Chord Qutest

[ecwl]

Wow. I can’t believe this PSU thing is generating so much controversy. I don’t own a Qutest. Half the time, when Rob Watts writes something on Head-Fi, I don’t really understand what he’s saying. Takes re-reading it several times and thinking about it to understand a little more. Moreover, he changes his mind over time. Or he would say, he was expecting other people to use better source components or pre-amp/amp so the problem is not with Chord products/supplied PSUs but he acknowledges that a problem can exist.

 

Going to Head-Fi and reading Rob Watts thoughts, the following is what I got even though I understood like 30% of what he’s saying:

there is no ground with the supplied Qutest PSU; and that is done on purpose, as it eliminates the possibility of ground loops.
for sure ground loops are the major issue, as it's a low impedance direct connection. The problem with a non ground connected PSU is much smaller again, as it is capacitively coupled to the mains and then to ground via the PSU transformer; so here we have the possibility of another loop; but it's capacitive, so only applies with RF signals, not leakage currents in the audio bandwidth. Clearly having as low as possible mains coupling capacitance will be good; so we need a PSU that has a low interwinding transformer capacitance - and guess what, the lowest capacitance are found on those awful SMPS - those pesky small mickey mouse things that audiophiles think are poor.
Also - the capacitive problem only applies at RF, and guess what - you can use RF filters to further isolate the effects of the coupling capacitance - I have proven this via SPICE modelling, an RF PSU filter can be made to isolate the capacitive coupling to ensure that the mains loop is broken - no RF current can flow via this loop. and Qutest is full of RF filters to isolate the RF and capacitive coupling from the mains.
To get rid of RF you must have effective RF filtering, and that means a complex multistage filter. But even simple SMPS filters are better than no filters that are often in linear PSU's.
The hard bright sound is characteristic of more random RF noise entering your system, creating more noise floor modulation, which makes it sound brighter, and if bad, harder and grainy.

But if you are worried about the mains loop then a simple way is to use a USB battery power pack. That will completely eliminate the issue, as it's totally isolated from the mains. My own listening tests revealed tiny differences by replacing the Qutest PSU with a battery - but that was with my setup so YMMV.

The one I use is Poweradd Pilot Pro2. Now this has internal regulators - so it is noisy on the OP - but the key is the absence of mains bourne RF noise. With Hugo 2, adding the unit makes no difference to the SQ, and it's the issue of RF noise that is key, not the noise on the OP. Also, it's completely isolated from the mains, so no ground loops or leakage current is possible.

Like I said, I don’t even fully understand most of this. And in other posts, Rob Watts has acknowledged that in some systems, the high-impedance leakage current ground loop noise can play a role in the sound. 

So my take is that obviously, with a linear power supply for Qutest, you’re going to get less high-impedance leakage current ground loop noise in your system if it’s in other components’ PSUs. So you might like the sound more with LPSU and Qutest in your system because of this. Alternatively, you might just like more RF from the LPSU creating a brighter sound. Or as some have said, there are LPSUs and then there are really good LPSUs that might actually address Rob Watts’ concerns. It would be great if someone with more expertise on LPSUs actually address Rob Watts’ comments instead of a blanket “battery better” or “LPSU better“ or “stock SMPS better”. Otherwise, it just sounds like we are just cheering for our favourite sports teams (not that there is anything wrong with that, I guess).

 

[kennyb123]

2 hours ago, ecwl said:

Like I said, I don’t even fully understand most of this. And in other posts, Rob Watts has acknowledged that in some systems, the high-impedance leakage current ground loop noise can play a role in the sound. 

So my take is that obviously, with a linear power supply for Qutest, you’re going to get less high-impedance leakage current ground loop noise in your system if it’s in other components’ PSUs. So you might like the sound more with LPSU and Qutest in your system because of this. Alternatively, you might just like more RF from the LPSU creating a brighter sound. Or as some have said, there are LPSUs and then there are really good LPSUs that might actually address Rob Watts’ concerns. It would be great if someone with more expertise on LPSUs actually address Rob Watts’ comments instead of a blanket “battery better” or “LPSU better“ or “stock SMPS better”. Otherwise, it just sounds like we are just cheering for our favourite sports teams (not that there is anything wrong with that, I guess).

 

 

It almost inevitably gets into a circular do-loop when it comes to Rob and power supplies.  When a claim is made that power supplies make a bigger difference than Rob allows for - that’s equivalent to suggesting that maybe Rob isn’t fully accounting for how certain better power supplies benefit digital products.  I’m not sure what sense it makes to quote Rob and rephrase what’s going on in terms of how he thinks about these things.  
 

