Audio Research LS28SE Line Stage
Audio Research LS28SE Line Stage
Audio Research LS28SE Line Stage
Audio Research

LS28SE Line Stage

At the heart of the LS28SE are four 6H30 vacuum tubes in the analogue circuit. While the LS28SE is the perfect match for any Audio Research amplifier, it has been designed to work with nearly any amplifier on the market today.

3 Years


The LS28SE line stage is a flexible and intuitive preamplifier. Four balanced and four single-ended inputs, and two sets of both balanced and single-ended outputs, allow maximum connectivity. The straightforward menu allows control of numerous parameters, including input naming, tube hours, auto shutdown, and home theatre passthrough. Phase invert and mono are also standard functions.

The improvements in the LS28SE stem from what was learned during the creation of Audio Research’s Reference 160-series amplifiers. Very similar to the wire and parts changes incorporated in the REF6SE and REF PH3SE, the LS28SE also includes upgrading to the same proprietary gold coupling caps used in the REF6SE. These numerous and costly component upgrades elevate the LS28SE’s performance to an entirely new level. The improved clarity, resolution, transient snap, sense of space, and a relaxed purity are instantly noticeable and will inspire extended listening sessions.

Since 1970, High Definition has been more than a trademark; it has been our guiding principle for all products. The Foundation Series continues this passion and philosophy, offering the listener stunning playback, great value, and unparalleled long-term support.

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.


Less than -100dBv at max volume (103).

Dynamic Range

122dB (AES17).




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


Maximum Input


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).


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 Complement

(4) 6H30P dual triode.

Power Requirements

105-125VAC 60Hz (200-250VAC 50/60Hz) 130 watts maximum.




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.