Ultimate USB/SPDIF converters shootout

[Stereo-head]

Originally Posted by Glisse

It is in the EU, not the US, where sale is restricted. The EU have restricted sales of products containing lead, amongst other things. Which means products must use lead-free solder to comply. Lead-free solder doesn't flow as well, so it is a compromise.

I believe Berkeley have their products made for them - they are basically a 3 man design team. And very talented designers at that with a long history.

Ahh thanks for the clarification Glisse, (EU is our spanish translation for United States) my bad.

[o0OBillO0o]

..and I aspire to deliver such great info to the masses! Well done! **STICKY PLEASE**

[jason]

This is an amazing and valuable review. I've been thinking about a USB/SPDIF converter for a while. This may really push me over the edge.

Thank you!

[Elberoth]

Originally Posted by Stereohead

I prefer the name reclockers, or master clocks.

Not sure if we can call them that way. To me, reclockers are devices that 'reclock' the signal, say SPDIF to SPDIF - prime examples would be Empirical Audio Pace Car Reclocker, Genesis Digital Lens etc.

We call them converters, because they convert USB signal (which is very different to SPDIF signal) to SPDIF one. Yes, they have their own clocks (in case of Berkeley - very sophisticated ones) but so does any CD transport.

Same for Master Clocks.

[Elberoth]

Originally Posted by Glisse

The DAC must still have an inherently accurate clock to take advantage of the better converter in front of it.

Yes and no. It will all depend on the PLL design and PLL cut-off frequency.

Most of the DACs, especially the cheap ones, have rather high PLL cut-off point, which means that for the most of the time they rely on an external clock, not the local oscillator. In such a case, providing a low jitter transport can bring huge improvements in sound quality.

DACs that should benefit least from low jitter transport, are the ones with low cut-off point in PLL. Those are mostly expensive DACs, like the dCS which has a cut-off frequency of 100Hz.

The easy way of telling if the cut-off point in PLL is low or high, is to observe how long does it take the DAC to lock to the signal. If the lock is instantaneous, then the cut-off point is high and the DAC will most likely greatly benefit from the low jitter source.

If it takes the DAC several seconds to lock to the signal, then the cut-off point is low and the DAC should be less sensitive to the incoming signal jitter (which is good or bad - depending how you look at this; good if you are feeding the DAC with a jittery signal; bad if you are feeding the DAC with signal that has less jitter than the onboard clock in your DAC, as the improvement may be small).

Here is a good reading on PLLs:
http://www.grimmaudio.com/whitepaper...k%20basics.pdf

[Elberoth]

Originally Posted by VT Skier

Hi Adam,

I don't own the Soulution CD player I used during the demo against the Berkeley. I'm also not familiar with the Clock Link feature.

Jon

The Soulution 590 USB/SPDIF converter has a clock output (on BNC) which can be used to send clock signal to a CDP equipped with a clock input (say Soulution own 745 CDP or a dCS DAC or player).

The clock link is used to get rid of SPDIF interface jitter.

[enit]

Pleasurable read! Thanks!

Sent from my iPhone using A.Aficionado

[dcc]

Once again, you left out one of the best sounding converter from your survey, the AR-T's Legato II.



Yes, it only does 44.1K, but I'll bet that the digital music collection of most people reading this thread is over 90% redbook recordings.

[Pider]

What a great and valuable write-up! Thanks so much.

[jdandy]

Adam.......An excellent review of USB/SPDIF converters with some fine photos. It is threads like this one that add great value to Audio Aficionado. Well done.