Rob’s will often put forth the (unfair) argument that if you find a benefit in something that he says shouldn’t matter then it’s because you prefer the sound of RF.  I’m paraphrasing of course but ecwl captures the spirit of it well above with “alternatively, you might just like more RF from the LPSU creating a brighter sound.”  This is unfair because it ignores the other reasons why someone might prefer a LPS, like maybe the fact that it has an exceptionally low impedance so it doesn’t sag under instantaneous current demands.  That’s an important quality and something the really good power supply designers consider to be of the utmost importance.  I love Rob to death as his designs bring me joy every day, but I have to say that when it comes to power supplies, it’s almost like Rob plays 2D chess while guys like Paul Hynes, Sean Jacobs and John Swenson are playing 3D chess.

 

In fairness I’m playing checkers relative to all of them.  All I know is that the improvements I hear from using Farad Super3s in place of the supplies Rob selected are as profound as I’ve heard from any upgrade.  The guys playing 3D chess wouldn’t be surprised at all either - and neither would be most of the folks here who have tried well-regarded power supplies.
 

To ecwl’s last point, I do see occasional generalizations but that’s the norm amongst us guys playing checkers.  On the other hand, I do think that the important considerations about power supplies have been addressed repeatedly in other threads by folks far more knowledgeable than me - from really smart guys like Barrows for example.  I get the sense also that these guys don’t pay much mind to what Rob says about power supplies as their own experiences tell them that he may have a blind spot there.  Again, I’m not trying to beat up on Rob - he’s a freaking genius.  But he’s human just like the rest of us and that means he’s not omniscient. 
 

[feelingears]

58 minutes ago, kennyb123 said:

I get the sense also that these guys don’t pay much mind to what Rob says about power supplies as their own experiences tell them that he may have a blind spot there.  Again, I’m not trying to beat up on Rob - he’s a freaking genius.  But he’s human just like the rest of us and that means he’s not omniscient. 
 

 

"The dogma is strong with that one..." 😉

 

There's another well-known and very successful audio company that makes great products but eschews commentary on what we as their consumers, hear or don't hear. Just as well, and yet because of how prominent they are, and because of how their demographic is influenced by them, I wish they would "care" about power and cables as much as the more discerning ears here do. Regrettably, we're all simply human and they have their blind spots as we all do.

 

My dogma: Everything counts in large amounts, and clean power uber alles, and YMMV. 

 

When I try a Qutest someday, it will be with "audiophile-grade" power. Nothing to fear but hearing itself. 😀

[Richard Dale]

4 hours ago, ecwl said:

Wow. I can’t believe this PSU thing is generating so much controversy. I don’t own a Qutest. Half the time, when Rob Watts writes something on Head-Fi, I don’t really understand what he’s saying. Takes re-reading it several times and thinking about it to understand a little more. Moreover, he changes his mind over time. Or he would say, he was expecting other people to use better source components or pre-amp/amp so the problem is not with Chord products/supplied PSUs but he acknowledges that a problem can exist.

 

Going to Head-Fi and reading Rob Watts thoughts, the following is what I got even though I understood like 30% of what he’s saying:

there is no ground with the supplied Qutest PSU; and that is done on purpose, as it eliminates the possibility of ground loops.
for sure ground loops are the major issue, as it's a low impedance direct connection. The problem with a non ground connected PSU is much smaller again, as it is capacitively coupled to the mains and then to ground via the PSU transformer; so here we have the possibility of another loop; but it's capacitive, so only applies with RF signals, not leakage currents in the audio bandwidth. Clearly having as low as possible mains coupling capacitance will be good; so we need a PSU that has a low interwinding transformer capacitance - and guess what, the lowest capacitance are found on those awful SMPS - those pesky small mickey mouse things that audiophiles think are poor.
Also - the capacitive problem only applies at RF, and guess what - you can use RF filters to further isolate the effects of the coupling capacitance - I have proven this via SPICE modelling, an RF PSU filter can be made to isolate the capacitive coupling to ensure that the mains loop is broken - no RF current can flow via this loop. and Qutest is full of RF filters to isolate the RF and capacitive coupling from the mains.
To get rid of RF you must have effective RF filtering, and that means a complex multistage filter. But even simple SMPS filters are better than no filters that are often in linear PSU's.
The hard bright sound is characteristic of more random RF noise entering your system, creating more noise floor modulation, which makes it sound brighter, and if bad, harder and grainy.

