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Without hearing the effect of the separate sync cable, one would not suspect something was missing. But plugging it back in returned the magic and threw into sharp relief the Linn's best attributes. These impressions were repeated with a variety of music. It's tragic that a separate sync cable was not made part of the S/PDIF standard. Just because the mass market chooses to ignore this source of major improvement, the High End shouldn't accept this compromise. All high-end digital transports and processors should have a separate sync cable (footnote 2).
Sidebar 1: In Sync!
The Linn CD player completely sidesteps a problem that plagues all other CD transport/processor combinations: jitter in the recovered clock. Linn's method is so simple I'm surprised no one else has done it before. In fact, I'm surprised that the S/PDIF (Sony/Philips Digital Interface Format) standard didn't incorporate this technique when the interface standard was established. But before looking at Linn's solution, let's see how a conventional transport and D/A converter interface works.
The S/PDIF output of a CD transport—the RCA jack marked "Digital Out"—…
Sidebar 2: 1992 Review System
I auditioned the Linn CD player with three different pairs of loudspeakers that made their ways through my listening room over the past weeks: the Monitor Audio Studio 20 reviewed last month, the Apogee Centaur Minor reviewed in this issue, and my reference system, the Hales System Two Signatures augmented by a Muse Model 18 subwoofer. VTL 225W monoblocks were the primary amplifiers—a Jeff Rowland Model One saw brief action—and an Audio Research LS2 line-stage preamplifier provided gain and switching control. Interconnects were Straight Wire Maestro and…
Sidebar 3: 1992 Measurements
The Numerik put out 2.135V when decoding a full-scale, 1kHz sinewave. This is only slightly higher (0.57dB) than the CD standard of 2V. Channel balance was the best I have measured, the right channel being just 0.004dB higher in output than the left. Digital converters often have a few tenths of a dB channel imbalance.
Frequency response (fig.1) was flat, rolling off an almost negligible 0.5dB at 20kHz. Note the virtual overlap of the left and right traces, confirming the almost perfect channel balance. Fig.2 is the Numerik's de-emphasis error. A…
Robert Harley wrote again about the Karik/Numerik in October 1994 (Vol.17 No.10):
Back in January 1992 (Vol.15 No.1), I reviewed the Linn Karik CD transport and Numerik digital processor pair, the first digital components from Linn Products of Scotland. I found them eminently musical, technically sophisticated, and worthy of a Class A recommendation in Stereophile's "Recommended Components."
Although the Karik's mechanism and electronics remain unchanged, the unit is now a CD player as well as a transport. Linn simply installed a D/A board without increasing the $3395 retail…
Because of the rapid turning on and off of their transistors, switching supplies radiate high-frequency noise, some of which gets into and pollutes the adjacent audio circuits, which is one reason they generally haven't been used in audio components (footnote 2), [David Berning's amplifiers are the only high-profile designs to use switching supplies since the demise of the Infinity and Sony PWM amplifiers.—Ed.] Linn believes that they've overcome this limitation, claiming not only to have solved the radiated noise problem, but also suggesting that the new power supply "transforms" the…
Finally, the SPS Numerik presented the music on a blacker background—the music existed in dead quiet, rather than being superimposed on a slightly gray canvas.
Although I preferred the PCM63-fitted Numerik to one with the 1702 DAC, I heard none of the objectionable characteristics when the PCM1702 was combined with the SPS. The treble was pure and clean again, and the midrange was restored to its former liquidity. Linn has really hit on something with the switching power supply. I'm forced to agree with their claim that the new supply "transforms" the sound of the Numerik.
Next,…
Sidebar 3: 1994 Measurements
The Karik had a maximum output level of 1.96V when playing a full-scale, 1kHz sinewave. Its output impedance measured just under 100 ohms at any audio frequency. DC-offset levels were below the voltmeter's sensitivity, implying that any DC was less than 500µV. The Karik doesn't invert absolute polarity; a positive-going impulse on a CD produces a positive-going impulse at the Karik's analog output. Frequency response and de-emphasis error (fig.1) were both excellent. Unlike most players, the Karik had no rolloff at 20kHz. The de-emphasis circuit had a…
Fig.8 is the Numerik's frequency response and de-emphasis error. The processor rolls off half a dB at 20kHz, and the de-emphasis circuit has a 0.3dB positive error in the treble. The result will be a slight brightening of the sound when playing those rare discs recorded with emphasis. Crosstalk performance (fig.9) was excellent, with 100dB of channel separation at 1kHz, and holding to better than 100dB at any audio frequency.
Fig.8 Linn Numerik, frequency response (top) and de-emphasis error (bottom) (right channel dashed, 0.5dB/vertical div.).
Fig.9 Linn…
Sidebar 4: Specifications
Description: Remote-controlled two-box (transport and processor) CD player. Conversion: dual 20-bit ladder DACs. Digital filtering: 8x-oversampling. Audio specifications: none provided.
Dimensions: 12.5" W by 3" H by 13" D (each box, not including rear-panel connectors).
Price: $5590. Approximate number of US dealers: 100.
Manufacturer: Linn Products Ltd., Floors Road, Waterfoot, Glasgow, Scotland G76 0EP, UK. Web: www.linn.co.uk. US Distributor: Audiophile Systems, Indianapolis, IN (1992); Linn Inc., 8787 Perimeter Park Boulevard, Jacksonville, FL…