M-Scaler is up-sampling to PCM705/768 kHz using Rob’s own DSP.
If someone doesn’t have an M-Scaler, they can use Roon or HQPlayer or whatever to up-sample to PCM768 kHz (for example only) if they want… but it’s FPGA will still then take up to ~90 MHz (high rate) and then to 104 MHz for noise-shaping.
Chords definitely upsample. That’s how the whole filtering works. MQA changes the original file and is not recommend. The unfolded file is not the same as the hi-res file.
OK, my ignorance occurs because the DAC is not advertised as upsampling. It’s only in the tech paper, ASFAICS.
My next question then is what is the purpose of M-Scaler?
Rob’s argued that HQPlayer upsampling is not the same as what the m-scaler does. But you are free to give it a try. Yes you still get the benefits of Chords last output stage but lose their custom upsampler.
Yes of course he will argue this. He sells an M-Scaler.
Taking most of the intensive processing (1st stage up-sampling up to PCM768kHz) out of the DAC housing and doing it before the DAC.
And doing much more intensive processing before the DAC, than he can do inside the DAC, because it would cause the FPGA to generate a lot of noise (RF), too close to the analogue electronics.
So I don’t really understand it but the Chord uses taps in their filtering. The Hugo 2 has double the taps of original Hugo. The Hugo 2 TT has double taps of the Hugo 2. Like 96k. The m-scaler has over million taps. That is supposed to get back as close as possible to original recording. Provide more depth, timber, smoothness. I haven heard it myself.
I can just comment of the Hugo vs Hugo 2. The 2 has more depth, separation, black background, and details than the original.
Sure but you can easily test this if got a loaner. I’ve search and only seen a few comments saying HQPlayer does not sound as good as the m-scaler. Thought there’d be more comparisons posted.
OK.
I read this as saying that the raison d’etre of the M-Scaler is not so much to provide an un-heretofore level of upsampling, but rather to reduce noise.
The advertising, in it’s incompleteness (at least to the unwashed), is a little misleading.
Yes I’m not saying which is better. Just that Rob will naturally always favour his M-Scaler, whether he’s listened to other software up-sampling solutions or not.
So I wouldn’t point to Rob saying anything about any other software solutions - because he has extreme bias.
There’s a lot of good technical stuff scattered all over the place on Head-Fi Forum. A real PITA to find all the bits and bobs but if anyone is interested, it’s all there.
Same goes for the creator of HQPlayer. Claims his filters sound better than Chords and the tap talk is mostly marketing.
I haven’t bothered to test this myself but I suppose at some point I could. It would just be comparing Hugo 2 internal upsampling vs HQPlayer xtr 768k.
Yes absolutely. But I haven’t pointed to anything HQP’s Dev has said 
There is no way to completely bypass Hugo2’s internal up-sampling, only the 1st stage (WTA1)…
By up-sampling to PCM768kHz in HQP, you are bypassing WTA1 in Qutest/Hugo2/TT2/Dave… just like M-Scaler does but with different algorithm obviously.
Rob still has WTA2 which takes PCM768kHz to ~90 MHz, as mentioned earlier…
I personally can’t be bothered with HQP with my Hugo2… I use HQP and enjoy it with other DACs…
I merely responded to the post by @iamoneagain in which he mentioned Rob Watts’ recommendation of using source sample rate and ideally not MQA, to which I pointed out that a small amount of my listening is MQA by virtue of being a TIDAL HiFi customer. I never said MQA was upsampling.
Yeah, re-understood.
As it turns out you were right about Qutest upsampling, too.
The point of MQA was that it’s not the original source file. It’s been altered to sound best with MQA rendering for the final stage. Chords was designed to work best with original cd quality.
About Chord and upsampling and M-Scaler…
When Chord released the M-Scaler some people (including me) were distracted by the term “upscaling”. The $5,000 M-Scaler upscales 44k to 705k and feeds that into Chord’s DACs, but Roon already does upscaling (for $0 including VAT) so why do I want the M-Scaler? And much as I admire Rob Watts’s work, and his openness in lectures and writings, I fear his explanations in this area drown us in detail and are not helpful.
