Audio Research LS-2 Preamplifier

Pure-Tube, Zero-Feedback Class-A Design With 6H30 Tubes and a Full Touchscreen Interface

Inspired by the original LS2 line stage introduced in 1992, the Audio Research LS-2 brings the company’s tube preamplifier tradition into a thoroughly modern platform. Its signal path is pure tube, with no solid-state devices, using two 6H30 dual-triode tubes in a single gain stage operating in pure class-A with zero feedback.

The LS-2 employs a cathode-follower design and constant-current cathode bias, combining a deliberately simple signal path with the current capability of the 6H30. Audio Research describes the result as having clarity, finesse, harmonic richness, dynamic swing, and a natural resolution of detail.

A Modern Audio Research Interface

The LS-2 pairs its traditional tube circuitry with an all-new touchscreen interface. The display provides balance control, input naming, adjustable intensity, color selection, and additional operating functions, with typography derived from the Reference-series GhostMeters. A new machined-metal remote provides control from the listening position.

Flexible Analog With Optional Digital and Phono

Balanced XLR and single-ended RCA connections accommodate a range of source components. For systems requiring additional functionality, the LS-2 can be expanded with a user-installable DAC card providing USB, coaxial, and optical inputs. A separate user-installable MM/MC phonostage card provides 42 dB of gain for moving-magnet cartridges and 62 dB for moving-coil cartridges. Both cards are optional.

Features

• Pure-tube signal path with two 6H30 tubes
• Single gain stage operating in pure class-A
• Zero-feedback circuit design
• Cathode-follower topology with constant-current cathode bias
• Balanced XLR and single-ended RCA inputs
• Full touchscreen interface with balance control and input naming
• Adjustable display intensity and color
• Machined-metal remote control
• Optional user-installable DAC card with USB, coaxial, and optical inputs
• Optional user-installable MM/MC phonostage card with 42 dB/62 dB gain

Specifications

Frequency Response (At Rated Output, Balanced, 100 kOhms Load): -0.3 dB at 10 Hz, -0.3 dB at 40 kHz

THD + Noise (2 V RMS Balanced Output, 10 Hz–80 kHz, Unweighted): <0.03%

Noise (Maximum Volume, 99): -77 dBV

Crosstalk: -76 dB

Gain: 12 dB balanced output, 12 dB single-ended output

Input Impedance: 25 kOhms balanced and single-ended

Output Impedance: 10 ohms balanced, 225 ohms single-ended

Output Polarity: Inverting, balanced and single-ended

Power Requirements: 120 VAC, 60 Hz, 35 W maximum

Standby Power: 120 VAC, 60 Hz, 4.4 W

Tubes Required: 2 x 6H30

Dimensions (H × W × D): 7" x 19" x 17.5" (177.8 x 482.6 x 444.5 mm)

Weight: 33 lb. (15 kg)