Digital Processor Reviews

Parts quality is very high. The capacitors associated with the Bitstream DAC are primarily polystyrene, all resistors are 1% metal-film types, and four of the resistors in the feedback loop are $3 non-inductive wirewound types. These resistors reportedly had a huge effect on the Prime's sound quality. In addition, a few Teflon capacitors (very expensive) are used in critical audio stages. The metal work is zinc over copper over steel, and the pcb is glass epoxy.

Overall, the Prime is an engineering marvel for its modest price. There is far more inside the unit than one would expect for $1250. Theta was reportedly able to keep the Prime's price low by several techniques: buying parts in large quantities with the expectation of selling lots of units, minimizing internal wiring and thus reducing labor costs, using the Philips Bitstream chip instead of a pair of multi-bit ladder DACs, ordering all the metalwork at one time for a lower price, and cutting their profit margin on each unit with the hope of recovering it by quantity sales.

Music
I didn't know what to expect musically from the Prime. On one hand, Theta's DSP-based multibit-DAC processors have always had common family traits: deep and driving bass, spectacular soundstage resolution and three-dimensionality, and dynamics galore. On the other hand, Bitstream-based D/A converters I've auditioned tended to have the opposite characteristics: somewhat soft bass, limited dynamics, and less resolution of individual instrumental outlines. Even the best of the Bitstream processors—the Meridian 203, in my opinion—has these Bitstream-like sonic qualities but is eminently musical in its own way. The Theta processors grab the listener, the Meridian Bitstream converter coaxes him. What would the software-based, Bitstream DS Pro Prime sound like?

It was immediately obvious that the Prime was much closer in sound to Theta's previous processors than other Bitstream products I've heard. In fact, the presentation was instantly identifiable as a Theta: a huge transparent soundstage and stunning sense of space and depth. Switching to the Prime transformed the presentation; it was like going from hearing the music through a rectangular frame to having the frame removed, leaving only the music.

This sense of size and space was clearly the Prime's forte. Listen to Jack DeJohnette's Parallel Realities (MCA MCAD-42313). The spacious and ethereal drums moved back about 20!0, making the rear wall seem to vanish. The percussion on "Dancing" suddenly seemed to exist on its own in space, rather than fused with the rest of the performance. In addition, there was a crystal-clear transparency nothing short of stunning. The Prime provided a huge, clear window on the music, unfettered by any sense of haze or veiling. In addition, the Prime threw clearly focused image outlines in three dimensions, infusing the music with a sense of realism. The presentation was anything but flat and sterile.

I could go on, but you get the idea. In short, the Prime's soundstage presentation and resolution of spatial cues were rare to hear from any digital processor, never mind one that costs $1250.

After getting over the Prime's stunning soundstage, the next aspect that grabbed my attention was the unit's dynamics. The Prime presented an effortless feeling of power, allowing the music's dynamics to more fully express themselves. There was a razor-sharp edge to transients, coupled with an ability to reveal wide dynamic contrasts. The result was a sense of suddenness, immediacy, power, and life. These qualities tended to make listening an active participatory experience, rather than a casual endeavor. In this regard, the Prime sounded very "un-Bitstream."

In the area of bass reproduction, there was no mistaking the Prime's lineage. Like other Theta processors, the Prime presented a rock-solid low-frequency foundation for the music. The bass was tight, punchy, deep, and very well defined. Kick drum had an impact that rivaled that of the extraordinary Wadia 2000, and bass guitar had a tautness that gave the music a sense of drive. The combination of bass solidity and effortless dynamics gave music a powerful sense of drive and urgency, the antithesis of bland, sluggish, and plodding. In addition, LF pitch resolution was superb by any measure, revealing tonal nuances obscured by other processors. Again, the Prime sounded like no other Bitstream-based converter I've auditioned.

The Prime's treble was smooth and less hard than many other processors, but lacked the ultimate sense of ease heard from analog and some D/A converters, albeit more expensive ones. I found the treble smoother and more natural than the PS Audio SuperLink, for example, but not as delicate and refined as the Audio Research DAC1-18. There was also less inner detail revealed through the Prime than the DAC1, the latter processor tending to resolve another layer of musical information. This gave the Prime's treble less of a lifelike quality, especially when reproducing instruments with significant high-frequency content. The DAC1's superior resolution of fine detail also gave it an edge in reproducing a sense of soundstage depth. While the Prime was superb in rendering three-dimensionality and depth, the DAC1 seemed better at presenting an ultimate sense of distance, a phenomenon perhaps related to the DAC1's better ability to discern the finest of inner detail.

I found the Prime's rendering of instrumental textures good, but not outstanding. There wasn't that lushness in the mids that characterizes the VTL Reference D/A and Audio Research DAC1-18. While instrumental textures were detailed and well fleshed out, they lacked the naturalness, ease, and liquidity that characterize digital processors based on the UltraAnalog DAC. Remember, though, that these comparisons are with converters costing two and a half to nearly six times the Prime's price. There's always a tendency to compare a modestly priced superachiever like the Prime to more expensive products rather than those in its own price range.

The bottom line is that I enjoyed listening to music through the Prime. During direct comparisons with other processors, I repeatedly felt a strong desire to return to the Prime and enjoy the music. I felt compelled to listen to entire CDs through the Prime, rather than continue the comparisons with the same track of music. This is a sure sign that a product is fundamentally right musically—a sign that was unmistakable with the Prime.

Conclusion
At $1250, the Theta DS Pro Prime represents another significant increase in the price/performance ratio of digital processors. It clearly outperformed every processor in its price range, and rivaled those costing much more. Its overall performance was better than that of Theta's DS Pro Basic, a unit that itself brought a new level of performance to a sensible price. In fact, processors with the Prime's sound and costing as much as $3000 would still receive a recommendation.

The Prime's strengths are many: robust and powerful bass, smooth tonal balance, and best of all, a stunning presentation of soundstage. This last quality is the Prime's highlight. Its ability to reveal spatial cues within a huge, transparent soundstage was remarkable, and easily superior to processors costing many times more.

I must add a caveat: The qualities that I find appealing in the Prime (and other Theta processors) may not suit all listening tastes. The razor-sharp soundstage focus, vivid tangibility of instrumental images, and slight forwardness may be less musical to some music lovers than the more laid-back, relaxed, and softer presentation provided by, for example, the Meridian 203 and Audio Research DAC1-18. In addition, the Prime is not the last word in portraying textural liquidity.

In addition to its superb sonics, the Prime is solidly built. It does, however, lack such features as polarity reversal and multiple coaxial inputs. Given the choice of better sonics or inclusion of these functions at the same price, the music enthusiast must choose sonics. Incidentally, the Prime works very well with Theta's Data transport (also reviewed in this issue). With a retail price of $3650 for the pair, it is, in my opinion, the best value going for a transport/processor combination.

If you're in the market for any digital processor, the Theta DS Pro Prime must be auditioned. Your ears and your bank account may be in for a pleasant surprise.