But if you are worried about the mains loop then a simple way is to use a USB battery power pack. That will completely eliminate the issue, as it's totally isolated from the mains. My own listening tests revealed tiny differences by replacing the Qutest PSU with a battery - but that was with my setup so YMMV.

The one I use is Poweradd Pilot Pro2. Now this has internal regulators - so it is noisy on the OP - but the key is the absence of mains bourne RF noise. With Hugo 2, adding the unit makes no difference to the SQ, and it's the issue of RF noise that is key, not the noise on the OP. Also, it's completely isolated from the mains, so no ground loops or leakage current is possible.

Like I said, I don’t even fully understand most of this. And in other posts, Rob Watts has acknowledged that in some systems, the high-impedance leakage current ground loop noise can play a role in the sound. 

So my take is that obviously, with a linear power supply for Qutest, you’re going to get less high-impedance leakage current ground loop noise in your system if it’s in other components’ PSUs. So you might like the sound more with LPSU and Qutest in your system because of this. Alternatively, you might just like more RF from the LPSU creating a brighter sound. Or as some have said, there are LPSUs and then there are really good LPSUs that might actually address Rob Watts’ concerns. It would be great if someone with more expertise on LPSUs actually address Rob Watts’ comments instead of a blanket “battery better” or “LPSU better“ or “stock SMPS better”. Otherwise, it just sounds like we are just cheering for our favourite sports teams (not that there is anything wrong with that, I guess).

 

Interesting comment about the Qutest earthing. My 2Qute has a grounding post and the MCRU linear power supply that I use with it, comes with a DC lead that has an earthing fly lead, and so I connect that to the grounding post. I assume the Qutest doesn’t have an grounding post.

[barrows]

Qutest is designed to be left floating (RE power supply), this can still be achieved through an appropriately designed linear power supply.  In this case it will still be grounded, eventually, by whatever the RCA outputs connect to.  My understanding is that Qutest has an isolated USB input, so there should not be any worries about a loop as the only ground will be via the RCA return/shield connection.

[Gavin1977]

I tried a DAVE, technically perfect, but I didn't like it as the soundstage was way too set back for my liking. I now have the qutest. Works better for me in the fact that everything is somewhat more upfront and vocals have presence (slightly more forward?).

I do find it a more darker sounding DAC than the DAVE though, the highs are also somewhat recessed, and this decreases it's realism IMO. I use the incisive neutral filter and Oyaide Tunami Terzo RR v2 and Sablon 2020 USB.

I previously found the tonal balance of the Yggy about perfect, but the noise floor of that DAC was not good enough for me.

Any tips on how to tune the qutest to my taste - upsampling, use spdif instead of USB, external linear power supply? Any thoughts?

[fds]

Will be interesting to hear your impressions when comparing the Qutest to your DAC8DSD. I have a Chord Mojo here and I found it to be somewhat faster than the DAC8DSD with somewhat better soundstage depth. Also the Mojo was clearly thinner sounding with much less density and thereby maybe a tad more transparent on complex pieces. However, I did compare them only at the very beginning when the DAC8DSD was not yet burned in. Should do another comparison now.

 

 

 

 

 

 

[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).

 

[ecwl]

10 minutes ago, Gavin1977 said:

I previously found the tonal balance of the Yggy about perfect, but the noise floor of that DAC was not good enough for me.

Any tips on how to tune the qutest to my taste - upsampling, use spdif instead of USB, external linear power supply? Any thoughts?

Are you playing bit perfect original source to Qutest? Or are you using HQPLAYER and if so what type of upsampling are you doing?

[fds]

When I use HQPlayer with the Mojo, I find the sinc-M, sinc-L, etc. to be the best choice. In fact, my feeling was that, e.g., poly-sinc-ext2 does spoil the striking temporal accuracy of the Mojo to some extend. I expect the same to hold for the Qutest ... will be interesting to read more from @Gavin1977 about his impressions/settings.

[ecwl]

6 minutes ago, fds said:

When I use HQPlayer with the Mojo, I find the sinc-M, sinc-L, etc. to be the best choice. In fact, my feeling was that, e.g., poly-sinc-ext2 does spoil the striking temporal accuracy of the Mojo to some extend. I expect the same to hold for the Qutest ... will be interesting to read more from @Gavin1977 about his impressions/settings.

