Device Type: USB Wireless Upsampling DAC
Input: USB (transmitter), Wireless 802.11/g (receiver)
Output: (1) pair RCA, (1) Toslink
Dimensions: 4" diameter x 1 1/4" h (tx), 4" x 4" x 1 1/4" h (rx)
Weight: about 2 lbs combined
Availability: Online through manufacturer's website
Price: $449.99
Website: www.playgo.us

Green Means Go
The playGo USB is to my way of seeing a fine industrial design. It’s clearly not your typical black stamped-metal box with a slightly fancier façade kinda deal. Rather these things, the transmitter and receiver, have character. Made from DuPont’s Corian of kitchen counter fame, there’s one that’s round (the transmitter) and another that’s square with rounded edges (the receiver). Both sandwich an opening so you can see their LCDs glow to signify various operating modes; solid red (power is on but the devices do not see each other), solid green (power is on the devices see each other), pulsing green (music is playing) and pulsing red, green and blue (power is on and the units are in connecting mode). While you can defeat the LCD display, why would you want to especially this time of year. I actually like their cool warm glow and the amount of light they emit is not too much for me. Om.

I confirmed with a USB Prober Utility that the playGo transmitter is limited to 16 bit/48 kHz, which is exactly what Audirvana and Apple’s Audio MIDI programs told me since this was the highest bit/sample rate available with the playGo selected. The odd part was I had connected the Musical Fidelity M1 DAC to the playGo receiver via Toslink and the DAC1 displays the incoming sample rate right on its faceplate and it said 96kHz! What the…? Well, it turns out the playGo transmits at a maximum rate of 16 bit/48 kHz (and let’s make sure we understand that fact since I’ve seen other claims floating around the blogosphere suggesting otherwise). The playGo receiver receives that 16/48 signal from the transmitter and before handing it off to the internal DAC or Toslink output, it sends it through a Burr-Brown SRC4192 asynchronous sample rate converter which upsamples everything to 24 bit/96 kHz. Aha!

You can change this default setting to upsample everything to 24 bit/ 192 kHz but this option is limited to the DAC/RCA outputs. It is not available via Toslink. So what's up with that? I asked Ekin Binal the President of BICOM, Inc. makers of the playGo DAC, "What's up with that?". Ekin responded:

The playGo tx uses a PCM2707 from TI which is limited to 32, 44.1, and 48kHz - anything outside of those native sampling rates is downsampled/upsampled by the USB Audio Class driver in Windows or OSX. So you are correct that 48kHz will be the max native rate you will see. The playGo receiver has an asynchronous sample rate converter stage before the DAC and digital output that automatically upconverts every incoming audio to 96/24, optionally 192/24 for the DAC (most Toslink inputs don't support 192). The reason we did this was because in all our lab tests and beta sites most of our targeted customers were listening to 44.1kHz, this combined with the ASRC at 96kHz both measured with great results but more importantly pleased the test base the most from an audio quality perspective. The PCM2707 was the most cost effective option at the time of original development (March 2010).

Texas Instruments worked with BICOM on this ASRC implementation and they offered some additional information:

TI is pleased to have been part of the PlayGo product family.

There are two key benefits to using an ASRC along with a DAC output stage.

Typically, in DAC's, there are two sources of high frequency out of band noise. The Digital Upsampling Interpolator typically has a stop band attenuation characteristic, above the audio sampling frequency (anywhere between -60dB and -120dB). Additionally, the Delta Sigma Modulator (DSM) of the DAC also has a role in the out of band noise of the DAC.

Firstly, an asynchronous sample rate converter, when used with a DAC assists the DAC's internal upsampling interpolation filter by shifting the data up to 192kHz, without adding out of band noise below 192kHz. This removes the impact of the digital upsampling interpolator on frequencies below 96kHz.

This leaves the main influence on out of band noise as the DSM of the DAC.

Secondly, an ASRC acts as a reclocking system, by allowing the DAC side to run in a master mode, or to run from a constant crystal based clock source, rather than an audio clock regenerated from low frequency. This is especially present in USB systems, where the data rate may be quite jittery, as the master clock, bit clock and lrck is regenerated from the USB clock rate.

Perhaps a little history is in order. BICOM was founded in 1988 by Dr. Mehmet Binal, Ekin's father and their "products and designs focused on voice processing platforms for the telecommunications industry". Today BICOM has moved its focus to among other things IP-based audio. It's worth a peak at playGo's sister company’s website zoet whose focus is multi-channel multi-room audio products. They've also developed some digitally powered IP-enabled speakers in conjunction with speaker manufacturer Thiel.

I also asked Ekin about the wireless protocol used in the playGo since this information is not listed anywhere that I could find. Here's his answer:

We use a Radio chip that is used for 802.11b/g but the algorithm we use to transmit our audio in real-time is not standard wifi or 802.11g.

