Sidebar 3: Measurements
I preconditioned the Sonic Impact Super T amplifier with both channels running at one-third maximum output power for an hour into 8 ohms, but, as expected with an amplifier with a high-efficiency switching output stage, the chassis was as cold at the end of that period as it had been at the start. The THD+noise percentage was 0.0911% at the start and 0.0916% at the end; ie, no significant change. The maximum voltage gain into 8 ohms was a little lower than usual, at 25.1dB, and the amplifier inverted signal polarity.
The input impedance depended both on…
As you read this, are you listening to your stereo? Whatever the music, what you're actually hearing is your public utility's AC as modulated by your power amplifier. No matter how good the gear, the final result can be only as pure as the power feeding your components. Unfortunately, plenty of sonic schmutz usually comes along for the ride.
The purveyors of line conditioners, power regenerators, isolation transformers, and the like have been bombarding us with that message for years now, and it seems to have taken hold. Though the message comes larded with multiple helpings of…
In terms of operation, the ASR Emitter II Exclusive proved to be a thoroughly modern product that was convenient to use.
Deep sound
Your New York–based Stereophile flight crew was invited to hear a pair of Emitter II Exclusives in action at Lyric HiFi recently, driving the four-tower Nola Grand Reference loudspeaker system. In-store demos are notoriously tricky, unpredictable, and often unsatisfactory, but usually the experienced listener can come away with at least a general sense of a product's quality. Lyric's combo of Nolas and Emitter II Exclusives was bass-heavy, and produced…
Lovers of Italian wine, travelers to Italy, and, of course, Italians, may be familiar with this story. It seems that in the year 1111, Henry V was traveling to Rome to be crowned Holy Roman Emperor. A member of his entourage, one Giovanni Defuc, was very fond of wine, and had the practice of sending ahead one of his servants to sample the wine in each place. When the servant found a wine that he particularly liked, he would write "Est!" on the door of the establishment, which was a signal to his master that the wine is (est) good. Having arrived at Montefiascone, the servant found a wine he…
Although PS Audio insists that the GCC-100 is not an integrated amplifier, it has an Auxiliary line-level output—just like an integrated. The Auxiliary output can be used to drive another power amp, connecting the speaker cables to that amp rather than to the GCC-100, in which case the GCC-100 functions essentially as a line-level preamp. (Leaving the output/amp section of the GCC-100 without a speaker load is apparently not a problem.) I used this connection to compare the GCC-100's output/amplifier section with two other amplifiers I had on hand.
Comparisons: HCA-2
PS Audio's HCA-…
Sidebar 1: Specifications
Description: Solid-state, variable-gain, integrated amplifier with class-D output stage. Maximum output power: 100Wpc into 8 ohms (20dBW), 200Wpc into 4 ohms (20dBW). Frequency response: 10Hz–20kHz, ±0.1dB. THD: <0.02% at 1W, <0.03% at 100W. Input sensitivity: 1.25V. Input impedance: 47.5k ohms. Adjustable gain: 31–41dB (RCA), 37–47dB (XLR). Power consumption at idle: <40W.
Dimensions: 17.25" (440mm) W by 4" (100mm) H by 14" (360mm) D. Weight: 26 lbs (11.8kg).
Serial Number Of Unit Reviewed: A1-5A025 (auditioning), OC-A7-5F002 (measuring).
…
Sidebar 2: Associated Equipment
Analog Source: Fully updated Linn LP12 turntable, Linn Ittok tonearm, AudioQuest AQ-7000nsx cartridge.
Digital Source: PS Audio Lambda II CD transport; Perpetual Technologies P-1A, ModWright P-3A digital processors.
Preamplification: PS Audio GCPH phono preamplifier.
Power Amplifiers: Audiopax 88SE monoblocks, PS Audio HCA-2.
Loudspeakers: Avantgarde Acoustic Uno 3.0, Paradigm Reference Studio/100 v.3.
Cables: Digital: Mystic Reference I2S, Illuminati Orchid AES/EBU. Interconnect: Nordost Quattro Fils, Nordost Valhalla, AudioQuest Sky, PS…
Sidebar 3: Measurements
As set up, the sample of the PS Audio GCC-100 I was sent for measurement had a maximum gain of 42dB into 8 ohms for both balanced and unbalanced input signals. Both inputs were noninverting (ie, preserved absolute polarity), the XLR jacks apparently wired with pin 2 hot. The unbalanced input impedance was a high 50k ohms over most of the audioband, dropping slightly but inconsequentially to 32k ohms at 20kHz. The balanced input impedance was 100k ohms across the band.
The output impedance was a moderately low 0.15 ohm at low and midrange frequencies.…
I haven't been shy in these pages regarding my love for the Mission 731i loudspeaker (reviewed in November 1996, Vol.19 No.11). It quickly became my reference standard for an entry-level audiophile speaker. Subsequent to my review, Mission significantly improved the speaker by introducing a silk-dome tweeter (see Follow-Up in April 1998, Vol.12 No.4). I bought three pairs: one for my home recording studio, one for my faux outdoor summer-home system (guest bedroom windowsills, pointing outward), and one for portable use to drag to friends' parties when their sound systems are not up to snuff…
The m71 deviated from tonal neutrality only in the lower high frequencies. A slight highlighting of this range manifested itself in different ways, depending on the recording. On the Ian recording, her voice was a bit more sibilant than I'm used to, and the electric guitar had a bit more bite. On Kohjiba's The Transmigration of the Soul, from Stereophile's Festival CD (Stereophile STPH007-2), the marimba seemed natural but a bit more prominent in the mix than I've heard through other speakers. On some recordings, the highlighted upper frequencies actually enhanced my enjoyment of the work—…
