Ultimate USB/SPDIF converters shootout

[chessman]

Adam, thank you for an outstanding review. You have provided many useful reference points, valuable information and real insights.

[Stereo-head]

Originally Posted by Glisse

Forgot to add that Berkeley is not easy to buy in the EU because it is not RoHS compliant. Nor will Berkeley make it so, as they believe it affects the SQ.

It can be bought by contacting the Swiss distributor.

Good to know Glisse. Where are they made?

[bakerman]

Originally Posted by Stereohead

Good to know Glisse. Where are they made?

Berkeley, California.

[lostinla]

I have tried a few converters too and now use an AP2 with PP and I'm very happy with it. I've tried it on some high end DACs and it has bettered the USB input - a little smoother, quieter etc.

Very keen to try the Alpha USB converter after reading this. Great thread

[Stereo-head]

Originally Posted by bakerman

Berkeley, California.

Thanks Doug. Made in USA, can't be sold in the USA. Bold move.

[Glisse]

Originally Posted by Stereohead

One thing I'd like to add/clarify to some readers is that USB/SPDIF converters are called, well, USB/SPDIF converter. I prefer the name reclockers, or master clocks. Yes, they do convert the signal to SPDIF from USB, but I don't see that as it's main function. The most important job it does is reclocking the signal and outputting an ultra low jitter signal that results in a significant audible improvement in sound quality. With exception to some really top dog DACs, the clocks on these converters easily beat the one's on the DAC.

Good point, although it should also be noted that the SPDIF stage is imperfect, and will generate a degree of jitter itself. The DAC must still have an inherently accurate clock to take advantage of the better converter in front of it.

It was interesting that Berkeley built the Alpha USB as a standalone piece, rather than integrating into the DAC 2. Whilst they acknowledged that an I2S feed direct to the DAC (chip) is theoretically better than an SPDIF conversion stage, they felt the isolation of the USB stream was even more important.

[JemHadar]

Adam, thank you for this excellent post.

[Glisse]

Originally Posted by Stereohead

Thanks Doug. Made in USA, can't be sold in the USA. Bold move.

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.

[-E-]

Thanks.

Everybody should be reading this.

[Stereo-head]

Originally Posted by Glisse

Good point, although it should also be noted that the SPDIF stage is imperfect, and will generate a degree of jitter itself. The DAC must still have an inherently accurate clock to take advantage of the better converter in front of it.

It was interesting that Berkeley built the Alpha USB as a standalone piece, rather than integrating into the DAC 2. Whilst they acknowledged that an I2S feed direct to the DAC (chip) is theoretically better than an SPDIF conversion stage, they felt the isolation of the USB stream was even more important.

Yes it is interesting. Although integrating the ALPHA USB into the DAC 2 would push the price of the unit to considerable levels.