust current output of the ultracapacitors built into TT2's power supply. It was one of those moments where I had to hear it to believe it and it was my first real taste of what Rob's upcoming DX amps will sound like driving big speakers.

This weekend, I got my first chance to listen to a production version of TT2 driving a variety of headphones and shortly after 13:00 (London time), I got my first chance to experience TT2 with HMS driving headphones.



To give you some perspective of its size, here is a photo of Rob holding HMS that I shot for Jay's website (audiobacon.net):



Not what I would call "fit in your pocket" portable but Rob tells me he now travels with HMS in his carry on and listens to it paired with Hugo2 on airplanes "because I can" since HMS can be externally battery driven (12-15VDC). On that note, TT2 can also be battery driven (12-15VDC) resulting in the most resolving and powerful portable headphone front end in the world.

Tomorrow, hopefully, I will have the opportunity to listen to more headphones on TT2/HMS including the demanding HiFiMan Susvara and Abyss Phi CC but even with the more efficient headphones that I had on hand today including the HEK V2, Focal Utopias, Audeze LCD-X, and Meze 99 Classics, I was impressed by the incredible authority and dynamic drive of TT2/HMS but not at the expense of elegance, poise and balance. This is now muscle amp territory but with greater refinement and without the fatiguing harshness or heavy handed bluntness associated with many brute force amps. Rob's DACs have never lacked for transient speed but with TT2, you now get a tremendous uplift in transient power. This was no more evident than when listening to the sharp, piercing physicality of a trumpet being blown or a drum being aggressively struck.

How did TT2/HMS compare against BluDAVE that conveniently sat beside it? Because DAVE is starting from a higher TAP count than TT2, M-scaler brings about a seemingly more dramatic impact on TT2 than DAVE upon first listen, however, upon careful A/B, even though both DAVE and TT2 were both operating at 1M TAPS, compared against DAVE, TT2 sounded more closed in and more shallow and these differences were not subtle. It's clear DAVE's 20-element design still trumps TT2's 10-element design as far as transparency is concerned and this was just as evident when he brought his TT2 prototype to my home a few months ago, however, if I am to be honest, because of TT2's better dynamic drive, I actually preferred TT2/HSM for certain headphones with certain types of music. We'll see how I feel when I get this pairing in my home but without question, I will be buying a TT2/HMS combo for my listening room in my home office and will probably find myself listening more to headphones again. I cannot recall ever enjoying listening to a pair of HEKs more than I did today.

How did HMS compare against the M-scaler in Blu2? I hope to do more careful A/B comparisons tomorrow but to my ears, HMS sounds a bit better. According to Rob, this is "because it is better" and he attributes this to the better isolation built into HMS. Do ferrites no longer matter? During our testing of the HMS prototype a few months back, I posted that we were all surprised (Rob included) to find that ferrites actually resulted in worse sound quality and while Rob, Jay, and I didn't always agree on what we preferred, as far as ferrites sounding worse, we were all unanimously in agreement on this one. Of course, there is an explanation for this but Rob has asked that I not discuss those details at this time. Does this mean the quality of BNC cables will no longer matter? Most know I firmly believe that cables do matter and it's not just about noise and so time will tell, however, I do believe cables will definitely matter less. When I first got my Blu2, I posted that I had problems with an irritating harshness with the "el cheapo" BNC cables that came with my Blu2. I appreciated no such harshness with these same "el cheapo" BNCs today which is a very good sign.



As for why Rob galvanically isolated HMS's USB input, he did it because he was getting dropouts and galvanically isolating the USB input cured these dropouts but interestingly, he also found SQ improved even though the BNC outputs were already galvanically isolated. Hopefully, this will end talk of having to put ferrites on USB cables because that's the last thing I want to do. According to Rob, to his ears, USB and optical are now equivalent although for the purists, HMS has 2 optical (Toslink) inputs and one optical output although the optical output will limit you to 1/4 million TAPS.

What does this do for prospective Blu Mk2 buyers? If you prefer the convenience of an integrated high quality CD transport and prefer the more expensive aesthetic of the Blu Mk2's Choral chassis, then Blu Mk2 remains your best option but as I see it, for those who are more practically minded, you could get by with any inexpensive CD transport and connect to HMS via optical or BNC SPDIF.

As for price and availability, as many have already seen, MSRP is 3.5k GBP which I think is very fair considering the massive upgrade in resolution and barring an unexpected parts shortage, shipping is supposed to commence in late August (same as TT2). Exciting times for sure and I hope the world grasps what a landmark opportunity this is for all DACs.


Hello Romaz,
Really good to se you back here again!
And with some good hi res photos too!
I did some photos at Canjam Singapore but I was too lazy to upload any of them.
Cheers Christer
PS Don't miss the live BBC Proms if you have time to calibrate against the only real reference point while in London.
London is probably the best place in the entire world for live classical music and the BBC Proms are great!
PS2, oops just realized by clicking on your photos that they are not quite as hi res as I first thought.
But they are still better than some recent videos here.
 
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Jul 22, 2018 at 8:01 AM Post #4,005 of 4,904
Since we've got that Toslink output, I wonder if the SQ were any good when it's connected to those fully digital speakers directly without going through DAC at all? I'm just assuming that signal path should be (much) simpler when we're going through Toslink instead of USB

http://www.kripton.jp/fs/kripton/ks-7hqm

pvb8G0M.jpg
I think there may be a misconception about what active digital speakers contain. Because if they have digital crossover, they inevitably have their own DACs. These speakers for instance can theoretically take 192kHz input. Let’s say, they accept Toslink 192kHz, first, we have to think about whether they have good jitter rejection. Next, there is an assumption by people that just because the device accepts a frequency, the DSP for crossover will be at that frequency. This is not necessarily true. The speakers could take 192kHz toslink and run through ASRC to convert the signal to 48/96kHz to help reduce jitter and then use the DSP to perform the digital crossover. And this conversion is not as accurate as say Chord’s FPGA design. After the digital crossover, usually a DAC chip is involved before feeding a class D amplifier. It is rare to actually see the digital PCM signals concerted straight into a compatible PWM 1-bit signal for the digital amplifier. In fact, I only know of some NAD products that do this and they’re not cheap. Either way, the point is that a lot of advantages of using 250,000 taps of M-Scaler for the 4fs upsampling to Toslink would probably be lost when fed to active digital speakers.
 

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