Digital Processor Reviews

The Gen.V also differs from its predecessors by having a fully discrete analog output stage. Both the output buffer and the current-to-voltage converters are discrete in the Gen.V. By comparison, the Gen.III used op-amps. (The Gen.III's output buffer was the Precision Monolithics BUF-03.) In the Gen.V, matched bipolar transistors form the direct-coupled, class-A current-to-voltage and output buffer stages.

In addition, the differential amplifier that combines the two balanced phases for single-ended output is fully discrete. In fact, there are no op-amps in the signal path. However, each output stage has an op-amp used as a DC servo, eliminating coupling capacitors from the signal path.

The analog board in the balanced version is made of Teflon, which is more than ten times the cost of glass epoxy, and makes soldering more difficult; the single-ended Gen.V has a glass-epoxy board. Resistors are nearly all Vishay—the best resistors made.

Theta has maintained a policy of making their products upgradeable as technology improves. In fact, if you have a DS Pro Gen.I, you can upgrade to a Gen.V. The most common upgrade will be from a Gen.III to a Gen.V, which costs $1500 (balanced to balanced), or $2100 (single-ended to balanced) for original owners. If you bought a DS Pro secondhand, the upgrade prices will be higher.

The Gen.V is an impressive piece of audio engineering. The overall design, attention to detail, workmanship, and cost-no-object parts reflect a commitment to challenging the state of the art in digital playback.

Listening
The Generation V faced some very tough competition; lately, I've been listening to the Sonic Frontiers SFD-2 Mk.II with the HDCD decoder/filter chip, and a Mark Levinson No.30.5.

Compared to the Gen.III (with which I'd spent quite a bit of time), the V was significantly different—and better—in almost every respect. Theta products, particularly the Gen.III, have always been forceful, vivid, "Technicolor," and aggressive rather than subtle. Moreover, the treble has been a liability, sounding somewhat grainy and cold. On the plus side, Theta processors have had spectacular soundstaging, with clear delineation between instrumental lines. They've resolved the spatial information in recordings exceptionally well, throwing a huge, transparent space. Moreover, Theta bass has been second to none in depth, power, dynamic impact, and articulation. The processors' senses of pace and rhythm have also been extraordinary, giving music an upbeat, propulsive quality.

I'm happy to report that the Gen.V kept the best qualities of the "Theta sound," while greatly ameliorating its drawbacks. The Gen.V is a kinder, gentler Theta.

First, the treble was much smoother, more refined, and natural through the Gen.V. The III's tendency toward forwardness and grain was replaced by a much more subtle, delicate presentation. Cymbals had a newfound ease and smoothness, along with greater resolution of treble detail. The Gen.V was much better at resolving low-level information and inner detail, allowing me to hear the harmonic structure of cymbals. When the layer of treble grunge was removed, the harmonic structures of instruments were better resolved and more natural. The result of the V's smoothness and liquidity was a greater sense of ease and relaxation. The more subtle perspective drew me into the music to a degree not experienced with the Gen.III.

Compared to the Sonic Frontiers SFD-2 Mk.II, the Gen.V's treble wasn't quite as smooth as I heard from the tubed processor. The difference in treble purity between the SFD-2 Mk.II and the Gen.V was, however, much less than the difference between the SFD-2 and the Gen.III.

The Gen.V's soundstage can only be described as spectacular. After hearing what removing the NPC digital filter in the SFD-2 did to the sound, I'm starting to think that the quality of soundstaging heard from the Gen.V and the SFD-2 Mk.II can't be accomplished with an NPC filter. The Gen.V, with its custom digital filter, threw a huge, crystal-clear, well-delineated soundstage. The resolution of layers of depth, along with the sense of bloom around instrumental images, was superb. Image focus was razor-sharp without being analytical—a fault of the Gen.III. I think the V's ability to portray sharp image outlines without sounding analytical is the result of the V's better ability to reveal more of the air and bloom around those images. Going back to a comparison with the SFD-2 Mk.II, the tubed processor had greater depth and a wider stage, but not by much. The SFD-2 Mk.II, however, was clearly better at resolving the individual threads within the musical fabric.

