[Deftone]

I tried in the last days the optical and USB and for me they do not sound in the same way. But first to explain the environment:
1) source 1 is a PC with Foobar and ASIO where I play FLAC files, connected to Qutest via a 3m QED Reference USB A-B cable
2) source 2 is a CXC (CD transport), connected to Qutest via a 1m QED Reference Quartz optical cable
Both inputs are connected at the same time, and I switch the input via the button. Qutest is connected via RCA to a tube Amp.
I tried the same CD in the CXC from which I encoded the FLAC files. So we have the same album, the same DAC and the same AMP and I use the same headphones (T1.2).
Normally, we would expect to have minimal differences, and almost the same sound on both, right? But for me the optical input sounds darker than the USB. And the difference is not subtle.
So I guess the only difference can be the jitter on USB, since the optical has to be "isolated" from the electrical interference.
Other factor might be that the PC is plugged in a normal power outlet while the CXC is plugged (alongside the tube amp) in a Furman power conditioner which has to provide a better AC filtering than for the PC.
If I am wrong in my assumptions please correct me. Anyone tried such an 1:1 test with COAX?

It’s not the jitter on the USB for 2 reasons. One, the USB timing is asynchronous, meaning the timing comes from the DAC so there should be zero jitter. Two, Rob’s designs are jitter immune on all inputs due to the Pulse Array design. Likely you are hearing the difference from RF noise being injected in to the analogue components with USB making it sound brighter. As you rightly mentioned the optical is electrically isolated so does not transmit the RF noise so this is the most likely reason why it sounds darker, as Rob has explained many times.

I think it is some type of noise because my high power pc gives sibilance with usb but none when using optical

 

[MagnusH]

USB cables seems to matter for all DACs, but how about optical? Does cables matter for toslink? I think Rob said that toslink was source independent, which should mean cables don't matter. But has anyone tried and experimented?

 

[betula]

Many people say, Qutest is for speakers.
I think Qutest is the best DAC under £2000 for any purpose.

Folks tell me I should swap Qutest for Hugo2 for headphone listening. I don't agree. I think Qutest paired with TOTL headphone amps perform better. Until I can pay for TT2.

I am very happy with my CMA600i balanced out. I actually prefer this to iFi Pro iCan.
I am curious however to try Violectric V281 or can't wait for Headamp GSX-mini. Both could be fun until I can afford TT2.

 

[Hoobi]

Stock USB cable is good like stock power supply one like it, one not even without sound impact, just for good feeling. It's important, after all....

 

[lukeslens]

I'm curious about how well the Qutest does with separation considering its unbalanced option only? I've become quite accustomed to how powerfully defined the separation can be when using my Focal Clears in a fully balanced mode. It's made using them balanced almost a requirement for me cause the separation is so intoxicating!

I was going from a Teac UD-501 into a Loxjie P20 and was just blown away by what I was hearing. Then I attempted to upgrade to the CMA600i to regain some of the detail I was losing with the P20, expecting that to be an upgrade (even though it doesn't offer balanced inputs for a separate dac) and am admittedly disappointed in the outcome to be honest. Was looking at a Qutest because I honestly love the musical sound signature of the Chord products but worried that I'm never going to quite get that dynamic separation I had again until I'm in a fully balanced configuration once more (balanced dac > balanced headphone amp). So really wondering if anybody who has experience with both that kind of set-up plus the Qutest can attest to the quality there and if you lose some of that by being restricted to its unbalanced outputs?

My alternative is to just go with something like an ADI-2 into a tube amp to try to reclaim some of the coloration I prefer with the Clears.

 

[miketlse]

USB cables seems to matter for all DACs, but how about optical? Does cables matter for toslink? I think Rob said that toslink was source independent, which should mean cables don't matter. But has anyone tried and experimented?

