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There are only three questions to be asked of a digital/digital converter set to upsample "Red Book" CD data: 1) does it add high-frequency information above the Nyquist Frequency (half the sample rate) of the original data? 2) Does it add low-level information below the original word-length limit of the original data? and 3) does it increase or decrease the level of word-clock jitter in the datastream? If it does increase the jitter level, then, regardless of any other effect it has, the sound may well be worse.

As you can read in our February 1999 review…

Setting the Purcell to upsample the CD data to 24-bit/96kHz and driving the Elgar with a double-speed AES/EBU link almost doubled the jitter level, to 325ps. This is still low, but reflects the fact that the effect of jitter in the datalink increases with increased sample rate. I…

"Dear Mr. Scull," it began. Okay. So far, it didn't feel like an e-mail written with a hot temper and clenched teeth. "I look forward to 'Fine Tunes' each month when I receive my copy of Stereophile..."

Something about the August and September installments had resonated with TJZ regarding laser-alignment tools, and he had a great tweak he…

Or are they? While the industry-feminizing tiny triode set has made a great deal of noise in the past few years (I can hear them hissing now), soft-walking, big-stick-carrying, mega-power amplifiers still circle the globe.

Softspoken audio veteran Nelson Pass has been building such behemoths for years. Between 1993 and 1998, his Pass Laboratories marketed…

Description: Solid-state monoblock power amplifier with class-A output stage. Output power: 160W into 8 ohms at 1kHz, 1% THD (22dBW). Frequency response: 1.5Hz-100kHz, -3dB. Distortion at 1kHz: 0.01% at 10W and 100W, 1% at 160W. Maximum output voltage: approximately ±50V. Maximum output current: approximately ±12 amps. Input impedance: 22k ohms balanced, 11k ohms unbalanced. Voltage gain: 26dB. Damping factor: 30 ref. 8 ohms nominal (equivalent to an output impedance of 0.27 ohm). Slew rate: approximately ±50V/µs. Dynamic range: 155dB (random noise floor to peak…

Analog source: Simon Yorke turntable; Graham 2.2, Immedia RPM2 tonearms; Transfiguration Temper W, Lyra Helikon mono, Lyra Titan cartridges; Linn combo of Sondek, Ekos, Aktiva, Lingo, Linto.
Digital source: Musical Fidelity Tri-Vista SACD player, dCS Verdi-Purcell-Elgar SACD combo.
Preamplification: Manley Steelhead, ASR Basis Exclusive phono sections; Halcro dm10 preamplifier.
Power amplifiers: Halcro dm68, Musical Fidelity KW monoblocks.
Loudspeakers: Audio Physic Avanti III, Wilson Audio WATT/Puppy 7.
Cables: Phono: Hovland Music Groove,…

The big Pass Labs XA160 ran very warm, its chassis being almost too hot to touch after the usual one-hour preconditioning at one-third power (53W) into 8 ohms. Interestingly, the distortion rose very slightly during that period, from 0.14% to 0.2%, but as it plateau'd rather than continuing to rise, I imagine this reflects the amplifier's transfer function settling in as the active devices came up to their operating temperatures.

The XA160's voltage gain into 8 ohms was 26.25dB for both balanced and unbalanced signals. (I shorted pins 1 and 3 of the XLR…

Spoiled. K-10 and I are so spoiled.

Studio Traps or no, I found the very top of the No.32's frequency band a hair less alight and bright than those of some other preamps. But again, the beauty of the…