Audio Research LS28SE Line-Stage Preamplifier

The LS28SE is a high-end preamplifier that combines technical excellence with an emotional, lifelike connection to music. Drawing from innovations in Audio Research’s Reference 160-series amplifiers, it features upgraded components that enhance clarity, resolution, dynamics, and spatial detail. Its natural balance and smooth, relaxed sound encourage long listening sessions. Often overlooked in audio systems, the preamplifier plays a critical role, and the LS28SE elevates performance with organic tone and refined detail. It brings new vitality and realism to systems, unlocking musical nuances that lesser preamps fail to reveal.

Frequency Response: +0-3dB, 0.4Hz to 200kHz at rated output
(Balanced, 200k ohms load)

THD+Noise: Less than .007% at 2V RMS BAL output

Noise: Less than -100dBv at max volume (103)

Dynamic Range: 122dB (AES17)

Crosstalk: -105dB

Gain: Main output: 18.5dB balanced output.
(12.5dB SE output.)  Record output: 0dB (Processor input: 0dB balanced out).

Input Impedance: 100K ohms Balanced, 50K ohms SE.
8 Inputs – 4 balanced, 4 single-ended.

Output Impedance: 600 ohms Balanced, 300 ohms SE Main (2), 20K ohms minimum load and 2000pF maximum capacitance. Outputs (3): 2 Main, 1 Record (XLR and RCA connectors).

Output Polarity: Non-inverting

Maximum Input: 16V RMS BAL, 8V RMS SE

Rated Outputs: 2V RMS (1V RMS SE) into 200K ohm balanced load (maximum balanced output capability is 17V RMS at less than 0.5% THD at 1kHz).

Controls: Rotary volume selector (103 steps) and rotary input selector. Push buttons: Power, Menu, Enter, Mono, Invert, Mute.

Power Supplies: Electronically regulated low and high voltage supplies.  Automatic 45 sec. warm-up/brown-out mute.  Line regulation better than .01%.

Tube Compliment: (4) 6H30P dual triode

Power Requirements: 105-125VAC 60Hz (200-250VAC 50/60Hz) 130 watts maximum

Standby: 2W

Dimensions:

Width: 19” (48 cm) 

Height: 6.5” (13.7 cm) 

Depth: 13.7” (34.8 cm)

Handles extend 1.6” (4 cm) forward of the front panel

Weight:   16.0 lbs. (7.2 kg) Net; 24 lbs. (10.9 kg) Shipping