INPUT: Matches all known magnetic pickup cartridges, both moving coil and moving magnet. (The cartridge load resistance can be set for each channel to 47 kohms, 470, 200, 100 or 20 ohms with two internal switches.)
GAIN: Zero to 52, 60, 70 or 80 dB at 30 to 35 Hz using the single-turn audio taper gain control. (The maximum gain for each channel is set with two internal switches.)
RESPONSE: Playback RIAA as shown in Figure 1. (Max gain can be set to 52, 60, 70 or 80 dB.) The rumble filters, which may be switched in and out, have corner frequencies of 20 Hz and change the response as shown. Because the preamp was designed to drive a sound card, it includes lowpass filters with corner frequencies of 25 kHz. This causes no loss of quality because the CD sampling rate of 44.1 kHz limits the unaliased frequency response to 22 kHz.
Fig. 1 -- Playback RIAA response. Max gain can be set to 52, 60, 70 or 80 dB.
DYNAMIC RANGE: Figure 2 is a spectrogram of a typical channel with the gain set to 52 dB and the gain control at max. (47 kohm load resistance). Dynamic range is over 90 dB. Figure 3 is a spectogram of a typical channel set to 80 dB and the gain control at max. (200 ohm load resistance). Dynamic range is nearly 80 dB. Actual dynamic range will depend on the output noise and hum of your turntable.
Fig. 2 -- Typical output spectrum at 52 dB max gain with volume set to max.
Fig. 3 -- Typical output spectrum at 80 dB max gain with volume set to max.
CONNECTORS: Two female, panel mount RCA input connectors. Two female, panel mount RCA connectors plus a 1/4 inch stereo phone jack for output. There is a 5-way binding post near the input connectors for connecting the preamp enclosure to the turntable frame as this may help reduce hum pickup (see the Operation section in the User Guide for more information on hum reduction). 2.5 mm male input connector for the 24 VDC power supply. A green LED lights when the charging voltage is on and a red LED lights when the preamp is operated from the power mains.
POWER: Two internal 9 volt rechargeable NiCd or NiMH batteries provide about 3 hours of operation from a full charge. The 24 VDC power supply plugs into any (US) standard 115 VAC, 60 Hz outlet. (Power supplies for other mains voltages and outlets available on special order.) The charger can be left on to trickle charge the batteries all the time the preamp is not in use. In addition, the batteries are on charge while the preamp is operating from mains power (both the green and red LEDs are lighted).
FURNISHED: 24 VDC wall power supply, Printed User Guide
PHYSICAL: Rack mount enclosure (1RU7) measuring 19 x 9 x 1-7/8 inches overall including connectors and knobs. Weight is 2 kgm (about 4.4 pounds) with batteries installed. Stick-on rubber bumpers for the four corners of the enclosure bottom are supplied for non-rack mount installation.
PRICE: See price list. PRICES
