Chord Qutest question ...

[camverton]

Same here. The theory is that the M-Scalar makes the TT2 sound more realistic whilst it’s essential for the Dave. The detail and smoothness of the Dave is impressive but I’ve never found it that engaging. More hifi and less music. Goes very well with Chord amps, for which I have no taste i.e. further emphasises detail and smoothness but at the cost of the energy of live music which the TT2 and Qutest do have.

Thanks, interesting. It has to be said that I do like detail as it is one of the things that connects me with the original, usually, acoustic performance. It might explain why I like electrostatic speakers and similar. However it has to be good detail and not over emphasised as one might get by turning up the sharpness setting on a TV; initially impressive but ultimately fatiguing and distracting. I guess we all perceive sound differently and what works well for one person might be a turn off for someone else.

As for adding a m scaler to a Qutest or TT2 the benefits depend on the music but I’ve found it easier to follow stuff like harpsichord music, full of transients, and once described by Thomas Beecham as the sound of cats copulating on a tin roof. At the same time, and much more nebulous and difficult to describe, I found it makes the music sound more natural and less artificial.

 

[beammeup]

Answer: Plixir Elite BDC Power supply with Statement DC Cable or Ghent JSSG360 Gotham GAC4/1 UltraPro DC Cable. Audiowise SRC-DX. Dual-BNC into the Qutest with the HF and LF filters from Thor Labs, MiniCircuits, or Audiowise.

HQP -> USB -> SRC-DX -> Dual BNC -> Qutest.

Upsample to 705k/768k to bypass the internal WTA1 filters.

That's a very exact recipe.

I take it you've spent a lot of time tweaking your Qutest to the very best it could possibly be!

What did it sound like naked to you?

 

[beammeup]

Anyone any idea where 3V as an acceptable line level came from?

I don’t understand why anyone would want this high a level. It is far higher than most power amps could handle (typically 1-2V) so no advantage when using a passive preamp even into amps at the upper end of the range. The now standard 2V for digital was viewed as too much for many preamps when it was introduced and arguably a key reason people didn’t subjectively like CD as it often subtly clipped their preamp stage leading to a perception of harshness and thinness. I don’t see why the figure seems to be creeping ever upwards. It basically means I can’t use the fixed outs on the DSX.

About the Qutest, I've read somewhere that the 2V and 1V option is digitally attenuated. So in essence the 3V option would be for the purist!

All interesting stuff.

 

[camverton]

About the Qutest, I've read somewhere that the 2V and 1V option is digitally attenuated. So in essence the 3V option would be for the purest!

All interesting stuff.

Into equipment that can take 3v I’ve never detected any difference once levels have been matched. In practice I just stick to the “standard” 2 volts and have enough trust in the make and designer not to worry that their implementation may be problematic.

 

[John Phillips]

1) If it is secret how do you know that it is entirely orthodox? TAP length? The problem is that the iterations as you go up the model range only make a small difference and ime and imho aren’t really worth bothering with until you either go from bottom to top of range or add an m scaler.
...

Keith Howard published an article in HiFiCritic on the M Scaler which does reveal the Chord approach to audio reconstruction. The article is on the Chord site.

From that source, Chord's approach, which is in line with their marketing and with the online tests I have seen, is very conventional although heroically engineered.

According to Howard, the proprietary "WTA" part is the windowing function which is normally applied to the conventional filter coefficients, to deal with the impact of a non-infinite filter length. This is apparently not one of the conventional windowing functions. It is one that RW has said that he tunes according to his ear. So I think we do have a very conventional DAC with RW's proprietary twist.

 

[Tim Jones]

2) as has been observed above, many who swap the wallwart out cannot evidence what has been impacted and many simply return to the original. Most owners have stuck with what Chord provided and remain happy. So, no, the majority do not think he‘s wrong.

Part of the solution to this conundrum may lie in Tony's point about impact on other things. I notice, for example, that the Qutest wallwart is a component of my (ongoing, but much diminished) phono hum issue.

