[TomWoB]

The big question, when we are talking about different quality of input types, is ... at the end, what do we judge

• the input quality of the DAC (Qutest) or
• the output quality of the streaming device ?

I'm still wondering how big these differences "can be" (?). Let's say, we play the same "very good track"

• from a sMS-200ultra via USB and
  
• from an Allo DigiOne via Coax

and listen both with the Qutest. .. and let's assume, the cables and "the whole transport stuff" are good enough that the Qutest can "identity the bit-perfect signal" (after removing the protocol overhead) ... do we really hear a difference? The Qutest will anyway re-clock, oversample, ... this "bit-perfect signal". So Jitter e.g. is not an issue. OK, we have the RF noise, but

• we have galvanic isolation on USB input of the Qutest and
• we have galvanic isolation on Coax output of the DigiOne too

Maybe there is a difference with other DACs, but in case of a Qutest ... can there really be a "audible difference"? I don't know, I never had the possibility for a blind A-B test. As an electric engineer, I assume there is no difference in case of the Qutest could get the "bit perfect signal". We all copy daily a lot of of files with USB-Sticks or via Ethernet ... do we ever had the case that the copy of a file is different from the original ... NO (or very, very seldom in case of internet connection was lost).

Does the type of the S/PDIF transceiver on the source makes a difference? E.g. the DigiOne uses a WM8805 ... do we ever discuss about transceiver quality?

So ... I like my DigiOne and will stay with it ... I will not switch to a DigiOne Signature (for me only a try of Allo to make more money), because I assume with a DAC like the Qutest there will be no audible difference (yes, I read a lot of reviews that there is a difference). But if I check the layout of the "clean side" of both DigiOnes, I can't identify so much difference. OK, the DC-DC converter is gone, but there is a lot of RF filtering on the "clean-side" ... remember Allo reported this all the time before the Signature came out (!) ... and the sMS-200 uses DC-DC converters too ... so what !

So finally, what I want to say is: I believe that the Qutest is "more source independent" than other DACS !

 

[Thenewguy007]

the accuracy of the oscillating crystals (responsible for timing and clocking the audio signal) inside alot of these cheap chinese ddc's leaves alot to be desired.

Too bad there are no external clocks that are in the realm of affordability.

$3,000-$4,000 for the Mutec & SOtM & starting at $1200 for the cheapest Cybershaft. That's more than any DDC, even with an added external power supply, on the market.

 

[musickid]

if the optical source is bit perfect then the source makes no difference. this was confirmed by the designer of qutest Rob. No audible difference at all. external mutec type clocking will harm chord dac operation. its also best to go direct from source to chord dac and avoid ddc's etc. i use my imac optical into mscaler. the key point is that the source must be bit perfect this is essential. also digital phase lock loop make chord dacs immune to jitter. it saves us a lot of money very good.

 

[Arniesb]

Any decrapifier color or ruin signal integrity... 1st of all some these like Jitterbug and signal converters slow down the signal, because these decrapifiers is like brakes to signal... There could be loss of energy in the process and 2nd every power supply there is add their own color to signal.

 

[Clemmaster]

You seem to know what you are talking about!

 

[Sound Eq]

can i ask please what settings you use in audirivana for mac
especially the sox or izotope advanced settings

 

[Chester Rockwell]

Any decrapifier color or ruin signal integrity... 1st of all some these like Jitterbug and signal converters slow down the signal, because these decrapifiers is like brakes to signal... There could be loss of energy in the process and 2nd every power supply there is add their own color to signal.

I’ll admit I don’t have a great deal of knowledge in terms of the physics of electronics, but the above just doesn’t make any sense to me. Maybe you just understand this stuff better than I, but how do you slow down a signal? And in terms of losing energy, surely the signal is either received or it is not?

As I say, might just be a knowledge gap on my part.

I’m also not saying any of these devices do anything positive, I have no idea. It was more the science that confused me.

 

[Ragnar-BY]

As an electric engineer, I assume there is no difference in case of the Qutest could get the "bit perfect signal". We all copy daily a lot of of files with USB-Sticks or via Ethernet ... do we ever had the case that the copy of a file is different from the original ... NO (or very, very seldom in case of internet connection was lost).

File transfer via USB and audio stream via USB are not the same thing. Here is some info about it:
https://darko.audio/2016/05/gordon-rankin-on-why-usb-audio-quality-varies/

 

[Christer]

Have you ever watched a TV where the sharpness and colour settings have been turned up? Some people like their tellies like that but it is not accurate.

