The Logitech/Slim Devices Transporter is the Grand Pooh-Bah of the Squeezebox line. Slim Devices claims it’s “designed to appeal to the most discerning audiophiles and music lovers…as a no-compromise attitude to component selection and electronic design.”
One major advantage the Transporter has over other Squeezeboxes as well as Apple TV and Sonos is that it can handle any digital signal up to and including 96kHz/24-bit. The Transporter is the first true high-definition digital music server available for under $2000. If you want to play high-definition digital music anywhere in your home, the Transporter is the box for you.
Where will a Transporter transport you? Like other Squeezebox units it gives you access to your own music library through Logitech’s SqueezeCenter software. The Transporter can also connect with Logitech’s SqueezeNetwork via an Internet connection. This opens up a plethora of music services including Rhapsody, Pandora, Last FM, Slacker, Deezer, Live Music Archive, and, of course, all of Internet Radio. You can also buy and download CDs from Amazon’s music store through your personal SqueezeNetwork account.
The Technical Tour
The Transporter certainly has the high-end look. With its pro-style mini-rack handles, big and bright simulated VU meters that go to +3 (the audiophile equivalent of going to 11 à la Spinal Tap), the choice of a silver or black front faceplate, and a centrally located big black knob, the Transporter has all the visual presence of a real top-shelf audio component. But as we all know, looks aren’t everything. It’s what’s inside that counts.
The Transporter utilizes three separate power supplies based on a Walter Jung design—one for the positive analog, one for the negative analog, and one for the digital circuitry. Although the Transporter uses an AKM AK4396 multi-bit Sigma-Delta reference DAC, the Transporter’s carefully configured parts-integration techniques results in 8dB quieter measurements than a stock AKM. Special attention was put into the design of the digital circuitry so it can deliver maximum clock-signal integrity. To handle different clock rates the Transporter employs multiple crystal clocks so it doesn’t resort to re-sampling or PLL devices. The Transporter’s digital circuit also re-clocks all incoming signals to reduce jitter.
Because the Transporter is more than just a networked music player it has inputs for “legacy” digital sources. It has one TosLink, one coaxial S/PDIF, one BNC S/PDIF, and one balanced AES/EBU as well as a digital word-clock input. The only thing it lacks is a USB input.
For outputs the Transporter sports one pair of unbalanced single-ended analog RCA outputs, one pair of balanced XLR analog connections, and matching digital outputs for each of its digital inputs. These digital outputs are not “pass-through” connectors because they are only active if you are using the Transporter as a source. So the Transporter is not a digital switcher, but a DAC that accepts multiple sources. The rear panel also has two WiFi antenna connectors, an Ethernet connector, a RS232 serial connector, and a standard IEC AC jack.
The Transporter’s front panel features a big bright vacuum fluorescent display (VFD) on the right side that can be configured to show VU meters, EQ volume bars, song title information, or nothing at all. The left half of the front panel has another VFD that keeps track of what’s playing when you’re not navigating through the Transporter’s many menus. In the center of the Transporter’s front panel is a large circular knob. In addition to serving as a volume control, it’s also a navigation knob that moves you from one menu choice to another. If you use the remote to operate the Transporter, you’ll never touch the front panel except to clean off accumulated dust.
The remote that comes with the Transporter is almost the same remote that you get with the basic model Squeezebox. The only difference is that the Transporter’s remote lights up when you push any of its buttons. However it doesn’t supply any feedback about whether your keypunch selection has had the desired effect. You have to look at the Transporter’s front-panel display to ascertain the remote’s efficacy. For the added cost of $299 you can buy the Logitech Duet’s remote and use it with the Transporter. The Duet remote does all the things a good remote control should do—lights up, has a color display, and, most importantly, tells you where you are in the Transporter’s multi-tiered menu system. Frankly I’m disappointed that the Transporter lacks the far superior Duet remote, but since the Transporter came to market over a year before the Duet, it’s not surprising that it doesn’t. Fortunately many Logitech dealers will sell you a Transporter bundled with the Duet remote if you wish.