Haha... HQPlayer has been bragging about how much better it is than Chord DACs for years. So I would try it and then find it lacking and then a few years later, do it again and still be underwhelmed. The last time I tried it was when poly-sinc-ext2 was available but before sinc-M/sinc-L because even back then HQPlayer was claiming that poly-sinc-ext2 is far superior to M-scaler+DAVE. What a joke. Poly-sinc-ext2 was at best a toss-up for me vs the Mojo.

 

That said, for people who don't have Chord DACs, I do think HQPlayer is a great product and I see the fact that every year there are new filters shows a commitment to excellence. On the other hand, I don't like being a free beta tester so I don't have a license to the product to re-test.

[Gavin1977]

I'll try these suggestions and report back...  SPDIF is first on the list.

[MarkusBarkus]

53 minutes ago, Gavin1977 said:

I do find it a more darker sounding DAC than the DAVE though, the highs are also somewhat recessed, and this decreases it's realism IMO. I use the incisive neutral filter and Oyaide Tunami Terzo RR v2 and Sablon 2020 USB.

I found the same to be true when I used the Qutest. I preferred the incisive neutral filter most of the time. Interestingly, I also used a Tunami, but the red-plug version. USB was Triode Wire Labs.

 

I *really* liked the Qutest. It was part of my plan to see if I liked the "Chord Sound." 
 

I did. So, I added an MScaler to the Qutest. That was really excellent, IMO and I could have lived with that.

 

But hobbies (aka: addictions) being what they are, the march to DAVE unfolded. Now I have a DAVE on a DC4. 
 

I like the D/DC4 a lot, but frankly, that Qutest MScaler config was really sweet.
 

For the first month on the DAVE/MScaler I wondered if I had misstepped. The uber set-up is clean and revealing, but the Qutest is very musical. Very nice.
 

BTW: the Wave BNCs are good for sound too. I have the mid-level version. Good luck!

[barrows]

1 hour ago, ecwl said:

On the other hand, I don't like being a free beta tester so I don't have a license to the product to re-test.

That is funny: I have never heard of anyone being paid, or receiving any special favors for beta testing.

[barrows]

1 hour ago, Gavin1977 said:

I tried a DAVE, technically perfect, but I didn't like it as the soundstage was way too set back for my liking. I now have the qutest. Works better for me in the fact that everything is somewhat more upfront and vocals have presence (slightly more forward?).

I do find it a more darker sounding DAC than the DAVE though, the highs are also somewhat recessed, and this decreases it's realism IMO. I use the incisive neutral filter and Oyaide Tunami Terzo RR v2 and Sablon 2020 USB.

I previously found the tonal balance of the Yggy about perfect, but the noise floor of that DAC was not good enough for me.

Any tips on how to tune the qutest to my taste - upsampling, use spdif instead of USB, external linear power supply? Any thoughts?

My brother owns the Qutest: I designed a really nice linear supply for him to use with it and he reports a substantial performance improvement with that.  IMO, the Qutest is begging for a better power supply and that upgrade is a simple no brainer.  As it has only RCA outputs, different cables will also make substantial differences in sound (RCA cables make for bigger differences than do balanced cable swaps), so it might be worth trying various cable options-the Cable Company lends cables to try.

[ecwl]

14 minutes ago, barrows said:

That is funny: I have never heard of anyone being paid, or receiving any special favors for beta testing.

Also funny, I have never heard of people having to pay HQPlayer or any other software company $300 to have the "privilege" to be a repeated beta tester for them.

 

Look, the issue is this. HQPlayer has been claiming for years that it is better than M-Scaler/DAVE. So most of us would expect the developer to have actually owned an M-Scaler/DAVE and then compared HQPlayer to the product and then explain why the software is better. We don't expect the developer to just make these bold claims, and then customers download the free trial and then make the comparison and be completely underwhelmed. And then when people like me give that kind of feedback on this forum, the developer goes back to the drawing board, develops better filters which is great for customers, and then comes back and make the same bold claims again and try to sucker other M-Scaler/DAVE owners to make the comparisons again.

 

If the developer is serious about having users beta test their product against other products, they would offer the software for free (perhaps for a limited time) to current owners of competing products to make the comparisons and give them feedback. Or alternatively, an ethical developer would not randomly make these bold claims that their software is superior to specific DACs out there if they didn't test it themselves. They would just say they believe their technology is superior than other products because of specific reasons, perhaps explain why sonically they believe their products are superior and then let customers decide whether to pay for the software to test for themselves.

