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 Generation VIII


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Theta Digital





Preamplifier/D-A Convertor, RC, SACD & DVD ready


The Generation VIII has all of the sonic benefits of an "upsampling" processor, and none of the drawbacks.

Upsampling, a term from the professional recording industry, refers to a box added between a digital source and a converter. The "upsampler" allows "noise shaping," and adjustments of other parameters in a digital signal. Typically it provides 2x oversampling to the signal in order to have the "headroom" to do the noise shaping.

The interesting thing about these outboard boxes is that users can listen to the differences it makes when you adjust, for instance the sample rate conversion from 44.1KHz to 48z. You could call it the digital equivalent of an analog equalizer -- both good and bad. Bad systems can benefit from them, but the more accurate the system is, the more likely the box is to introduce degradation.

An "upsampling" digital signal processor can only improve sound in one way, a nd that is by oversampling. What oversampling does is to resample the signal so many times that digital artifacts ("images") are forced far away from the audible spectrum as the calculations are taking place to process the signal into analog. Theta’s sophisticated processes do this in a number of steps to get the finest results possible.

The oversampling provided by an outboard box is redundant in a high quality system: Generation VIII’s multi-stage digital filter brings the signal up to 384KHz. Fewer boxes, of course, means less degradation of the signal by jitter. Theta’s digital filtering, using very meticulously crafted algorithms running on high powered computer chips, is superior to filtering done by the asynchronous filter chip typically used in outboard "upsamplers".

f you would like the entire explanation complete with diagrams that demystify this subject, please visit Theta's web site and read the white paper on "Upsampli ng".

What does that mean? In essence, each channel is really two mirror imaged signal paths.

In Gen VIII, digital signals are "balanced" before they are processed: the mathematical signal is cloned, and the phase-inverted duplicate processed through a path identical to its twin.

The two signals stay separate until they are united at the end of the signal path, canceling out noise. In a full Theta system, the signal stays balanced and separate up until it goes to your speakers.

Discontinuities arise in the course of processing, but do not survive in a balanced/differential circuit.

Anything not exactly "mirror imaged" between the two signals is eliminated (called "common mode rejection"). This preserves the integrity of the signal in a way that no other procedure can.

This no-compromise technique is rarely used, however, because it requires almost twice as many devices as conventional processing.

Most companies will not do this rigorous a job *. We wouldn’t invest this much in high quality components either, if we could figure out an easier way of getting such pristine results.

The circuitry stores all digital audio in a buffer where the signal aligns perfectly and then reclocks it to the DACs using a high-precision crystal oscillator and DSP algorithm. The resulting rock-stable digital audio suffers none of the problems associated with ordinary, jitter-prone processors.
What is Jitter?

Jitter is one of the major factors in the degradation of digital signals.

As data streams make their way through circuits, connections and components, they have a tendency to become temporally misaligned. This is an inherent vulnerability. The errors tend to be cumulative, and as the misalignment worsens, it can become impossible to correct.

These timing errors, which we call jitter, translate into harmonic distortions to the music.

 Once incorporated into a musical signal, these errors are inextricably part of what you hear, and since they are mathematical artifacts unrelated to music, the sound can be quite stressful to endure. Even when jitter is reasonably low, rather than providing you with a headache, these residual errors can cloud the music and dirty up the sound, taking away the spirit of the music.

Maintaining signal integrity

Theta uses many methods to minimize jitter at points where the signal is particularly vulnerable. All digital signals are reclocked as they come in to any of Theta’s D to A processors. Theta deals in other ways with jitter problems originating in transports.

Maintainingsignal integrity all along the digital chain is the goal.

"Jitter Jail" technology, introduced in 1998, was a revolutionary new tool developed as an even more effective technology than reclocking the signal "on the fly". A custom-manufactured low-jitter crystal oscillator at its heart, Jitter Jail acts as a buffer, actually storing the digital signal long enough to reclock it much more perfectly than we can do as it is streaming by.

The circuit’s master clock realigns data, correcting raw data as it comes from the disc.

This high-precision buffer becomes your source, rather than the CD, which has jitter problems of its own. CDs are not physically perfect, and the recording and editing leading up to the CD has it's own accumulated jitter. The pits are unevenly aligned, there are deformities in the material of the substrate, and the clear plastic is not perfectly clear. By reclocking the data from your CDs you can actually recreate a truer representation of the music, as it was created, than the raw data coming direct from the CD.

*Some digital components from other manufacturers have XLR connectors
on their back panels but are not balanced. The connector is no
indication that there are even partially balanced circuits inside.
Jitter Jail Theta's proprietary Jitter Jail technology virtually
eliminates jitter.