With four digital inputs a Transporter should be able to support and control a fairly complete digital-only music system. I appreciate that it includes a pro-standard AES/EBU digital input. But some prospective users may not be as pleased by the Transporter’s analog output choices.
With only two pair of analog outputs, both tethered to a digital domain volume control, anyone in need of a fixed-level analog output has limited options. Sure, he can set the Transporter’s volume level at 0dB to get a fixed line-level out at 2.0 volts unbalanced or 3.0 volts balanced, but this effectively bypasses the Transporter’s volume adjustments. While many users who incorporate a Transporter into an existing multichannel system set up the Transporter in this manner, if your inclination is toward a more minimalist system with the Transporter as your sole preamp you may have to do without a fixed line-level analog output.
A possibly more problematic shortcoming is that while the Transporter has three jumper switches located inside its chassis to attenuate the analog output level by 10, 20, or 30dB, this attenuator only works on the unbalanced RCA outputs, not the balanced XLR connections! Why is this an issue?
To get the best sound out of a digital volume control that truncates bits at lower volume levels (digital volume controls throw away one bit of resolution per 6dB of attenuation—Ed.) you should set up your system so that the volume control is nearly all the way up for critical listening. If you use the unbalanced outputs you can take advantage of the Transporter’s built-in attenuators. But if you want to run balanced interconnects between the Transporter and your power amplifier you’ll need to insert a fixed attenuator. Otherwise the signal level could be excessively high. But what if you need to use that balanced output for a subwoofer? You’re going to have a devil of a time getting the levels between the two outputs to match up precisely. That 30dB difference will require your subwoofer input level to be set so low that it may not track accurately. It’s really a shame that Logitech didn’t see fit to make the internal attenuators for both analog outputs.
Since I wanted to hear how the Transporter sounded at its best, I kept it installed in my desktop system for a good part of the review period. There I mated it with my vintage but completely refurbished Accuphase P-300 power amplifier. The P-300 has variable volume attenuators located on its front panel, so I used the Transporter’s outputs at full level and adjusted listening levels with the Accuphase’s input controls. While this method worked well for me, it doesn’t solve the problem for most prospective users whose power amplifiers lack volume adjustments.
Up, Up, and Away
Setting up the Transporter is easier than setting up a Squeezebox Duet. That’s because the Transporter has a built-in expert system that leads you through the initial installation. To access your music library the Transporter requires a computer or server with Slim Devices’ SqueezeCenter software installed on it. I mated the Transporter with a Music Vault II (reviewed in this issue) pre-loaded with SqueezeCenter, so the Transporter would have its own unique wireless network courtesy of the Music Vault. Once set up the Transporter recognized the Music Vault’s installed music library as well as my Internet radio station favorites.
During the review period the Transporter occasionally dropped the wireless feed from the MusicVault, but in every case after ten seconds it began playing the tracks again with no further issues. I was a bit surprised that the Transporter had any connection issues since my Duet, Apple TV, and Sonos systems are farther from their wireless hubs and have never had any dropouts. One of Logitech’s technical experts suggested that the problem may not have been the wireless network interface, but the SqueezeCenter’s inability to decode Apple Lossless files fast enough. Only Apple Lossless music files had this problem, so I suspect this guess was correct.
Given Logitech’s goal of “no compromise” sonics how does the Transporter actually sound? While certainly competitive with other similarly priced DACs, it’s not about to push any state-of-the-art price-is-no-object $20k DACs off your component shelf.
The Transporter’s analog stage is exceedingly quiet. Even at maximum output, which is how I listened to it most of the time, I detected no hiss or hum even when I pressed my ear close to the speaker driver.
