Hi-Rez Disc Player/Transport Reviews

At the 2019 AXPONA, I took part in one of my first official meetings, as editor of Stereophile, with members of the manufacturing community: the German company T+A. They were presenting in the room of Texas dealer Lone Star Audio, which was owned by the late Jim Hench. They had a corner hallway to themselves: two rooms and, at the time when I arrived, a hallway table brimming with coffee and pastries. Fortuitous timing.

In one of those rooms I saw some of the company's less-expensive gear: I stopped in briefly—yet I spent so much time in their high-end room that I lost track of my coffee cup, setting it down somewhere while freeing up a hand to take some pictures.

It was an impressive room. Attractions included the unusual T+A Solitaire loudspeaker, with its line-source electrostatic tweeters and its array of midrange drivers, and the very architectural M 40 HV monoblock tower, with its heavy tube cages on top.

Yet I was most taken by two big, beefy, silver cases sitting on a component rack. Both were new components from the company's reference HV series. One was a CD/SACD transport, the PDT 3100 HV; the other was the Reference streaming DAC/Preamp: the SDV 3100 HV. The scale was impressive: the casework, the sheer quantity of aluminum on display, the apparent engineering.

I was also impressed to learn that the DAC/Preamp had a built-in FM tuner. I love FM tuners, even though—perhaps especially because—I can't use them. More on that later.

The 3100 series includes several other components: a standalone transport (the PDT 3100 HV), a streaming DAC sans preamp (the SD 3100 HV), an integrated amplifier (the PA 3100 HV), and the component under review, the versatile MP 3100 HV SACD player/streaming DAC ($21,000).

A systems approach
T+A is not as well-known in the United States, but in Germany the company is huge. To this American, they appear to fulfill the key German stereotypes: fastidious, with an engineering focus. T+A stands for "Theorie und Anwendungen"—in English, "theory and application."

Evidence of the company's engineering focus can be found in the way their product lines are differentiated, less by quality or price point than by functional approach. There are six distinct lines, plus the Caruso: an all-in-one audio system that's a product line in itself. Series 8, for example, consists of "high-end individual modules"; the K-Series encompasses "ultra-compact equipment boasting multiple functions and outstanding sound qualities"; the Cala series is for people who "require sophisticated design, excellence of craftsmanship, simplicity of operation and compactness"; Cala customers, the website suggests, "cannot even contemplate the typical large systems assembled from separate components."

Those who can contemplate such systems, and who wish to avoid sonic compromise, are encouraged to explore the HV series—including the MP 3100 HV. "The HV-series is the true embodiment of the original meaning of the term 'high-end': innovative technologies, uncompromising construction and absolutely peak performance," claims the T+A literature.

Danger: High voltage
"HV" stands for "high voltage." It's a technical concept that arose during a period in the company's history when the focus was on tube gear—specifically, the tube-based V series, which was successful until they started to run out of tubes.

"Over the years T+A created tube products, our engineers concluded that one of the most important factors in the sonic quality we achieved from tubes was the very obvious fact that they operate on much higher power supply rails than typical of solid-state," T+A's Jim Shannon wrote to me one day, in an email I believe was sent from Kuala Lumpur. "This allows the tubes to operate in a much more linear, low distortion, narrow portion of their total transfer function—essentially the sweet spot of the transfer function, which in turn offers greater dynamics, greater harmonic purity, and greater overall musicality (footnote 1). Our design team decided to build test units using solid-state devices that were capable of operating at the much higher voltages, and learned that the same kinds of benefits could be found using solid-state devices." When they combined this idea with other concepts they'd learned improve the sound—fully balanced circuitry, dual-mono architecture, low global feedback—the HV series emerged.

The idea of operating transistors at higher voltages is most relevant to amplifiers, but it also applies to output stages in source components. In the MP 3100 HV and the other HV source components, "the fully balanced, dual mono analog output stages are all using much higher voltage power supply rails," Shannon told me.

More than any other component I've had in my system, the MP 3100 HV radiates attention to detail. Start with this: There are two IEC connectors, for two power cords, one on each end of the back panel, feeding two power supplies. One supports the analog circuitry, the other the digital circuitry. Never the twain shall meet.

What makes a good digital source?
What are the most important technical details to address in a high-end source component? I'm not a designer, but I do know the conventional wisdom. At the top of the list is the D/A conversion technology. D/A conversion can be done, and done well, in a number of different ways—with high-quality chip DACs, or novel calculations carried out on an FPGA, or a combination of the two, with filters custom-coded off-chip. But success depends on optimizing whatever approach is taken: It's all in the execution.

After the conversion technology, there's a crucial second tier of priorities. At the top of that list, I'd place what I'll call signal-conditioning: ensuring that the electrical signal remains undisturbed by distortion and noise, whether arising from inside the box or from outside. After that in my priority list comes vibration isolation: isolating the transport from the environment and the environment from the transport, but also protecting circuitry from airborne and structure-borne vibrations. Why do vibrations matter? Because they can induce noise in the electrical signal.

Inasmuch as conversion technology is concerned, the MP 3100 HV maintains totally independent paths for pulse-code modulation (PCM) and pulse-width modulation (PWM, or DSD) data. The DSD side utilizes true, pure single-bit bitstream conversion. Via the USB input, the T+A is capable of converting up to DSD512 natively, no PCM encoding (ie, DoP) required. But to get that to work—to get native DSD data into the box—you'll need to use the USB connection and a data source that can run a Windows 10 driver—at a minimum, a Windows-based computer running Roon Bridge and that driver. It doesn't need to be powerful.

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Footnote 1: At one point, Shannon described this operating region as "low-distortion, harmonically rich"—a fascinating juxtaposition of technical and subjective concepts.