Unitiserve vs Mac Mini

       


Thanks Jan.

YanC, picking up on your earlier posts of why digital is variable in analogue quality. Well here goes, and the more you research it the more amazed digital sounds as good as it does... If you search some of my earlier posts last year, you will see more descriptions of why this is so and why USB can be bad for RFI creation.

sPDIF and USB used streamed data. This data contains protocol data as well as payload data. Therefore it is not a case of simply converting a 'bit stream' to a stream of sample words, the serial stream needs decoding and the payload unpacking. It is this payload that is then carefully clocked to the DSP/DAC.
Now if you delve into the world of DSP, you see that 'bit perfect' really ihas lonly partial  significance to sample data at the point of conversion or encoding. It is eactually the TIMING of the samples are as just as important as to what the samples are. Therefore the clocking of the earlier recovered payload into the DSP/DAC is of paramount importance.
Now in the real world that earlier payload recovering and any RF interference coupled into the Powerlines cam cause  perturbations in this critical DAC/DSP clock.(the better the DAC, thevsmaller these become).This has the effect of adding distortion frequencies into the stream rate of sampled data. The net effect is when thiese samples are converted into a continuous analogue signal by the DAC's transfer function, there will be distortion to the analogue waveform,

In other words you could have a 'bit perfect' serial stream and still have a distorted analogue waveform because of disturbances in the clock.
Also this clock is SEPERATE from the transport clock used for USB or SPDIF. SPDIF transport jitter has nothing to do with sample jitter, unless through implementation decoding the jitter cause perturbations in the master DAC sample clock.

In the world of analogue to digital and digital to analogue  conversion there are many variables that can 'pollute and colour the sound', and the process itself can never be exact. All digital does is allows a method of retaining integrity of the digital signal through transporting it. The penalty however is at the conversion ends of the process. There is no such thing as a free lunch :-)

Simon

Guido... Again you say the new V-Link (I assume you mean the 192 version) has no galvanic isolation but this is incorrect according to Musical Fidelity's website.

Eloise

Galvanic isolation can be accomplished by using a transformer...

       

Okay I've read the HiFi News review and they do question if transformer coupled counts as isolated (though I believe it's a term generally used) so I see your point.

Eloise

I struggle to hear any difference between 192khz and 96khz too.