I was once made to sit through one of the Lord of the Rings movies at a friends house where he had a new huge TV with the sharpness turned up and all I could see was the horrible digital artifacts due to the artificial sharpening all the way through the movie. I do a lot of work with digital images and overuse of the PhotoShop unsharp mask (which actually applies sharpening) is easy to spot and is horrible.

Interesting comparison between photography and Photoshop and digital sound.

As a photographer I agree that visible pixels can become very disturbing when overdone.
The bigger the sensor and the more pixels you can cram in on that given space the better.
I would guess almost the same applies with digtal bits and sampling rates?
The more bits you have and the higher the sampling rate, the more information you actually capture.
I found it interesting to read Rob's mentioning hearing basically the same acoustic information from a native 768khz test recording as from an M Scaler.
My guess is as in HI RES full format Photography ie 64 bits and the highest possible sampling rates may be what is actually needed to capture all of the very complex information say a 100 men and women in a large symphony orchestra can deliver live.



Too often until getting an Mscaler, digital sound has been a bit like instead of seeing those pixels in badly done photoshop or with images from a low res small sensor camera with lots of noise, I have been HEARING those pixels as junk ,noise artifacts and a general lack of transparency and resolution from most dacs and digital systems.

Qutest also suffers from such disturbing "pixel effects" which tend to almost disappear or are lowered to a very notable degree with M Scaler connected.
But only with well made recordings.
M Scaler can not turn a bad recording into a good one, and Qutest on its own will struggle to do a really good one the justice it deserves imho..
Cheers Controversial Christer getting ready to re-calibrate things against the only true reference today again in a couple of hours.

 

[Arniesb]

I’ll admit I don’t have a great deal of knowledge in terms of the physics of electronics, but the above just doesn’t make any sense to me. Maybe you just understand this stuff better than I, but how do you slow down a signal? And in terms of losing energy, surely the signal is either received or it is not?

As I say, might just be a knowledge gap on my part.

I’m also not saying any of these devices do anything positive, I have no idea. It was more the science that confused me.

I can give example.
Jitterbug make sound rolled off, lifelles all energy is sucked. This is when Signal integrity is compromised and timing is affected.
This mean slower, veiled, lifeless sound. Some people like reduced energy for some reason.
I have Ifi decrapifier too and this thing have something that fix signal integrity and it clearly shows... There is no slowing down or sucked out veiled sound.
Why do you think silver sound faster and leaner than copper? Because it is more conductive and signal reach faster gear thus presenting better timing.

 

[Triode User]

I can give example.
Jitterbug make sound rolled off, lifelles all energy is sucked. This is when Signal integrity is compromised and timing is affected.
This mean slower, veiled, lifeless sound. Some people like reduced energy for some reason.
I have Ifi decrapifier too and this thing have something that fix signal integrity and it clearly shows... There is no slowing down or sucked out veiled sound.
Why do you think silver sound faster and leaner than copper? Because it is more conductive and signal reach faster gear thus presenting better timing.

I cannot tell whether your tongue is firmly pressed in your cheek or not. I suspect not.

I have no idea what this thing is that you call Signal Integrity and which when compromised you say can cause lifeless sound, all energy is sucked (out). If the jitterbug caused this then it is much more likely that it had removed noise overlaid on the digital signal and what you were hearing was just the more accurate music. Your "slower, veiled, lifeless sound" is more likely to be the correct sound without noise. If the digital signal integrity is properly compromised then you will hear pops and crackles and not slightly different nuances to the music.

 

[Joe-Siow]

It has been a very interesting discussion on the various inputs and also USB enhancement devices

I took the afternoon to experiment with the Uptone ISO Regen in and out of my setup to see if I can hear any noticeable difference

With the SOTM SMS-200 connecting directly to Qutest via USB, I still enjoy my music; details is still forthcoming without sounding clinical, imaging is still pinpoint and overall sound quality is still very good.
With the ISO Regen plugged before the Qutest and playing the same few tracks, the music flowed with more ease and breathe better, sounding more natural with more air and space.

I've had the ISO Regen in my setup for the past 9 months and it is a keeper IMO. YMMV of course.

 

[Joe-Siow]

Also, a subject that has the horse almost flogged to death; PSU.

My upgraded Uptone LPS-1.2 replacement for a dead LPS-1 arrived yesterday.
Just out of curiosity, I plugged it to the Qutest today.