I have to assume BICOM is leveraging their IT/Telecom background with this implementation and further that algorithm is of the - I can tell you but then I’d have to kill you - variety. According to Ekin you can "comfortably" connect up to 4 receivers to each transmitter but seeing as I had only one of the square units I did not try a multi-room setup. Since we're talking about a single transmitter that is controlled by whatever music player you're using, I'd have to conclude that every receiver will play the same music so we're not talking about having the capability of different zones playing different music like a Sonos system.

In terms of playing with the playGo USB, connection was a breeze: no drivers required just connect the included USB to mini USB cable from computer to receiver, and I tried both the RCA outputs to my Leben CS-300XS integrated amp as well as Toslink out using the included cable to the Musical Fidelity M1 DAC. The receiver also needs to be plugged in via its wall wart power supply and you have to point your system and where applicable your music player of choice to the playGo. Within a minute or so after doing all that the units were glowing a steady green (power is on and the devices see each other). Within a minute or so after that they were pulsing green in sync (sexy). It also meant music was playing.

The receiver also has a few basic touch-sensitive controls on top that glow yellow when you touch ‘em (very cool in Corian, isn't it) including Play, Next, Back, On/Off and if you press the push button and the standby button simultaneously you can change the default settings to disable the lights and volume control as well as set the RCA outputs to upsample to 24/196. I tried all of the playback controls and they worked with all of the media players I used (Audirvana, iTunes/Pure Music, foobar200). However for the majority of the time I did not use these preferring my computer’s controls or the remote iTunes app for the iPhone/iPad. I also defeated the playGo's volume control preferring its fixed output mode.

What's Up With That?
In my mind I could imagine all kinds of reasons why the playGo would not sound good. All that rollercoastering up and/or down and up sampling, wireless transmission, switched mode power supply, Corian, and lights pulsing but I'll be damned if I didn't immediately think, wow that's not bad at all. As a matter of fact, that's good. Even straight out using the playGo's internal DAC, music was lively, bright and nicely textured. Fun was a word that came to mind most often. The old sins of omission in play since there were things the playGo was not doing like providing a clear delineation of parts for more complex music and all of the various colors and fine-hued differences of instrumental voices were not present. Yet music was still fun to listen to.

I streamed from LAST.FM (still getting my 1 month's money's worth but after that I'll move on), streamed from MOG (now that's more like it!), played tracks from my iMac via Audirvana's free player, from iTunes/Pure Music via my MacBook Pro and from foobar2000 via my PC. I also took the playGo receiver while connected to the MacBook Pro for the same guided tour of our home that the NAD Wireless USB DAC went on and I got similar results in terms of range minus about 10ft. or roughly 50 feet total distance from the receiver before they lost sync (and pulsed red indicating sad). While within range I did not experience any dropouts over the course of a couple of weeks of listening. I will state again that we live in a fairly un-congested area so those living closer together may experience more wireless interference.

When adding an outboard DAC via Toslink to the playGo, the Musical Fidelity M1 DAC, there were clear and easily noticeable improvements namely reviving the aforementioned tonal color spectrum and opening up the soundstage with both more space and finer delineation of space-based queues. Better in every way. One interesting thing to note is the M1 DAC automatically upsamples all incoming data to 24 bit/192 kHz so in effect I was listening to a doubly upsampled signal! The natives were getting restless. But even with all this processing, I have to say the music persevered and even more—it was still fun to listen to.

I should mention the related elephants in the room; the playGo's $449.99 price tag and the Logitech Squeezebox Touch which retails for $274.99 (but I've seen it as low as $228 on Amazon). The Squeezebox Touch offers wireless connectivity with up to 24 bit/ 96 kHz playback, a touchscreen display, the ability to direct-connect an external USB hard drive, very user-friendly server software, a remote app, an internal DAC and Toslink output to name but a few features. It's certainly also worth noting that the playGo USB is designed, manufactured, and hand assembled in the USA according to BICOM whereas the Squeezebox Touch is made in China (it says so right on its bottom like a tattoo).

I went back and forth between the Squeezebox playing files from a direct-connected USB hard drive as well as a wireless connection from my MacBook Pro and the playGo wirelessly connected to my iMac. Using the headphone output on the Leben CS-300XS with Audio Technica ATH-W1000 headphones I noted the differences were slight but I'd give the overall nod to the playGo for a more resolute presentation. It was close mind you, but not too close to call.

Summing The Difference
It would be difficult to whole-heartedly recommend the playGo without reservation even though I like the way it works, looks and sounds without at least giving a nod to the Squeezebox Touch for its ability to handle higher resolutions (up to 24/96 as opposed to the playGo’s 16/48), offering a greater feature set and a lower price coupled with nearly comparable musical performance. I do believe there may be some people out there who do not want all of the additional features the Squeezebox Touch has to offer yet still want and need a good-sounding wireless solution. For those people who do not have any interest in playing back 24 bit recordings in their native format (and if you have them you should) the playGo is very easy to recommend.

It's also worth noting that BICOM has the playGo USB HD coming this spring, which will support high resolution playback. Details are not available yet but for those interested in this package, stay tuned.