How good of a DAC is the Logitech Transporter


I have a Squeeze Box 3 digital out to a Tri-Vista 21. I am considering upgrading to a transporter main reason to get HI-RES native 96/24 FLAC download music which the transporter supports.
My question is the transporter a great sounding stand alone DAC and will I hear a difference between 48/24 through my present up sampled Tri-Vista 21 vs. 96/24 native supported transporter.
Thank you in advance for your feedback.
audiogalore

Showing 7 responses by aplhifi

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
(2) i can always purchase another new transport/streamer to go with the Transporter's built-in DAC (via digital inputs?) when higher than 24/96 is supported

Yes, but the wireless transmission in the Transporter is asynchronous so the master clock jitter the AKM DAC see is very low, unlike the S/PDIF input where the master clock comes from the digital receiver and can be 100 times more, at least.

Since I believe AKM DACs are really special (and I use them in all of my products), there is no doubt that the AK4396 DAC in the Transporter is nice (although inferior to the latest 32 bit AKM top-line DACs, IMHO!). Of course, it is all implementation, so "everything matters". And we can't really blame AKM for introducing much better 32 bit DAC solutions after the Transporter was released.

Hope this helps!

Best,
Alex Peychev
www.aplhifi.com
Hi Raymond,

Yes, that is correct; the clock jitter coming from the S/PDIF receiver (all digital inputs) is very high compared to the low jitter clocks used for the wireless.

IMO, this is the major reason why many prefer audio stream from their computer/server against a CD transport. Of course, IMO again, a CD transport can sound better than computer audio, but that is another story. :-)

Best,
Alex Peychev
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
Raymond, I am evaluating Transporter and Hiface as "digital transports" with my DAC using S/PDIF connection (I am not interested in the Transporter DAC/Analog section). So, I wouldn't say that Hiface is just a convenience and, unlike Transporter, it is 192KHz/24bit capable.

Best,
Alex Peychev
Raymond, the Transporter is limited to 96K so adding Hiface will not help. Even when used as a digital source to an external DAC, the Transporter still can't do more than 96K. Of course, the newer Slim Servers make possible the playback of audio files with higher resolution, but these are being down-sampled to the 96K limit.

What you can do is experiment with a Hiface plugged to your laptop, feeding the Transporter digital input. In this case you will have 192/24 capability. But as I previously mentioned, the clock quality will be greatly decreased because it will come from the digital input receiver that uses PLL for the clock recovery. In other words, you will not be able to hear the full capabilities of the Hiface.

I will let you know about my findings once I complete the evaluation but, so far, at equal playing fields, I strongly prefer the Hiface. In fact, I like it so much that I will be using M2Tech USB interfaces in my digital products.

Best,
Alex Peychev
www.aplhifi.com
I am sorry for the confusion, Raymond!

When used as a network player (wi-fi or LAN), the Transporter is limited to 96/24. This is due the processor they are using, I would guess.

When used as a DAC with its digital inputs, the Transporter can do 192/24 because the DIR (Digital Interface Receiver) and the DAC chips (both made by AKM), are capable of this resolution.

Best,
Alex Peychev
www.aplhifi.com