USB to I2S: M2Tech vs XMOS vs Open-source Qnktc

[audiodesign]

I am testing these 3 USB-I2S interfaces:

- M2Tech module by AckoDAC (https://sites.google.com/site/ackodac/home)

- XMOS by Lucian (http://www.diyaudio.com/forums/digital-source/188902-xmos-based-asynchronous-usb-i2s-interface.html)

- Open Source by Qnktc (Q N K T C)

All are asynchronous USB Audio device using two quartz precision oscillators to clock source for output data stream with a very low jitter.

I have tested these interfaces connected at the same DAC chip and there are many differences in the listen test.

 

[audiodesign]

Here an example of the test environment

http://www.audiodesignguide.com/HiResolution/WM8740sch.jpg

Now I have left the WM8740 because I have found a bad sound with some new production chips.

The my choice now is the AD1955 with active I/V and Lundahl transformers.

I am testing some configurations to use the AD1955 with passive I/V.

 

[RayCtech]

Here an example of the test environment

http://www.audiodesignguide.com/HiResolution/WM8740sch.jpg

Now I have left the WM8740 because I have found a bad sound with some new production chips.

The my choice now is the AD1955 with active I/V and Lundahl transformers.

I am testing some configurations to use the AD1955 with passive I/V.

When will you start the testing ?
I have M2Tech USB -> I2S, QNKTC / Audio Widget USB -> I2S, exaU2I USB -> I2S and other USB -> I2S devices...
And have done my own testing so your results would be interesting 🙂

 

[audiodesign]

I hope this weekend.

Two my friends with a lot of experience on music reproduction and live recordings will be present at the test.

Obviously I will indicate only the best to have no problems.

 

[RayCtech]

I hope this weekend.

Two my friends with a lot of experience on music reproduction and live recordings will be present at the test.

Obviously I will indicate only the best to have no problems.

I forgot to mention the USB -> I2S device I am currently using so the units I am using that are worth mentioning are: Light Harmonic Titan USB -> I2S, M2Tech USB -> I2S, QNKTC / Audio Widget USB -> I2S and exaU2I USB -> I2S...

 

[audiodesign]

Do you have 4 interfaces ?

 

[RayCtech]

Do you have 4 interfaces ?

Actually more than that, but I normally uses them one at a time...
I have IR remote controlled input switching so I can switch between I2S inputs and also SPDIF inputs...
When comparing units I have two identical PC / Mac systems with the same music and starts a playlist on both...
Then I can switch between I2S inputs and compare units 🙂

 

[audiodesign]

Which is the best for you ?

 

[RayCtech]

Which is the best for you ?

When your test results are posted - then I can comment my private opinions as I expect my results will be different from yours, and I do not have any XMOS based devices so I do not have the same reference platform as you...

 

[audiodesign]

The AD1955 DAC have current sink outputs instead of current source outputs so I am testing some configurations suggested in this document.

http://www.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=slaa399&fileType=pdf

 

[hochopeper]

When your test results are posted - then I can comment my private opinions as I expect my results will be different from yours, and I do not have any XMOS based devices so I do not have the same reference platform as you...

A technicality, but I though the Titan was a xmos chip, though certainly a different xmos chip to the WaveIO board!

I'm quite interested to see outcome in this thread.

 

[analog_sa]

I'll volunteer a guess for the winner: Exa, but heavily modded 🙂

 

[RayCtech]

I'll volunteer a guess for the winner: Exa, but heavily modded 🙂

I know that there is one exaU2I with my JFET regulators in Sofia 😀
With a acko ES9012 DAC etc. etc..

 

[wlowes]

Great idea!

I am most interested in hearing your results. My bets are on WaveIO. I use it with external power supply but with the uBMC connectors.

Have you tried comparing the uBMC vs the isolated I2S output? I have read that isolation chip adds some jitter.

Also, can you share how your PC is set up and what player?

 

[audiodesign]

I need to specify that the Twistedpearaudio.DAC with Sabre ESS ES9018 cannot be considered a good DAC module for this test because it does not use the master clock of the I2S bus generated by the USB-I2S interface.
The Twistedpearaudio.DAC reclock and resample with another oscillator so the sonic performances with Twistedpearaudio DAC could be completely different, worse or better, but in any case the accuracy of the modules USB-I2S is not used.

 

[audiodesign]

I am a Windows user so I normally use Foobar2000 with Convolver module for the DRC but these tests will be performed on a my friend house with MAC OS X, Fidelia by Audiophile Engineering player (Audiofile Engineering - Fidelia) and LA COnvolver for the DRC.
The loudspeakers used will be ESL 57 or vintage Spendor driven by my 813/GM70 SE amplifier.

DRC
Digital Room Correction

813/GM70 SE Amp.
813 / GM70 amplifier with Bartolucci transformers

 

[RayCtech]

As I use a bitperfect approach I can listen to the differences of the USB -> I2S units..

The use of Fidelia and DRC are a completely different kind of game and your "test" results would be incompatible with mine.

But maybe your friend could play using the BitPerfect app (iTunes) and check the fidelity in a close to bitperfect setting.

 

[wlowes]

Even though we all have different use cases, this promises to be a very interesting comparison. It would be great if you could to do one round of listening with as little processing of the source signal as possible.

 

[audiodesign]

In the first test XMOS is the best and the differences are very big.

813/GM70 SE Amp. + Quad ESL63

 

[RayCtech]

In the first test XMOS is the best and the differences are very big.

813/GM70 SE Amp. + Quad ESL63

I had already ordered a WaveIO for evaluation so this was good news