Theta Digital DS Pro Prime D/A Processor (DAC)

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Theta DACs have quite a following and we never seem to be able to keep them in stock.

These days it's hard to find a better sounding dedicated DAC for Redbook CD reproduction, as most focus entirely on Hi-Res audio.

The Prime is working absolutely perfect and looks great with little to no signs of use.

This specific model was introduced in the 1990's when it retailed for $1250.

It will be shipped to you in its original box.

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - XLR Interconnects 

Kimber Kable - Coaxial Digital Interconnect

Kimber Kable - Optical Digital Interconnect

Kimber Kable - Base Series PK14 Power Cord - Brand New

More from Theta Digital:
DS Pro Prime
One-bit technology was headline news around this time. It was touted by major hi-fi manufacturers as being the next revolution in digital sound. They said multi-bit technology was dead.

Theta’s design team tried this new technology in high-performance designs and found it smooth sounding but lacking in aliveness, dynamics and bass. They envisioned one-bit technology as a palliative for less expensive products. Most inexpensive CD players and outboard D to A converters sounded shrill and harsh.

The smoothness of the one-bit D to A could be implemented to reduce “glare” and other irritating characteristics, to bring new musicality to otherwise unacceptable components. It meant Theta had something to offer in a price realm previously thought hopelessly compromised.

The DS Pro Prime was introduced in May of 1991. The Prime was similar to the Basic in construction, different in circuit design. It had a single circuit board which contained the power supply, digital and analog sections. The digital section employed a single Motorola 56001 microprocessor running at 30 MHz.

It was a 4x-oversampling unit and thus didn’t have the huge amount of information presented in the Basic or the Generation III. Compared to other D to A converters in its price class, however, it was nothing short of a miraculous improvement.

Where previously there was only harsh, strident sound, lacking in detail, there was now musicality and enjoyment.

From a 1991 Stereophile review written by Robert Harley:
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.

Music
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.

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.

Technical Specifications
4x-oversampling software-based D/A processor with Bitstream DAC

Digital filter:
4x-oversampling Theta composite filter using one Motorola 56001 DSP chip.

D/A conversion:
64x-oversampling Philips Bitstream DAC

Frequency response:
DC–20kHz +0dB, –0.4dB

THD+N:
104dB at 1kHz referenced to full scale

Output impedance:
50 ohms

Dimensions:
19" W by 2.5" H by 10.5" D.

Weight:
14 lbs net, 16 lbs shipping.

The SkyFi Testing Process for DACs:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating.

After the visual inspection we connect the DAC’s RCA outputs to our Sencore PA81 Power Analyzer which simulates a real world input impedance and allows us to monitor the output on an oscilloscope. We are equipped to test optical, coaxial, and USB inputs at Redbook CD Quality. We start with a test signal to verify signal lock and proper output on both channels. If the DAC has balanced outputs these are also tested at this time. If the DAC has multiple Optical and Coaxial inputs they are all checked for proper lock. USB inputs are tested with a Macbook Pro.

After proper function is verified, we set the DAC up for a listening test to evaluate general audio reproduction quality and monitor for clicks, pops, or any other audible signs of issues related to dropped signal lock or failing audio output stages. We often connect DACs under evaluation to our long term test rig for a long test stint to verify stability under real world operating conditions.