In terms of bass reproduction, the Gen.V was a notch above both the Mark Levinson No.30.5 and the SFD-2 Mk.II—the Theta's extension and impact in the bottom octave was the best I've heard. Listen to the huge bass-drum whacks on Frank Zappa's Exercise #4, from the orchestral concerts recorded on The Yellow Shark (Barking Pumpkin R2 71600): the Theta had greater dynamics, and more "meat" at the extreme bottom end. Also, the bass drum on Michael Ruff's Speaking in Melodies (Sheffield CD-35) had a greater solidity, and cut through the bass line better.

The Gen.V's midbass was also very detailed and articulate—more so than that of the SFD-2 Mk.II. The intricate bass-playing on John McLaughlin's Qué Alegría (Verve 837 280-2) was tauter, quicker, more detailed, and better resolved through the Gen.V. The SFD-2 was a little slower, fuller, rounder, and had more bloom; the Gen.V was leaner and faster, yet had a full measure of power and drive.

Perhaps because of these qualities, the Gen.V's pace, rhythm, and timing were terrific. The music had a snap, an upbeat quality, that made listening more of a physical, visceral experience. Roscoe Beck and Tom Brechtlein play some terrific bass and drums on Robben Ford and the Blue Line (Stretch/GRP STD-1102); through the Gen.V, I could hear the rhythm section lock in and propel the music forward.

Just as the Gen.V's treble was more refined, the midrange was more liquid. Instrumental textures were softer, rounder, and lacked an electronic edge.

The Gen.V excelled at detail resolution compared to most processors in its price range. There was simply more music with the V than with the III, and the presentation of detail was more subtle and understated, giving the music more ease and involvement. The fine filigree of detail heard from the very best processors was evident in the Gen.V. Overall, I greatly enjoyed my time with the Gen.V—it was consistently musical and engaging, particularly its powerful rhythmic drive.

I evaluated the LaserLinque optical option by listening to the Gen.V fed via AES/EBU from the Mark Levinson, via coax from the Theta Data Basic, and through the LaserLinque optical output from the Data Basic. The coax connection was by far the least good of the three—the treble became more forward and grainy, and the soundstage shrank. The impression of space between instrumental images was greatly reduced with the coax.

It was a close call between the Mark Levinson No.31 with AES/EBU and the Data Basic with LaserLinque optical. Both had wonderful space, transparency, and clean treble, but the No.31 had better bass definition and a more coherent, natural sound overall. Still, a Data Basic transport, the LaserLinque output option for it, and the LaserLinque input option on the Gen.V, cost $3350–$5000 less than the No.31. If you can afford it, the LaserLinque is worth the additional cost.

Conclusion
The Theta DS Pro Generation V—which provides a major improvement in sound quality over its predecessor, the Generation III—represents a sonic turnaround for Theta, with less of a distinctive character. The smoother, more laid-back Gen.V resolves more detail than, and has a refinement lacking in, the Gen.III. While making their top-of-the-line processor less vivid and incisive, Theta managed to maintain the hallmarks of their products: spectacular soundstaging, the best bass reproduction in digital playback, and a wonderful sense of pace and drive.

The most challenging competition comes from the $5295 Sonic Frontiers SFD-2 Mk.II, now fitted with the High Definition Compatible Digital;r (HDCD) decoder/filter. In a comparison with non–HDCD-encoded discs, the Sonic Frontiers had smoother treble, a bigger soundstage, greater ability to resolve individual images from the whole, and higher resolution of low-level detail. The Gen.V had deeper bass extension, more articulate and detailed midbass, greater dynamic impact, and a more powerful sense of pace and rhythm. Playing HDCD-encoded music was no contest—the HDCD decoder elevated digital playback an order of magnitude. For my system and tastes, combined with the inclusion of the HDCD decoder, I would choose the SFD-2 Mk.II; but there's no question that Gen.III owners should upgrade to the Gen.V. (Note also that Theta has acquired a licence to use HDCD technology.)

I regard the Generation V as one of the best five or six digital processors I've heard—and most of the others cost much more than the Theta. The Gen.V is a must-audition for anyone looking for the best in digital playback.—Robert Harley