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The tape outputs are buffered using IC op-amps in a unity-gain voltage-follower configuration. As with the GTP-400, I applaud Victor Campos's insistence on the use of tape output buffers. They are absolutely essential if the integrity of the internal signal path is to be maintained. The loading of the circuitry caused by tape recorders—particularly if they are switched off—and cable capacitance can seriously impair the performance of an otherwise excellent design. Every preamp claiming high-end performance should have actively buffered tape outputs, but many, including the older GFP-555,…
The GFP-565 phono preamp does nothing to exaggerate clicks, pops, or other forms of LP surface noise, indicating that such transients are not driving the preamp into non-linear operation or, if they are, the preamp's recovery is virtually instantaneous. The neutrality of the tonal balance will depend strictly on the cartridge used, since you'll be hard pressed to find a preamp with flatter RIAA equalization. This phono preamp is an excellent vehicle for revealing the differences between phono cartridges, not only in terms of tonal balance, but in other aspects of performance as well. The…
Followup from October 1990 (Vol.13 No.10):
When he reviewed Adcom's $800 GFP-565 solid-state preamplifier, the GFP-565, in Stereophile's February 1990 issue, Gary Galo enthused at length over its sound quality. Following comparisons with the Forté 2, Adcom GFP-555 and GTP-400, Hafler DH-110, and even the Audio Research SP11 Mk.II, he concluded that the GFP-565 "is a superb preamplifier that can hold its own with all but the most expensive products"; it "sets the standards for preamps under $1000" and easily deserves a Class B rating in Stereophile's "Recommended Components" listing.…
Sidebar 1: JA's 1990 Review System
Both preamplifiers were substituted into my current reference system: Meridian 208 and Kinergetics KCD-40 CD players; Audio Research Classic 60 power amplifier; Avalon Eclipse loudspeakers, connected to the power amplifier with 5' bi-wired lengths of AudioQuest Clear cable; Audio Research and AudioQuest Lapis interconnects; Linn Sondek/Ekos/Troika LP player. For comparisons with either a Mod Squad Line Drive or a Mark Levinson No.26 preamplifier, levels were matched at 1kHz. The Adcom GFA-555 II amplifier was also used some of the time, connected to the…
Sidebar: Measurements
The Adcom GFP-565 exhibited a flat frequency response measured from the CD input to Norm outputs, as shown in fig.1. RIAA accuracy was also very flat, deviating less than 0.1dB across the audible band (fig.2). Phono overload was a high 110mV at 1kHz. THD and noise, again measured from CD input to Norm out, was less than 0.006% across most of the band, rising slightly above 12kHz (fig.3).—Robert Harley
Fig.1 Adcom GFP-565, line input frequency response, 250mV output level (0.2dB/vertical div.).
Fig.2 Adcom GFP-565, RIAA error (0.5dB/…
Sidebar 2: Specifications
Description: Solid-state stereo preamplifier. Output impedance (bypass, normal, and lab outputs): 100 ohms; Output level: 2.0V (rated), 10.0V (max); THD plus noise: 0.0025% (high-level), 0.009% (phono). IM distortion (SMPTE): 0.0025% (high-level), 0.0025% (phono). Frequency response (±0.5dB): 5Hz–90kHz (high-level), 5Hz–70kHz (phono). RIAA accuracy: 20Hz–20kHz ±0.1dB. Weighted S/N ratio: >100dB (high-level), >95dB (phono). Power consumption (120V AC/50–60Hz): 10W.
Dimensions: 17" W by 12 9/16" D by 3¼" H. Weight: 11 lbs.
Sample tested: SN 935-…
Photo: Claire Stefani
The wondrous drummer Paul Motian died Tuesday morning at the age of 80 (he didn't look much older than 60), and New York, the only city where he ever played for the past decade (and he seemed to be playing somewhere all the time), feels a little emptier.
Motian had a way of juggling rhythm, mood, and compositional structure like nobody else, so insouciant by all appearances yet incredibly disciplined if you listened closely. Often, when I'd see him play at a club, I'd focus on what he was doing, and I couldn't figure it out. At first, it seemed to have no…
Once upon a time, manufacturers and distributors of high-end-audio gear were at least minimally respectful of one another. Yes, there was that whole stupid Linn vs. SOTA thing in the 1980s, fueled primarily by one writer and one editor at one magazine. And, yes, there was a period of time during which the owners of Magnepan and Apogee Acoustics stopped making friendship bracelets for each other. Still, people got along well enough. From time to time one could even hear the smartest designers—Nelson Pass, J.C. Morrison, Denis Morecroft, Bruce Thigpen, and Touraj Moghaddam stand out in my…
With "Don't Cry No Tears," from Neil Young's Zuma (LP, Reprise MS 2242), my system sounded less tonally complex with the Kimber Toniks than with my Shindo cables; with the latter in place, it was easier to hear and to appreciate the distinctions among, say, the different drum-kit sounds in different songs. (On this as on so many Neil Young albums, different tracks were produced by different people; in those produced by David Briggs, including the above, the drum sound is somewhat rawer, while the kick drum in other tracks sounds overdamped and thuddy by comparison.) But with a $80 Kimber…
Sidebar: Contacts
Acoustic Revive, Sekiguchi Machine Sales Co., Ltd., 3016-1 Tsunatori-machi, Isesaki-shi, Gunma Pref. 372-0812, Japan. Tel: (81) 270-24-0878. Fax: (81) 270-21-1963. US distributor: Acoustic Revive USA., Mooresville, NC 28115. Tel: (704) 230-0029. Web: www.acousticreviveusa.com.
Kimber Kable, 2752 South 1900 West, Ogden, UT 84401. Tel: (801) 621-5530. Fax: (801) 627-6980. Web: www.kimber.com.
Nordost Corporation, 200 Homer Avenue, Ashland, MA 01721. Tel: (800) 836-2750, (508) 881-1116. Fax: (508) 881-6444. Web: www.nordost.com.