Some owners use the terms SPDIF and optical interchangeably, when talking about cables.
The SPDIF standard applies to both optical and coaxial cables.
In this case we are just talking optical.
The FAQ in post #3 of the mojo thread contains some useful generic information about optical cables.
I like quite a few other posters use kabeldirect cables which are quite cheap.
They provide good performance at CD quality file bitrates.
If I found that they could not handle HiRes files, I would consider changing to glass fibre based cables - otherwise, there is no need to pay hundreds of dollars to explore optical as an input for Chord dacs.
YMMV if you prefer to pay more money.

 

[Nautrachkfriend]

I'm curious about how well the Qutest does with separation considering its unbalanced option only? I've become quite accustomed to how powerfully defined the separation can be when using my Focal Clears in a fully balanced mode. It's made using them balanced almost a requirement for me cause the separation is so intoxicating!

I was going from a Teac UD-501 into a Loxjie P20 and was just blown away by what I was hearing. Then I attempted to upgrade to the CMA600i to regain some of the detail I was losing with the P20, expecting that to be an upgrade (even though it doesn't offer balanced inputs for a separate dac) and am admittedly disappointed in the outcome to be honest. Was looking at a Qutest because I honestly love the musical sound signature of the Chord products but worried that I'm never going to quite get that dynamic separation I had again until I'm in a fully balanced configuration once more (balanced dac > balanced headphone amp). So really wondering if anybody who has experience with both that kind of set-up plus the Qutest can attest to the quality there and if you lose some of that by being restricted to its unbalanced outputs?

My alternative is to just go with something like an ADI-2 into a tube amp to try to reclaim some of the coloration I prefer with the Clears.

You do not miss out on much with the unbalanced outs on the Qutest. I've run fully balanced setups and honestly I can't tell any sort of difference between the fully balanced setups vs the unbalanced output on the Qutest. The unbalanced output on the Qutest is designed very well so you really aren't missing much vs a traditional fully balanced setup except for maybe some extra volume. Heck I've had a more expensive, highly regarded, fully balanced dac that didn't even sound as good as the unbalanced Qutest if that says anything.

It does sound like you would benefit from using a balanced amp with the Qutest that can convert from unbalanced to balanced. I currently run my Qutest to my HPA 4 which takes the unbalanced signal and feeds it into a balanced amp infrastructure so that I can plug my headphones into the 4 pin XLR output on the amp. It might not be technically as good as fully balanced setup but honestly I would never be able to tell the difference in a million years.

 

[lukeslens]

You do not miss out on much with the unbalanced outs on the Qutest. I've run fully balanced setups and honestly I can't tell any sort of difference between the fully balanced setups vs the unbalanced output on the Qutest.

That was exactly what I was hoping to hear. I had a Mojo for awhile and did fall in love with the Chord sound and then had a chance to audition the Qutest recently over at Music Direct and though it was only for a good 10 minutes probably, it was giving me what I knew I'm missing in my set-up right now.

 

[Joe-Siow]

USB cables seems to matter for all DACs, but how about optical? Does cables matter for toslink? I think Rob said that toslink was source independent, which should mean cables don't matter. But has anyone tried and experimented?

I'm using the Tellurium Q Ultra Silver USB cable. The guys from Tellurium Q make some great cables. This one has the all the properties of the Black series with slightly more emphasis on details and clarity.
As I'm currently using Black Cat Lupo speaker cables with a special order of mini Stargate incoming, I'd love to try Chris' USB Digit USB cable.

If you looking for optical cables, I'd highly recommend Lifatec glass cables. Always glass over plastic for me.

 

[Sray]

hi everyone,

thanks for helping on the noise issue I reported here.
After some power cycles and cable attach/detach, Qutest can sing without noise. Still, don't know the root cause. I will exam more to figure out the possible root cause. Will share here once I find it.
thanks.

William

 

[Ragnar-BY]

I'm curious about how well the Qutest does with separation considering its unbalanced option only? I've become quite accustomed to how powerfully defined the separation can be when using my Focal Clears in a fully balanced mode. It's made using them balanced almost a requirement for me cause the separation is so intoxicating!