I read up on it, stubbornly, and I think I understand (and I eventually bought one). And with characteristic hubris, I think I can explain what it does better than Rob can. Sometimes knowing less helps…
A few years ago, people used to say that DACs perfectly recreate the original sound because Nyquist said so. If you believe that, I have a 1982 Sony CD player I can sell you for $20,000, a bargain price for perfect sound, no? “Ok, those early devices were flawed but today DACs are perfect because Nyquist said so.” Where in Nyquist’s paper does he mention 2019? “But the paper says perfect recreation, are you saying Nyquist is wrong, do you claim to know better than Nyquist?”
Poor Nyquist never said anything of the sort. Nyquist and Shannon did math, not engineering, they never claimed that their solutions are physically realizable. “But math is the foundation for engineering!” Yes, but math does not have a problem with solutions that involve infinite numbers. Infinite is awkward in engineering, because the cost is infinite, and energy consumption, and latency. And size and weight of the equipment, and there is the black hole problem, and destroying the universe. And note that Moore’s law doesn’t help with infinite.
“But we can get close to Nyquist’s perfect.” Maybe, but like most math results, Nyquist’s theorem does not address how close to the solution you get with an incomplete implementation. That’s an engineering question,
This is what Rob Watts addressed. Looking at the infinite sinc function that is used in Nyquist’s perfection, he figured out how much computation he needed to reduce the residual error below a specific threshold. When he first did this, the requisite computation wasn’t feasible, so they made the best implementation they could, and gradually improved it, and they now claim the M-Scaler has achieved that goal. So this is not just the usual incremental improvement that the industry (including Chord) does: “this year’s model is better than last year’s model”. Specifically, he says the error (distortion) is below 16 bit, which is 96 dB or 0.0016%. This is where the million taps comes in: the previous devices have increased the tap length as they could afford to, but the million taps threshold was always there, given the target error threshold of 16 bits.
And as this approximation of Nyquist’s perfection within a specific error margin was really the objective, I believe the upsampling is incidental. The calculation delivers its results to the DAC in upscaled form, because that is the way the calculation engine can cooperate with the DAC. Why? How does this two-stage processing work? I don’t know—there is a lot of discussion on the internet if you care, but I consider that secondary. Why is the million-tap scaler a separate box and not built into the DAC? I don’t know, business reasons?
Anyway, with this understanding, we see that the M-Scaler doesn’t necessarily have anything to do with Roon’s upsampling, or upsampling in any other device (my Meridian digital speakers upsample to 705k). What is central is the algorithm, how it does the calculation to bring the error down.
(How fabulous is it? This is a technology discussion, not a product review, I’m not going to gush over how it was like removing a veil and how it opened up the sound stage and how it was just like vinyl and how the backgrounds were blacker and how the cymbals shimmered…)
I already hinted at the reason above… it’s an RF nightmare.
This is one of the benefits of M-Scaler - not just the million taps, but taking a lot of the heavy DSP outside of the DAC housing, away from analogue electronics (as I already mentioned above…).
Even with same number of taps, there is improved measured performance with a 2-box solution. Rob has confirmed 2 cascaded Dave’s (via DX connections) has some improved performance, even with same number of taps…
dCS have had 2-box solution since the 90’s. Ted Smith will be moving to a 2-box solution with his next DAC.
HQPlayer users have been using the same 2-box philosophy for years…
Rob Watts:
"The RF noise that the FPGA generates is a nightmare; it’s 12A of correlated current with large amounts of 2GHz noise. In the long term I would like to integrate an M scaler with a DAC; but I have not been able to figure out how to do it without it compromising sound quality."
I have an i3 Nuc and no DSD - so HQP is out of the picture for me. But am very pleased with what Roon does to the sound in my livingroom.
Sounds reasonable, but that wasn’t really the point.
The point was about the secondary role of upsampling.