Tube Preamp Reviews

Sidebar 1: Specifications

Description: Fully balanced, tubed line-stage preamplifier with LCD touchscreen, custom-tuned resistor stepped-ladder volume attenuation, and remote. Tube complement: Six 6H30 audio tubes, one 6H30 and one 6550 power supply tube. Inputs: Four pairs XLR (balanced), four pairs RCA (single-ended). Outputs: Two pairs XLR (balanced), one pair XLR Sub; two pairs RCA (single-ended), one pair RCA Sub (buffered to drive low-impedance subwoofer plate amps). Gain: 15dB balanced, 9dB single-ended. Sensitivity: 350mV single-ended and balanced. THD: 0.007% balanced, 0.03% single-ended. S/N ratio: 100dB balanced, 84dB single-ended. Maximum input: 18V balanced, 9V single-ended. Input impedance: 50k ohms balanced, 25k ohms single-ended. Output impedance: 600 ohms balanced, 300 ohms single-ended. Subwoofer output impedance: 200 ohms balanced, 100 ohms single-ended. Frequency response: 1.5Hz–24kHz, –1dB, 120kHz, –3dB. Other connections: Two 12V triggers with independently adjustable delays; remote IR in (unpowered); DB9 RS-232 for integrators; rear USB for firmware update; rear ground lug; 20A IEC receptacle.
Dimensions: 19" (482.6mm) W × 8 1/8" (206.5mm) H × 19 1/16" (484.2mm) D. Weight: 62.5 lb (28.35kg).
Finishes: Natural Silver or black anodized.
Serial numbers of units reviewed: REF20R5 (release candidate), 057068 (production model), 57165 (measured). Designed and built in Maple Grove, MN, USA.
Price: $48,000. Approximate number of US dealers: 40. Warranty: 3 years on product, 90 days on tubes.
Manufacturer: Audio Research, 6655 Wedgwood Rd. N., Suite 115, Maple Grove, MN 55311, USA. Tel: (763) 577-9700. Email: service@audioresearch.com. Web: audioresearch.com.