Results: My my my. I might have to get another LPS-1.2 or even consider the JS-2 for the SMS-200 and ISO Regen, but let's not get ahead of myself first.

 

[TomWoB]

File transfer via USB and audio stream via USB are not the same thing. Here is some info about it:
https://darko.audio/2016/05/gordon-rankin-on-why-usb-audio-quality-varies/

Yes, I know these points, summarized:

• USB transmission is never perfect
• in case of USB file transmission: the USB protocol allows to resend the failed packages, until file is 100% bit-perfect as the original
• in case of audio transmission: yes, we can have a problem, because in case of a "continuous stream" we maybe don't have enough time to resend failed packages

Fine that's clear ... but why do we handle USB Audio still with a "continuous stream" ???
He .. we have 2019, we have already USB 3.1!

Here is my proposal for a "new USB Audio Protocol"

• if we want to hear "a track", the streamer (which is not longer a "streamer") sends THE COMPLETE TRACK AT ONCE to the DAC (like a 100 % bit-perfect file transmission)
  
• let's put 1 GB of RAM into the DAC that it can store the whole track in a buffer
• USB 3.1 allows to transmit the "maybe few 100 MB of a classical track" in less then 1 second ... (USB 3.0 will be a little bit slower, so what)
• USB 3.1 allows to transmit the track bit-perfect, because failed packages will be resend (like storing a file bit-perfect on an USB-Stick)
• all our laptops run with SPS, but storing files bit-perfect on an USB-Stick is absolute no issue
• so "streamers" with SPS, which send complete tracks, don't have a power supply problem
  
• btw: the same will also work with Ethernet LAN connections

So again ... why we still "use continuous streams for USB audio" (or in general on digital side) ?

• radio stations need streams, that's clear but
• for all our music stored in files, I don't see longer any need for a continuos stream
• let's send the complete file/track "at once" to the DAC (1GB RAM in the DAC should be cheaper than a 1000$ USB cable)
  
• it will buffer the whole track
• a lot of problems are gone (transmission problems, clocks, jitter, ...)

Best regards
Tom

 

[nephilim32]

Yes, I know these points, summarized:

• USB transmission is never perfect
• in case of USB file transmission: the USB protocol allows to resend the failed packages, until file is 100% bit-perfect as the original
• in case of audio transmission: yes, we can have a problem, because in case of a "continuous stream" we maybe don't have enough time to resend the failed packages

Fine that's clear ... but why do we handle USB Audio still with a "continuous stream" ???
He .. we have 2019, we have already USB 3.1!

Here is my proposal for a "new USB Audio Protocol"

• if we want to hear "a track", the streamer (which is not longer a "streamer") sends THE COMPLETE TRACK AT ONCE to the DAC (like a 100 % bit-perfect file transmission)
  
• let's put 1 GB of RAM into the DAC that it can store the whole track in a buffer
• USB 3.1 allows to transmit the "maybe few 100 MB of a classical track" in less then 1 second ... (USB 3.0 will be a little bit slower, so what)
• USB 3.1 allows to transmit the track bit-perfect, because failed packages will be resend (like storing a file bit-perfect on an USB-Stick)
• all our laptops run with SPS, but storing files bit-perfect on an USB-Stick is absolute no issue
• so "streamers" with SPS, which send complete tracks, are not a problem
  
• btw: the same will also work with Ethernet LAN connections

So again ... why "we use still use continuous streams for USB audio" (or in general on digital side) ?

• radio stations need streams, that's clear but
• for all our music stored in files, I don't see longer any need for a continuos stream
• let's send the complete file/track "at once" to the DAC (1GB RAM in the DAC should be cheaper than a 1000$ USB cable)
  
• it will buffer the whole track
• a lot of problems are gone (transmission problems, jitter, ...)

Best regards
Tom

This post is interesting and caught my eye in the world of usb/computer based audio . it makes me think of what my Cyrus CD i implores technology wise . The Cyrus engineering way uses an information or data reading system called servos technology .Servos tech gathers up all the data from a CD all at once to avoid sound anomalies like timing issues and to avoid using the dreaded ' error correction' like found in many conventional CD players and Apple I tunes import disc settings .
All I want to say is that with a "gathering of data all at once" philosophy really does lead to much better audio, especially with the timing of your music .
Makes a huge difference so I think your post here, Tom is great!

I appreciate and love all kinds of audio set ups, but I am simply a purist.
I'm a CD guy and I use my Qutest with my CD i to get the best results for me of course.