Audio Research LS-28

This Audio Research LS-28 line stage pre-amplifier is a store demo and is in excellent physical and working condition. All accessories including the original box and remote control are included with the sale. Because these are store demos they still retain Audio Research's full manufacturers warranty. 

The LS-28 has less than 1000 hours on the tubes and is nearly flawless with no scratches, dents or dings. The remote has never been use and is still wrapped in its packaging.

The pre-amp will be well packed and shipped fully insured within one business day. It is guaranteed to arrive in the condition described. 

The LS28 line stage is a flexible and intuitive pre-amplifier. 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 theater pass-through. Phase invert and mono are also standard functions. At the heart of the LS28 are four 6H30 vacuum tubes in the analog circuit. While the LS28 is the perfect match for any Audio Research amplifier, it has been designed to work with nearly any amplifier on the market today.

Since 1970, High Definition has been more than our 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.

Preliminary Specifications

• Frequency Response: +0-3dB, 0.2Hz to 160kHz at rated output (Balanced, 200k ohms load)
• Distortion: Less than .01% at 2V RMS BAL output
• Gain: Main output: 18dB balanced output. (12dB SE output.) Record output: 0dB (Processor input: 0dB balanced)
• Input Impedance: 120K ohms Balanced, 60K ohms SE. 8 Inputs – 4 balanced, 4 single-ended
• Output Impedance: 700 ohms Balanced, 350 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: Low Gain: 48V RMS BAL, 24V RMS SE, Medium Gain: 24V RMS BAL, 12V RMS SE, High Gain: 12V RMS BAL, 6V RMS SE
• Rated Outputs: 2V RMS 1Hz to 100kHz into 200K ohm balanced load (maxi- mum balanced output capability is 15V RMS at less than 0.5% THD at 1kHz)
• Controls: Rotary volume selector (104 steps) and rotary input selector
• Push buttons: Power, Menu, Enter, Mono, Invert, Mute
• Power Supplies: Electronically regulated low and high voltage supplies. Automatic 50 sec. warm-up/brown-out mute. Line regulation better than .01%
• Noise: 1.3uV RMS residual IHF weighted balanced equivalent input noise with volume at 1 (100dB below 2V RMS output)
• Tube Complement: (4) 6H30P dual triode, (Hybrid JFET/ tube audio circuit, solid-state power supply)
• Power Requirements: 105-130VAC 60Hz (210-260VAC 50/60Hz) 50 watts maximum.