Chord Qutest

[asdf1000]

3 hours ago, ElviaCaprice said:

If Chord went this route, direct on the DAC, I'd dump them in a second. 

 

Do you mean if a networked connection was the ONLY input?

 

Or you still wouldn’t support Chord if this input was added as standard in future, alongside existing inputs?

 

[asdf1000]

7 hours ago, barrows said:

In my system, there is no ground continuity between the USB ground,

 

Hey barrows, how? An Intona type isolation method?

 

[asdf1000]

48 minutes ago, barrows said:

An isolated USB receiver inside a DAC isolates the USB receiver circuitry and incoming ground of the source

 

Is this part of newer XMOS USB interfaces? Integrated?

[asdf1000]

14 minutes ago, barrows said:

No, what I am describing is the commonly used isolated USB receiver circuit for a DAC.  XMOS is just a USB receiver chip, not a circuit.

 

Ahh ok got it, thanks

[asdf1000]

On 06/05/2018 at 2:02 AM, barrows said:

The power supply design and I/V (in the case of Sabre) or analog output stage will have more influence on the sound than the conversion chip.

 

But, Chord does things quite differently.  I have listened to both Mojo and DAVE, and it is clear to me that Chord is onto something with their approach (wish I could afford DAVE here!).  As their DACs combine both super high resolution playback with a lack of artifacts which is quite stunning to me.

 

For others, some posts from Rob Watts about how/why he does things a bit differently, especially the output stage:

 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-26#post-11963747

 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-132#post-12395944

 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-301#post-12838057

 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-94#post-12262339

 

https://www.head-fi.org/threads/chord-electronics-qutest-dac-official-thread.869417/page-3#post-13966089

[asdf1000]

31 minutes ago, dbq5anlxj said:

are you able to play native dsd use this setup? thanks

 

Native DSD only via Windows using the Chord ASIO driver. But....

 

...with all Chord DACs (except Dave) DSD is converted to PCM anyway.

 

 

[asdf1000]

Just now, pl_svn said:

please point to an official statement or evidence of the above!

 

Fortunately, you can ask the DAC designer directly yourself, by joining this thread:

 

https://www.head-fi.org/threads/chord-electronics-qutest-dac-official-thread.869417/

 

You can get the information straight from the horse's mouth, so to speak.

 

Then you don't need to believe what anyone else says

 

If you're lazy, you can trust me because I've already done all the above ?

[asdf1000]

3 minutes ago, pl_svn said:

been on that thread since the beginning and never read what you are stating

even asked already

 

Hehe I never said the answer is there. I said you can ask him directly there ?

 

[asdf1000]

You could say I'm spreading rumours. Or you could say I'm helping you with exactly how and where to find the confirmation - from the designer himself.

 

It's been asked on numerous Chord DAC threads, not just Qutest.... even before Qutest... The search function is your friend.

 

You can ask him, he's a nice guy, don't be shy ?

 

[asdf1000]

3 minutes ago, pl_svn said:

works the other way around: whom makes a statement has to provide evidence of it

and you are still refusing to 

 

Sigh.

 

@ecwl was nice enough to use the search function for you.

[asdf1000]

2 minutes ago, pl_svn said:

always has and still works the other way around, when making statements @Em2016

 

I can't share information I had from a private conversation I had with Rob because I didn't record it sadly.

 

Anyway the answer was on the thread you linked. You just had to read the thread ?

[asdf1000]

On 7/24/2018 at 8:51 AM, Superdad said:

 

Please remember that all DACs with digital isolator chips ("galvanic isolation") place them on the I2S lines AFTER the USB input PHY/processor.  Hence noise and leakage still affect the USB input stage.

Only current exception to this is the new $5,700 Auralic Vega G2--and some of PeterSt.'s Phasure NOS1a DACs. Those both use the same Silanna USB isolation chip--right at the input--as we use in the ISO REGEN.

 

The new iFi Pro iDSD? Or have they gone a different direction from their iGalvanic (which uses the same Silanna isolator)?

 

[asdf1000]

12 hours ago, Superdad said:

 

Based on photos of the boards that turn up in a Google search, it seems clear that the Pro iDSD has its digital isolator chips on the I2S/DSD lines at the output of their input board—just as is done with many other DACs/DDCs.  Nothing wrong with that.  Just means that the USB input stage still shares the same ground domain with the computer—unless one adds a GI device before the DAC.

 

Noted.

 

They do say: "The USB input section has its own separate power management system with multiple regulators and filtering operating from the galvanically-isolated voltage generated to power this section."

 

I would assume this helps but as you say, better off blocking the leakage currents from getting in, in the first place.