The Transporter’s resolution abilities were excellent, easily matching that of my reference Bel Canto DAC-3. Lateral imaging was especially precise, and depth was certainly on a par with other solid-state DACs I’ve heard recently. However the Transporter’s depth recreation wasn’t quite as fleshed out as that of the tube-output Wavelength Brick USB DAC, whose circuit manages to add three-dimensionality to even the flattest commercial digital recordings.
Although I wouldn’t characterize the Transporter’s overall harmonic balance as harsh or bright, it does have a slightly more mechanical presentation than the Bel Canto DAC-3 on coaxial and TosLink digital sources. The Transporter’s overall rendition was more left-brained and matter-of-fact, emphasizing the details without drawing the listener into the music as completely as the Bel Canto. Both produced excellent bass fundamentals, but at higher output levels the Bel Canto’s more robust active output stage seemed to generate more visceral low bass and dynamic contrasts.
When I compared the Transporter to the Meridian 568.2/518 combo, I noticed the Transporter’s more open and extended top end. Every musical selection had additional air and extra shimmer on flutes, cymbals, and even female vocals. Although the Meridian combo was more musical primarily due to its richer midrange, it was also harmonically warmer and darker and rhythmically slower. Think fudge compared to white chocolate.
On my own 96/24 music files taken from live concert recordings made on a Marantz PMD-671 recorder the Transporter sonically outdistanced every other source in my system by a substantial margin. As Gordon Holt often told me, “Software always trumps hardware.” Being able to play higher-resolution music files catapults the Transporter to the top of the wireless music server (and DAC) heap. Even the Bel Canto DAC-3 sounded inferior when it played the same recordings down-sampled to 44.1kHz. Through the Transporter the higher-resolution versions of the same music had more life, better micro-dynamics, and greater dimensionality.
The Best Way to Get From Here to There
The Transporter strikes me as a versatile product whose flexibility may be its best and worst trait. Since it can be used in more than one way—as a music server, DAC, or stand-alone digital preamp, many users may employ it in a way that prevents it from sounding its best. Although the Transporter has a volume control that allows it to be used as a stand-alone digital preamp, this digital volume control can and will decrease the Transporter’s fidelity if it’s used for more than 10dB of attenuation. Audiophiles who want to extract maximum performance from a Transporter should use it in conjunction with an analog preamp to control its output levels. Although you can use a Transporter as a stand-alone digital preamp, that doesn’t mean you should.
I think the ideal prospective owner of a Transporter would be someone who’s been using a $4k-to-$5k DAC that he purchased five or more years ago, and who is ready for a step up in both fidelity and ergonomic flexibility. Combined with a Music Vault II the Transporter can form an ergonomically elegant portal into the world of digital music. The Transporter can handle all your legacy digital sources, give you access to Internet music and radio, perform as a wireless music server, and let you enjoy higher-definition 96kHz/24-bit music files. It is the only high-end two-channel DAC that can do so much for so little money.
If you are thinking of buying any $2000+ DAC you absolutely must consider a Transporter. It’s simply that good.
SPECS & PRICING
Logitech Transporter Network Music Player
Type: WiFi (802.11g) and/or Ethernet-connected D/A processor with digital-domain volume control (range-adjusted with resistor jumpers)
Digital inputs: TosLink, coaxial, BNC, AES/EBU, word-clock (BNC)
Digital outputs: TosLink, coaxial, BNC, AES/EBU
Analog outputs: One pair RCA, one pair balanced XLR
Operatingsystemssupported: Mac OS X 10.3 or later, 733MHz Pentium running Windows NT/2000/XP, Linux/BSD/Solaris/Perl 5.8.3 or later
Sample rates supported: 44.1kHz, 48kHz, 88.2kHz, and 96kHz
Audio formats supported: linear PCM, 16 or 24 bits/sample
Maximum output levels: 2V RMS, single-ended; 3V RMS, balanced
Dimensions: 17" x 3" x 12.25"
Shipping weight: 11 lbs.
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