There are some amps (like HeadAmp GS-X mk2) that require balanced input for balanced output. And there amps (like Violectric V2xx) which will give you both outputs with either SE or balanced input. With such amp and interconnects shorter than 2m (maybe even longer, I`m not sure), there is no real need for balanced DAC. Also, good SE amp could easily outperform mediocre balanced amp. I choose Qutest over competitors because for me SQ was more important than additional features. If you like the Chord house sound in general, you would not be disappointed with it.

 

[odessamarin]

I am just wander for how long the dogma about balanced interconnections usefulleness only for long distance will pops up here and there. This is just not true. What is more important here is no crosstalk between channels in compare to the single ended, where it is always present due to the common ground. Now, if one really want to hear it.. you need to go full balanced.. from the DAC to headphones. And don't listen this crap about how single ended can be as good or even better. It could never be by definition. In case both gears is high level.. Once you hear how the soundstage represents with full balanced gears, you can't go back for single ended. And yes even super duper Qutest will sound flat and lifeless. Belave me or not. Mine sold. I can't comment how it goes with speakers though, have no idea about soundstage importance there.. but if you go with headphones. Do your a favor.. do it right. Go balanced and don't think twice. Try, comes back, and say thanks.

 

[Arniesb]

I am just wander for how long the dogma about balanced interconnections usefulleness only for long distance will pops up here and there. This is just not true. What is more important here is no crosstalk between channels in compare to the single ended, where it is always present due to the common ground. Now, if one really want to hear it.. you need to go full balanced.. from the DAC to headphones. And don't listen this crap about how single ended can be as good or even better. It could never be by definition. In case both gears is high level.. Once you hear how the soundstage represents with full balanced gears, you can't go back for single ended. And yes even super duper Qutest will sound flat and lifeless. Belave me or not. Mine sold. I can't comment how it goes with speakers though, have no idea about soundstage importance there.. but if you go with headphones. Do your a favor.. do it right. Go balanced and don't think twice. Try, comes back, and say thanks.

Do you understand that Its Amp design that can benefit from balanced inputs or not. There is much more Amps that Convert signal to balanced Like Headamp Mini, V281 and many more. For Headamp GSX mk2 it matters cause it convert signal.

 

[Ragnar-BY]

I am just wander for how long the dogma about balanced interconnections usefulleness only for long distance will pops up here and there.

I think it will pop up for a long time. Just because it`s true Balanced lines solve some problems. Not all setups have those problems.

And don't listen this crap about how single ended can be as good or even better. It could never be by definition. In case both gears is high level..

You can read Hugo TT2 thread and see what Rob says about balanced and SE outputs in Hugo TT2. I assume, nobody would argue that TT2 is a "high level" device.

 

[odessamarin]

Do you understand that Its Amp design that can benefit from balanced inputs or not. There is much more Amps that Convert signal to balanced Like Headamp Mini, V281 and many more. For Headamp GSX mk2 it matters cause it convert signal.

I am not talking about convertion amps here. Do I? What I say is once you hear full balance gear as it has to be.. literally two full amps in one, one full amp per channel. And if it appropriate calibrated (bias adjusted), you will never accept single ended scheme compromise. Just this. What ever who say what. You hear it.. done. Technically it superior, channel isolation is superior, scene is as it has to be. Deep, wide, tall. It will be all around you. It's like you discover whole new dimension.
My advice to everybody, don't lose time and money for SE solution. You will regret after you hear balanced. If not, means you never ever will heard what i am talking about, Which would be sad, but fine.


@Ragnar-BY

"The special feature of the combination of a balanced amp with a balanced headphone is the superb channel separation. I want to state that also the channel separation of “normal” headphones and amps is much better than most program material. So there are not many complaints about – maybe because most users don’t know about the better way… Sometimes even the high channel separation of normal amps is perceived as not normal and reduced artificially by “cross-feed” circuitries. But the optimized channel separation and low intermodulation are often responsible for the “whow” feeling which many first-time listeners have with balanced headphones. To say it in a striking manner: Hearing with loudspeaker is like sitting in the audience, hearing with headphones is like taking the place of the conductor. Hearing balanced means being part of the orchestra...."

some good reading
http://violectric-usa.com/download/Balanced Headphone Amplifier Explained.pdf