[asdf1000]

3 hours ago, Miska said:

 

Why would that matter as long as the clock is at the DAC side? USB interface just shovels data around and clock should run at the DAC side, on the other side of the isolation barrier. That way whatever happens at the USB side doesn't matter as long as there's no data corruption.

 

 

Is it more to do with blocking leakage currents, which may affect analogue components (RF conducted and radiated) downstream of the DAC?

 

[asdf1000]

3 hours ago, Miska said:

No, this about the case where USB controller is at the USB bus side and isolated from the DAC side which has the clock so there are not leakage currents or effects on the clocking and no effects on the data.

 

But you are only talking about leakage currents affecting the clocking.

 

But if I understand both @JohnSwenson and Rob Watts (I could be wrong), the leakage currents are also responsible for RF pickup and radiation, potentially affecting the analogue stage and downstream analogue components?

 

[asdf1000]

5 hours ago, Marco78 said:

question for qutest owners, since it does not have a switch off button, are the LEDs going off after some time or does it remain lit like a Christmas tree all the time ? In the latter case I can't see it as a viable option in a bedroom setup.

 

Have you already tried the following, which is from the manual....

 

[asdf1000]

11 minutes ago, buonassi said:

Is anyone here using their Qutest with DSD?  Any thoughts on how it handles DSD vs PCM?  

 

All Chord DACs other than Dave convert incoming DSD to PCM.

 

Here he discussed Hugo2 but it's the same for Qutest. You can ask him directly on the Qutest thread if you like but Dave is still the only one that doesn't convert incoming DSD to PCM.

 

https://www.head-fi.org/threads/chord-electronics-hugo-2-the-official-thread.831345/page-651#post-13950774

[asdf1000]

5 minutes ago, buonassi said:

feed the DAC what it processes natively.

 

Yep first step is to find out what the DAC is doing internally.

 

Not many people know that all but Dave convert to PCM internally (in the Chord lineup).

 

There are many people on Head-Fi that swear Mojo/Hugo2/Hugo TT etc all sound best when fed DSD via up-sampling software.

 

The info is buried there in the forums but can be easy  to miss without digging around (or just asking Rob directly - he's pretty easy to reach). 

 

[asdf1000]

21 minutes ago, ecwl said:

https://chordelectronics.co.uk/product/qutest/

 

Or more specifically

 

https://chordelectronics.co.uk/wp-content/uploads/2017/01/Windows-10-768KHz-driver.zip

 

Yep it's there on the right @nick77, in case you're wondering...

 

[asdf1000]

On 6/1/2020 at 7:44 AM, barrows said:

I am not aware of any way to transport 104 MHz sample rate to a DAC from a computer: certainly I no of no DAC which can accept an input sample rate of 104 MHz.

 

M-Scaler isn't upsampling to 104 MHz though.. it's upsampling to PCM705/768kHz... the DACs still upsample internally, to 104 MHz.

 

[asdf1000]

2 hours ago, ecwl said:

Specifically referring to the Hugo TT2 and M-Scaler switching power supply (but Qutest has a different one), Rob Watts has also said that he chose that supply because it has the best measured and sound quality performance, measuring similar to battery power supply, even though there is a 100uA leakage current to ground in that power supply.

 

All good points.

 

Also something to consider - he has said linear PSU's MAY be better but MAY also be worse (poor or no RF filtering).

 

Also something to note - Rob can't have possibly measured every linear PSU on the planet when he says his chosen PSU is the best he's measured.

 

 

[asdf1000]

46 minutes ago, Superdad said:

Lots of leakage (common-mode AC traveling over DC connections) from those iFi iPower SMPS units.

 

While leakage is common to all SMPS’s, have you measured the newer iPower X he mentions?

[asdf1000]

10 minutes ago, Gavin1977 said:

use spdif instead of USB

 

Try optical and report back !

 

But make sure you unplug USB completely from Qutest for this test otherwise you defeat the purpose of testing optical  (which is free from RF).

 

[asdf1000]

46 minutes ago, ecwl said:

Look, the issue is this. HQPlayer has been claiming for years that it is better than M-Scaler/DAVE.

 

Where?

 

Jussi says there is nothing special about maths.

 

Rob says he has the best algorithms, so do not use software upsampling before his products.

 

Do you expect either of them to say different? 

 

Better to just listen and discard any comparisons one makes about the other because there will always be strong bias...

 

Rob doesn't know what HQPlayer is doing fully (algorithms) and HQPlayer doesn't know what WTA is doing fully...

 

 

[asdf1000]

6 hours ago, davide256 said:

Could it just be that M-scaler sounds better because its logic is chip based ( firmware) vs software for HQPlayer?

 

Yes but could it be HQPlayer sounds better for the same reason?

 

I think this is a silly game to play. Because it's so subjective...