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Today is Monday, February 5, and it's so buttercupping cold outside that the custodian couldn't get our school's oil burner started. Consequently, my daughter is home for the day, playing on the rug in front of the fireplace. (Santa brought a wooden castle and a fine selection of medieval figurines, some of which are headed for the dungeon as we speak.) I'm at my desk in the music room, on the upwind side of the house—and the wind is murder. The west wall is cold. The north wall is cold. The floorboards are cold. But the air inside is warm as toast: I'm driving my Quad ESL speakers with a…
More or less the same mu-follower circuit—doubled up and configured as a differential amplifier—is used to drive a Circlotron output section in all Joule Electra OTL amps. Notwithstanding his admiration for Karsten's single-stage OTL, Barber opted for extra gain so that he could apply a little negative feedback—or at least give the user an option to dial it in. Even without feedback, the 80Wpc VZN-80 amplifier I've been using has a usably low output impedance of 10 ohms. This is accomplished by using multiple output tubes in parallel—in this case, the already-low-impedance 6C33C—in which…
Ever since Vol.6 No.3 was published in August of 1983, Stereophile has been the leading subjective review magazine in terms of circulation. At that juncture our circulation was 12,000 and has now increased to 15,000. And it's all your fault!
I would like to particularly thank all the faithful subscribers who have been with Stereophile since way back. That core of readers has supported this magazine both morally and financially through some real hard times. Starting with JGH's move to Santa Fe in 1978, issues of your favorite magazine came few and far between. Three "quarterly" issues (Vol…
The rumors have been flying, and his arrival is imminent—a couple weeks after you read this—so it's time our readers know: John Atkinson, for the last four years Editor of Britain's prestigious Hi-Fi News & Record Review (left), is joining the staff of Stereophile as Managing Editor and International Editor.
You can imagine how exciting an event this is for people here. John is respected far and wide in the field of audio journalism, and is credited for establishing HFN/RR as the premier audio journal of the English-speaking world. (I feel it's the best in any language.) John is also…
Many pundits in our industry say that CD is under threat from Super Audio CD, DVD-Audio, and dual-layer CD/DVD technologies. Conflicting stories abound, and even though I'm supposed to be well-informed, I've found some of them hard to sort out! For example, Michael Fremer, concluding a fine review of the $7500 Bow Technologies ZZ-Eight integrated CD player in August, compared its notable 16-bit/44.1kHz achievement with a DVD-based disc originally mastered at 24/96kHz and replayed on an inexpensive DVD player. He found the Bow wanting in some respects. What is the world coming to?
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Sidebar 1: Specifications
Description: Single-disc CD transport with remote control and coaxial (phono), coaxial (BNC), and balanced AES/EBU (XLR) data outputs. AT&T optical output is optional.
Serial number of unit reviewed: 18527.
Price: $2495 (1999); no longer available (2007). Approximate number of dealers: 75.
Manufacturer: Theta Digital Corp., 5330 Derry Avenue, Suite R, Agoura Hills, CA 91301. Tel: (818) 597-9195. Fax: (818) 597-1079. Web: www.thetadigital.com.
Sidebar 2: System
Working back from the sound in air, launched by Wilson WITT 2 speakers via Transparent XL cables: the power amplifier was a Krell FPB 600, driven either by directly controllable decoder outputs or via a Conrad-Johnson ART preamplifier. These decoders included that of the Krell KPS-25i, referenced to a dCS Elgar and the Audio Synthesis DAX Decade (configured for HDCD and full balanced operation). Comparison transports include the Krell and a trusty if discontinued Meridian 200, these also referenced to my assessment of the Theta Basic II transport.
Digital…
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…
Rumor had it that if the MF2500 amplifier had gotten any better in development, Conrad-Johnson would have had to include it in their "Premier" series. However, C-J's intention was to hold to the lower price of their established MF series, and so they have. Rated at 240Wpc and retailing for $3495, the '2500 is the core model of Conrad-Johnson's current range of "MF" power amplifiers. Its companion MF2250 offers 120Wpc, while the MF5600 delivers 120Wx5 for multichannel home-theater applications.
Like many Conrad-Johnson designs, the MF2500's higher performance goals have been attained…
Sidebar 1: Specifications
Description: Solid-state stereo power amplifier. Maximum output power: 240Wpc into 8 ohms (23.7dBW), 20Hz–20kHz, at less than 1% IMD or THD. Frequency response: 20Hz–20kHz, +0/–0.1dB. Hum and noise: 100dB below rated output. Input impedance: 100k ohms.
Dimensions: 19" W by 6.75" H by 16" D. Weight: 55 lbs.
Serial number of unit reviewed: Not noted.
Price: $3495 (1999); no longer available (2007). Approximate number of dealers: 80. Warranty: 3 years.
Manufacturer: Conrad-Johnson Design, 2733 Merrilee Drive, Fairfax, VA 22031. Tel: (703) 698-8581. Fax…