 

[20hzFlat]

I

OK, clearly no point in discussing anything with you, and that’s fine. Hope you find plenty of people here to engage with who you’ll enjoy conversing with.

I think you need to go back a read what you put. I’m sharing my experiences but they your are basically dismissing it while offering no substance in your experience and you wonder why. You might as well say I don’t believe you. I’m more than happy to talk about things with folk.

 

[John Phillips]

It’s fascinating how we all hear things differently as I find Chord DACs natural sounding whereas most others a bit synthetic. ...

Exactly. I find Chord DACs very natural too but observation of others' negative opinions of them reveals we are all different in what we perceive. It is only a problem when someone gets didactic and insists that what he/she perceives from listening to a DAC or from listening to a fuse is the only valid perception and that other must perceive that too.

 

[camverton]

Keith Howard published an article in HiFiCritic on the M Scaler which does reveal the Chord approach to audio reconstruction. The article is on the Chord site.

From that source, Chord's approach, which is in line with their marketing and with the online tests I have seen, is very conventional although heroically engineered.

According to Howard, the proprietary "WTA" part is the windowing function which is normally applied to the conventional filter coefficients, to deal with the impact of a non-infinite filter length. This is apparently not one of the conventional windowing functions. It is one that RW has said that he tunes according to his ear. So I think we do have a very conventional DAC with RW's proprietary twist.

Thank you. If it is all down to his proprietary twist then I am grateful as it suits me well and lets me get on with enjoying music without wondering why it doesn’t sound quite right.

 

[camverton]

Exactly. I find Chord DACs very natural too but observation of others' negative opinions of them reveals we are all different in what we perceive. It is only a problem when someone gets didactic and insists that what he/she perceives from listening to a DAC or from listening to a fuse is the only valid perception and that other must perceive that too.

Quite right. My recent hearing woes, thankfully partially recovered from, have taught me just how differently we can hear exactly the same sound and that is before we consider the possibility of expectation bias and other psychological factors.

In practice most hearing changes, other than ear wax perhaps, are slow enough for our brains to adapt. An overnight change reveals just how variable our hearing is. Little wonder we can’t be in accord with every opinion expressed!

 

[camverton]

I

I think you need to go back a read what you put. I’m sharing my experiences but they your are basically dismissing it while offering no substance in your experience and you wonder why. You might as well say I don’t believe you. I’m more than happy to talk about things with folk.

There really is no point in continuing this other to note that you joined this forum on April 1st and ask if that is relevant , but seriously, best wishes but over and out.

 

[20hzFlat]

There really is no point in continuing this other to note that you joined this forum on April 1st and ask if that is relevant , but seriously, best wishes but over and out.

Im glad you agree especially when I suspect your out your depth going by our brief encounters. Ive been on here years and recently signed back up to buy something thanks Sherlock.

 

[cb01]

That's a very exact recipe.

I take it you've spent a lot of time tweaking your Qutest to the very best it could possibly be!

What did it sound like naked to you?

In stock form, it is very sensitive to the quality of your local mains. I've heard it in 3 different grids across two US States and, with the OEM SMPS, the sound quality in stock form can vary quite greatly in my experience. It could sound slightly thin and etched. But not always. Late nights (with cleaner power) in the PNW always made it sound smoother and more organic. So I am inclined to believe both sides when they say "Qutest sounded like X", because it probably did.

Upgrading to an iFi Elite or Allo Shanti power supply was the first major step in reducing this variability; I settled on the Shanti mainly because it was cheaper and sounded very nearly as good. I then upgraded to an SBooster with the little add-on ultra dongle thing (an improvement, but not a huge one, tbh. seemed to rob some of the life and punch from the music). I then upgraded to a Plixir Elite BDC after not being able to secure a Sean Jacobs or Paul Hynes PS for purchase, new or used (and getting tired of waiting for one to pop-up). The Plixir was an enormous increase in fidelity and is mandatory, IMHO. Just like Jay at AudioBacon, the degree to which it bolsters and reveals the Qutest's true character is hard to digest from a purely logical perspective. However it's a definite "wow" moment for the Qutest. I found Jay's description of the Plixir Elite BDC, with a Qutest, to be spot-on. Though I suspect his Plixir wasn't fully broken-in by the end of his test.

