How good of a DAC is the Logitech Transporter

Sure, wireless or wired with LAN cable, the clock jitter remains very low. Of course, you can experiment and see if you hear a difference between the two.

Best,
Alex Peychev

i doubt i would be able to hear the difference though, i mean between wireless and wired.

i know the Transporter doesn't have USB, but how would USB compare to network or S/PDIF performance wise? as high end as the Transporter is, it's a shame Logitech/Slim Devices forgot to include something as simple as an USB, which even a dirt cheap transport/streamer would have one these days.

I believe a USB solution would still ultimately involve an S/PDIF conversion operation - and thus there would be no reason to use USB with a Transporter. A main feature of these SlimDevices units is to avoid any such S/PDIF conversions - the network connection avoids S/PDIF and gives an optimum connection medium.

Also, regarding whether there are "better" AKM dac chips available, keep in mind that Sean Adams (designer of the Transporter) implemented the chosen AKM dac chip in a very optimized way. Here's a quote-snip from him:

Sean Adams: "However, in the case of Transporter there is a very large improvement over the manufacturer's specs because we are using the chip in a far more advanced design than AKM's evaluation board. For the THD+N figures this is especially due to the jung regs and the selection of certain passives in the amps/filters. The clocks are very important too, but this isn't meaningfully reflected in THD+N tests."

I've been evaluating the Hiface USB to S/PDIF from M2Tech. With my asynchronous DAC, the Hiface considerably outperforms my Transporter (both upgraded or stock). The Hiface was connected to my Sony VGN-SZxxx Sony Laptop streaming wirelessly audio files from the same server used by the Transporter. Player is Foobar with KS plug-in.

As for the DAC/Analog stage of the Transporter, it is the same as in the AK4396 datasheet recommended circuit for balanced + single ended output (page 35, fig 17). As you can see, there are coupling capacitors at the DAC outputs and NJM5534D Op Amps.

"However, in the case of Transporter there is a very large improvement over the manufacturer's specs because we are using the chip in a far more advanced design than AKM's evaluation board."

I think I'll point AKMs attention to this statement. :-)

Best,

Alex Peychev
www.aplhifi.com

Alex, your Hiface/DAC outperforms the Transporter, maybe because your DAC is simply better but not because Hiface USB-S/PDIF is better than network?

Fiface is more a convenience device instead of an enhancement, right? if i stream wirelessly (or via ethernet) from my laptop to the Transporter, then i don't think using an USB-S/PDIF would improve over network, right?