Description: headphone amplifier with HeadRoom Audio Image Processor. Output power rating: 1500mW (8 ohm load). Frequency range: DC–100kHz. THD: 0.004%. S/N ratio: >100dB. Maximum input voltage: 3.7V. Maximum output voltage: 6.5V. Maximum voltage gain: 8.8dB. Power supply (Power Station One): ±12V, 800mA (external).
Dimensions: 5.5" W by 4" W by 1.5" H.
Serial number of unit tested: none.
Price: $259 (with Power Station One); Power Station Three adds $259 (1996); no longer available (2006). Approximate number of dealers: 150.
Manufacturer: Audio…
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Sidebar 1: Specifications
Sidebar 2: System
My primary source was the Audio Research CD1 CD player; Kimber Kable KCAG connected the source to the headphone amps. Everything rested upon DH Cones and was plugged into an API Power Wedge 112. I used several pairs of headsets for comparison, including the Grado SR80 and SR125, Sennheiser HD-580 and '580 Jubilee.
While I listened to a wide range of music during the audition period, I'm going to focus my comments on two songs: "Rasd al-dhil Bashraf Sammai," from this month's "Recording of the Month," by the Eduardo Paniagua group, and "Third Uncle," from Brian…
Sidebar 3: Measurements
All of the following measurements were made from the front-panel headphone output. The polarity of the Audio Alchemy v1.0 was noninverting. Its input impedance was 88.2k ohms, its output impedance 0.27 to 0.29 ohms, depending on frequency. S/N measured an excellent 105dB (22Hz–22kHz, unweighted, ref. 1V). DC offset measured 12.5mV in the left channel, 11.5mV in the right. The tracking of the Audio Alchemy's volume control was reasonably good, with a maximum left/right deviation of 0.5dB at half rotation and less. Maximum voltage gain was 8.9dB.
The Audio…
It's hard to know what to call the SHA-Gold. It is a superb headphone amplifier—maybe even the target all future headphone amps need to shoot at—but it's also a full-function preamplifier. At two grand, it's not exactly a unit you'd add to your current system just to get a headphone connection...Wait a minute! What am I saying? I'm sure that there are folks out there who would add this to their existing reference systems as casually as I'd buy the Audio Alchemy headphone amplifier—but they'd be missing out on a great line stage.
I could be wrong about the target audience for the…
Sidebar 1: Specifications
Description: vacuum-tube line/headphone amplifier. Tube complement: two 6DJ8s. Inputs: six line; one tape-loop. Outputs: one single-ended, amplified; one single-ended, passive; one balanced XLR. Maximum voltage gain: 18dB, single-ended; 24dB, balanced. Absolute polarity: non-inverting. Frequency response: 15Hz–200kHz –1dB. Input impedance: 52k ohms. Output impedance: 15 ohms, line; 0.5 ohm, Ç" stereo phone jack.
Dimensions: 19" W by 17" D by 3.5" H. Shipping weight: 21 lbs.
Serial number of unit tested: 51207233SHAG.
Price: $1995 (1996); no longer…
Sidebar 2: System
My primary source was the Audio Research CD1 CD player; Kimber Kable KCAG connected the source to the headphone amps. Everything rested upon DH Cones and was plugged into an API Power Wedge 112. I used several pairs of headsets for comparison, including the Grado SR80 and SR125, Sennheiser HD-580 and '580 Jubilee.
While I listened to a wide range of music during the audition period, I'm going to focus my comments on two songs: "Rasd al-dhil Bashraf Sammai," from this month's "Recording of the Month," by the Eduardo Paniagua group, and "Third Uncle," from Brian…
Sidebar 3: Measurements
The Melos's measurements presented here were taken from the front-panel headphone jack unless otherwise stated—since the SHA-Gold was reviewed primarily as a headphone amp. Selected measurements, however, were also made from the back-panel preamp outputs.
The Melos was non-inverting, both from its headphone jack and its main outputs. (Using its balanced output, pin 2 was wired to be positive, pin 3 negative.) Its input impedance was 82k ohms. Its output impedance was 0.53 ohms at the headphone jack, 21 ohms from output 2.
The S/N ratio measured…
For many years I have used three sets of headphones, all from Grado Laboratories: the Reference RS-1 ($695), the SR-125 ($125), and the SR-60 ($60). I've always favored Grado headphones because the minimal-resonance design philosophy that I feel is responsible for the uncolored midrange of their moving-iron cartridges extends throughout their headphone range as well. Recently, however, I've achieved a new perspective regarding the SR-125 'phones that I felt would be of interest to Stereophile readers.
I've recently constructed a system, based on my Dell Windows PC, for recording…
Sidebar: Specifications
Description: Dynamic open-air headphones. Frequency range: 20Hz–20kHz. Sensitivity: 98dB SPL for 1mV input. Nominal impedance: 32 ohms.
Serial number of unit reviewed: None.
Price: $150/pair. Approximate number of dealers: 500.
Manufacturer: Grado Laboratories, 4612 Seventh Avenue, Brooklyn, NY 11220. Tel: (718) 435-5340. Fax: (718) 633-6941. Web: www.GradoLabs.com.
The Ortofon MC-2000 may just have been the most impractical cartridge to be unleashed upon the audio community for some years. With a high compliance (20cu) that made it ill-suited for most tonearms, it also had a preposterously low signal output of 50 microvolts, which gave new meaning to the terms hum and noise. Few MC preamps had enough gain to deliver adequate driving voltage to a system, and none of those that did had low enough noise to be usable with the 2000. If the problem wasn't hum, it was hiss; if hiss was acceptably low, there would be too much hum. At least Ortofon had the sense…