But yes. From a BS Node 2i via USB.... to the Roon Nucleus via USB....to the Denafrips GAIA DDC via USB/BNC.... to Nucleus + Intona USB Isolator..... to adding the SRC-DX (USB -> dual-BNC)....then adding the in-line BNC filters to reduce unnecessary noise....every step made an improvement.

I actually experimented with the BNC filters quite a bit from Thor Labs and MiniCircuits. The tighter you can get from 1Mhz to 100Mhz, as a passband, the cleaner and more organic the sound you get. In my experience. I spent the better part of $1000 USD just in BNC filters to experiment, as an example. There were some theoretical combinations that should have worked, but made getting the signal-lock really unstable, as an example.

In sum, yes...I have experimented extensively.

And, I'll note that the Hugo TT2, while quite a bit better in stock form than the Qutest, and apparently insensitive to PS & upstream USB upgrades/enhancements.....the Qutest had so much more gas in the tank as compared to stock form and responded very well to these upgrades. It's, in my mind, a credit to Rob Watts at incorporating so many genuine improvements into the TT2. Once you start to add up the cost of all these various things....the TT2 isn't a bad value at all.

Though....controversial take: I found my fully hot-rodded Qutest to be slightly better than a TT2 in my system, upon direct comparison. And there was one mod that put that over the top (for another discussion).

 

[20hzFlat]

In stock form, it is very sensitive to the quality of your local mains. I've heard it in 3 different grids across two US States and, with the OEM SMPS, the sound quality in stock form can vary quite greatly in my experience. It could sound slightly thin and etched. But not always. Late nights (with cleaner power) in the PNW always made it sound smoother and more organic. So I am inclined to believe both sides when they say "Qutest sounded like X", because it probably did.

Upgrading to an iFi Elite or Allo Shanti power supply was the first major step in reducing this variability; I settled on the Shanti mainly because it was cheaper and sounded very nearly as good. I then upgraded to an SBooster with the little add-on ultra dongle thing (an improvement, but not a huge one, tbh. seemed to rob some of the life and punch from the music). I then upgraded to a Plixir Elite BDC after not being able to secure a Sean Jacobs or Paul Hynes PS for purchase, new or used (and getting tired of waiting for one to pop-up). The Plixir was an enormous increase in fidelity and is mandatory, IMHO. Just like Jay at AudioBacon, the degree to which it bolsters and reveals the Qutest's true character is hard to digest from a purely logical perspective. However it's a definite "wow" moment for the Qutest. I found Jay's description of the Plixir Elite BDC, with a Qutest, to be spot-on. Though I suspect his Plixir wasn't fully broken-in by the end of his test.

But yes. From a BS Node 2i via USB.... to the Roon Nucleus via USB....to the Denafrips GAIA DDC via USB/BNC.... to Nucleus + Intona USB Isolator..... to adding the SRC-DX (USB -> dual-BNC)....then adding the in-line BNC filters to reduce unnecessary noise....every step made an improvement.

I actually experimented with the BNC filters quite a bit from Thor Labs and MiniCircuits. The tighter you can get from 1Mhz to 100Mhz, as a passband, the cleaner and more organic the sound you get. In my experience. I spent the better part of $1000 USD just in BNC filters to experiment, as an example. There were some theoretical combinations that should have worked, but made getting the signal-lock really unstable, as an example.

In sum, yes...I have experimented extensively.

And, I'll note that the Hugo TT2, while quite a bit better in stock form than the Qutest, and apparently insensitive to PS & upstream USB upgrades/enhancements.....the Qutest had so much more gas in the tank as compared to stock form and responded very well to these upgrades. It's, in my mind, a credit to Rob Watts at incorporating so many genuine improvements into the TT2. Once you start to add up the cost of all these various things....the TT2 isn't a bad value at all.

Though....controversial take: I found my fully hot-rodded Qutest to be slightly better than a TT2 in my system, upon direct comparison. And there was one mod that put that over the top (for another discussion).

