The Groove Master Phono Preamp
8 Inches round, 2 1/2 inches high
Hand-constructed and 100% tested. Made in USA
v Vinyl playback with supreme transparency of tone and space, and 103dB dynamic range.
v Unique, beautiful, small "stack of records" appearance. v From the quietest musical passages - to the most powerful dynamic crescendos –music is reproduced with purest fidelity available from any phono preamp
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Comparison |
GM Phono Preamp |
Sutherland PhD |
|
Cost |
$1900 |
$3000 |
|
SNR, unwtd |
90dB, MM |
63dB, MM |
|
|
70dB, MC |
29dB, MC (!) |
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SNR, “A” |
99dB, MM |
91dB, MM |
|
|
79dB, MC |
53dB, MC |
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RIAA error |
+ - 1dB |
+ - 0.3, 0.1dB |
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THD |
0.002% |
0.0086% |
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1kHz headroom |
19.1dB |
18.7dB |
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20kHz headroom |
36.4dB |
8.7dB |
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DC offset |
NONE |
17.5mV |
Specs:
I originally designed this not to market, but because I wanted a no-compromise phono preamp. I used the recently-introduced LSK 389 ultra-low noise discrete JFET ( junction field-effect transistor) for the all-important input stage. This provides the ultra-pure musical transparency of a single-ended triode (SET) tube, but (unlike the tube) this JFET has state-of-the-art low noise.
The JFET is combined with the Analog Devices AD797, one of the world's purest audio amplified devices,in a patent-applied-for configuration that delivers ultra-low distortion performance, both measured and (most important) sonically.
The overall circuit design has been thoroughly tested and confirmed to be immune to AC power line noise and radio frequency interference (RFI). Thus, expensive power line conditioners and exotic interconnect cable are not needed. The Groove Master's low output impedance
( 1 K ohm) can drive up to 30 feet of cable to your power amplifier without audible signal degradation. This preamp has extremely high musical fidelity, possibly unsurpassed at any price.
State of the art Analog Devices AD797 amplifiers. Considered by audiophiles and engineers to be one of the most sonically transparent amplifying devices available.
External AC line powered DC supply. This ensures complete absence of power line hum. It is actually quieter than a well-known $3K battery-operated phono preamp.
Conformance to the standard RIAA
playback frequency response curve is within ± 0.2 dB from 40 Hz to beyond 20 KHz. Response at 20 Hz is down by only 0.4 dB, as part of the preamp’s infrasonic rolloff, which attenuates low frequency vibration from warped records, etc.
Very high headroom: 19 dB at 1 KHz, 36 dB at 20 KHz. This prevents the preamp from ever overloading even on the highest recorded transient peaks. Note: to ensure this, the Gain Select Switch must be set appropriately from your cartridge. The lowest gain selection (that can drive your audio amplifier to full power) is advisable, since the Groove Master can supply undistorted peaks exceeding 7 volts ( if the gain is too high).
Additional Features:
• Accomodates moving magnet (MM) and moving coil (MC) cartridges.
• 6 position each: loading capacitance loading resistance, and gain switches, conveniently located on front panel ( no cumberson jumpers or tiny DIP switches)
• 36 to 70 dB gain range ( at the standard 1 KHz)
• Stereo/Mono and Mute switches
• Attractive cylindrical enclosure is completely sealed to electromagnetic interference (EMI).
• Ultra-high quality components, including round PC board that provides short, direct audio signal paths. PC board is acoustically damped with absorbent pads; the Groove Master is insensitive to even strong sound field vibrations.
• The Groove Master is powered by an external wall AC supply, but is quieter than many battery-powered preamps.
• With a high-output MC cartridge, the dynamic range is 103 dB, which is 7 dB greater than the max. available CD.
• Intrinsic Fidelity Test: The Groove Master was preceded by a stereo pair of Inverse RIAA networks ( duplicating the standard LP recording curve), and fed audiphile-quality SACD music. An ultra-high quality A/B switch with 0.05 dB level matching (desicribed in Audio Xpress, June ‘07) was used to compare the direct music source with the Groom Master output.
• The Groove Master is completely faithful to the music on your vinyl, limited only to the cartridge, power amps, and speakers.