Theta Jade CD transport Measurements

Sidebar 3: Measurements

There is little to say about the Jade's measurements. The digital output waveforms looked clean and fast when correctly terminated and viewed on an oscilloscope. Jitter measurement is a function of the decoder used, and can't be specifically determined for the transport alone.

Immunity from shock and vibration were very good, but error correction was barely average. While the absolute minimum Red Book standard is 0.2mm of missing data, in fact most players amble through 1.5–2.5mm, and some generations of Philips CD "engines" even navigate 4mm of correctable error gap. The Jade was very happy up to 0.75mm, but ducked the 1mm-gap entry on the Pierre Verany test disc. In practice, however, only discs with pretty severe damage will fail to play. In my experience, the sound of such discs is already beginning to deteriorate, owing to the constant extra workload on the error-correction and drive, and not least the degraded S/N ratio seen in the output of the optical reading diode.

And, as I've found when reviewing other transports, you can't really maximize performance until the other units present for comparison are turned off, even disconnected. Likewise, there is a small but discernible sonic price to pay when connecting two wired digital sources to one decoder. There is always some interaction, unless both use fiberoptic interconnects.—Martin Colloms

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