Great description. Its interesting, I found the sbooster with ultra add on added life and punch. Systems having varying degrees of how things change certainly seems common. Ive got 2 sboosters plugged into a Isotek Corvus one is for my streamer. I keep meaning to try them straight in the wall just for experiment sake. I also know of folk who have said the same thing about Hot-rodded Qutest v TT2. I also tried a Lan Filter

 

[hifi-dog]

About the Qutest, I've read somewhere that the 2V and 1V option is digitally attenuated. So in essence the 3V option would be for the purist!

All interesting stuff.

I’m not so sure.. there is a massive thread on headfi on the qutest and I’m pretty sure that digital resolution remains and the output stage is padded down.

 

[cb01]

I’m not so sure.. there is a massive thread on headfi on the qutest and I’m pretty sure that digital resolution remains and the output stage is padded down.

Correct, there's no decimation occurring in the Qutest. I.e. you're not losing bit depth going from 3v to 2v to 1v. RW has explained that he does the attenuation in the FPGA and that bit depth resolution at output is exactly the same for all 3 settings.

I have used the 1v setting for years and, all the times I have A/B'd it with 2v/3v, have not bee able to discern a difference I could attribute to the Qutest.

 

[John Phillips]

Anyone any idea where 3V as an acceptable line level came from?

I don’t understand why anyone would want this high a level. It is far higher than most power amps could handle (typically 1-2V) so no advantage when using a passive preamp even into amps at the upper end of the range. The now standard 2V for digital was viewed as too much for many preamps when it was introduced and arguably a key reason people didn’t subjectively like CD as it often subtly clipped their preamp stage leading to a perception of harshness and thinness. I don’t see why the figure seems to be creeping ever upwards. It basically means I can’t use the fixed outs on the DSX.

This is speculation. I suspect the 2 V level for CD players and DACs came about because of the capability of digital audio to represent very low level audio signals.

A higher full scale voltage than previously standard was needed to allow those very low-level signals to stay sufficiently far above the thermal noise floor in an analogue preamp to be clearly audible. A 2 V level allows a good margin for 16 bit audio into a normal preamp input.

And then as the resolution of DACs got better some makers succumbed to the temptation to raise that 2 V to get the highest possible dynamic range. Even well above what is really needed for music but looking good on the spec sheet.

 

[20hzFlat]

Correct, there's no decimation occurring in the Qutest. I.e. you're not losing bit depth going from 3v to 2v to 1v. RW has explained that he does the attenuation in the FPGA and that bit depth resolution at output is exactly the same for all 3 settings.

I have used the 1v setting for years and, all the times I have A/B'd it with 2v/3v, have not bee able to discern a difference I could attribute to the Qutest.

I have done exactly the same and fully agree. It was merely adjusting the sensitivity of the volume control on the amp and how much you turn the dial to achieve the same volume.

 

[martin clark]

@John Phillips

I concur, exactly that.

Many of the favoured, low price but apparently-excellent DAC & headphone amps that are praised over on ASR have as much as 4-5vrms outputs, yet the hallowed (there) SINAD measurement does not correct for such, to say a constant 2Vrms per redbook, to allow true comparisons to be made over time. That's up to a 6-8dB 'advantage' sneaked into plain sight - or rather, plain-overlooked in the regime.

So - let us play that game. 'My' headphone amp was tested by stereophile c 1995 at -108dB SNR relative to 1V output.
Hey, that also means today it's right at -121dB SNR at 5v output... take that, suckers (PS: collect remaining bits of your own eardrums on the way out, please..)


Lies, damn lies, and statistics... 'in matters of music, for judgement, ultimately everything comes to the ear.' - said Lord Kelvin, at least 140yrs ago. I cannot argue with a word of that.

 

[20hzFlat]

There really is no point in continuing this other to note that you joined this forum on April 1st and ask if that is relevant , but seriously, best wishes but over and out.

I apologise for the blunt attitude. I thought you were another one of these folk that will argue black is white. I'm sure youve seen them as well. I came out all guns blazing to nip it in the bud and shouldnt have.