Audio Research LS-2 Preamplifier

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)