[ASRMichael]

I think the question of Dave+Mscaler v Dave+HQP comes down to the quality of the server that is being used for HQP. Extreme users here have sold their Mscaler, they now use HQP. Why? Because HQP is so close in quality, and has more options/flexibility. Now that’s probably because they have an Extreme!  Probably doesn’t apply to most other servers. You’ll only know if you test both! 

[ecwl]

24 minutes ago, ASRMichael said:

I think the question of Dave+Mscaler v Dave+HQP comes down to the quality of the server that is being used for HQP. Extreme users here have sold their Mscaler, they now use HQP. Why? Because HQP is so close in quality, and has more options/flexibility. Now that’s probably because they have an Extreme!  Probably doesn’t apply to most other servers. You’ll only know if you test both! 

Truth be told, I wouldn’t be surprised if HQP is now superior to M-Scaler. I would say on the Head Fi forum, maybe up to 50% of posters with M-Scaler prefer HQP. I just don’t feel like wasting my time to test it because I’ve done my fair share of this in the past. For reasons I have described. 

[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...

 

 

[ray-dude]

Having spent a lot of (free) time on this, I would say that HQP is better than mScaler in some ways, and worse in others.  Over time, the areas that it is better has improved, and the areas that it is worse has stayed static.  Both Jussi and Rob are 100% right, Rob just uses better maths, and Jussi uses more maths.

 

Back in Nov 2019, HQP was close enough to mScaler that I decided to "burn the ships" and commit to the software upsampling path, just because I saw way more potential upside on that path.  Since then, it has taken off way more than I expected it ever could, and I haven't looked back (even with NUC...this was pre Extreme).

 

I will confess that when I listen to HQP today (mainly for streaming) the areas where it is worse than mScaler do sometimes gnaw at me.  That being said, I respect that HQP is primarily targeted to DSD upsampling, and us PCM/Chord guys are an outlier use case (thanks to Jussi for accommodating us guys).  I am a very happy customer of HQP and recommend it 100% to all Chord owners, but there is still more SQ improvement to be had.

 

[davide256]

28 minutes ago, asdf1000 said:

 

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...

 

 

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

[barrows]

6 minutes ago, davide256 said:

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

Very doubtful.  Rob Watts has mentioned a number of times how much RF noise is created by the Mscaler, and how important it is to have the Mscaler in a separate chassis form the DAC because of this noise.  Either way, there are issues of heavy processing creating a lot of noise, and isolating the DAC from that noise becomes a priority.  It is arguably more effective to isolate that RF noise by having the component doing the heavy processing well away from the audio system, and connected to the audio system via Ethernet (NAA in HQPlayer's case), and even better, having optical Ethernet isolation.

I am not aware of any real difference between doing the processing on an FPGA or a DSP chip like an AD SHARC, or in a  MoBo processor like an I9 is going to make any difference in reality.  But I am aware of the advantages of isolating the hardware doing the processing form the audio system.

[Gavin1977]

Owning a T+A DAC8 DSD I can say with confidence that HQPlayer works best with the ‘DSD direct’ approach.  Definitely recommend in this application (or R2R/multi-bit).

 

Chord DACs aren’t as transparent to HQPLAYER upsampling IMO.  I have owned Hugo, Mojo, Hugo TT, Hugo 2 and tried the DAVE so I don’t think it will be any different with the qutest.

 

However, HQPLAYER embedded is a great uPNP endpoint.  Works well for me so that’s why I’m also using it with the qutest.

 

Presently no upsampling used within my test, but I will try again.

[ray-dude]

In addition to the very important noise differences, software pipelines tend to have higher bit precision and can handle more compute than FPGA pipelines.  There is simply more brute force available to software than a FPGA, and the (easier) option to do preprocessing of the file.  Good maths in software can do a lot more than good maths in FPGA (for this type of maths).  It takes a LOT of effort to narrow down to what maths are "good", which is where Rob has gotten it right (IMO)

[ecwl]

34 minutes ago, Gavin1977 said:

Chord DACs aren’t as transparent to HQPLAYER upsampling IMO.  I have owned Hugo, Mojo, Hugo TT, Hugo 2 and tried the DAVE so I don’t think it will be any different with the qutest.

 

Presently no upsampling used within my test, but I will try again.

Sorry... When you use HQPlayer upsampling to Chord DACs, what are you upsampling to?

Is it 768kHz or are you using the HQPLAYER DSD upsampling?

And out of curiosity, which upsampling filter do you like? It sounds like most people are using Sinc-M with LNS15 to 384/768kHz for R2R or Chord DACs? But I'm not totally sure because I don't follow HQPLAYER closely.