Audio Research is one of the most dependable brand names when it comes to high-end audio systems. For years the brand has been recognized by audiophiles throughout the world as equipment that delivers clear and consistent quality in music.

What are the specs for the Audio Research LS25?

Frequency Response:
±.5dB, 1.0Hz to 100kHz -3dB pionts below 0.2Hz and 400kHz
Distortion:
Less than .01% at 2V RMS output
Noise & Hum:
14µV RMS residual IHF weighted balanced noise output with gain control at minimum (103dB below 2V RMS output).
Gain:
Main Output: Selectable for each input: 18db, 12dB, 6dB Balanced output. (12dB, 6dB, 0dB SE output). Record output: 0dB.
Input Impedance:
120K ohms Balanced, 60K ohms SE.
Output Impedance:
650 ohms Balanced, 325 ohms SE Main (2), 20K ohms minimum load and 2000pF maximum capacitance.
Maximum Inputs:
28V maximum, BAL, 14V maximum SE (6dB gain)
Rated Outputs:
2V RMS 1Hz to 100kHz into 200K ohm balanced load (maximum balanced output capability is 40V RMS at less than 0.5% THD at 1kHz).
Power Supplies:
Electronically-regulated low and high voltage supplies. Automatic 40 sec. warm-up/brown-out mute. Line regulation better than .01%.
Tube Complement:
LS25: (4) 6922/E88CC. LS25 MKII: (2) 6H30 .
Power Requirements:
100-135VAC 60Hz (200-270VAC 50/60Hz) 45 watts maximum
Other:
Vacuum tube audio circuit, solid-state power supply. Inputs (8): Tuner, Phono, CD, Video, Aux 1, Aux 2, Monitor, Processor (XLR and RCA connectors). Outputs (3: 2 Main, 1 Record (XLR and RCA connectors). Controls: Volume (104 steps), Gain, Balance, Input. Toggle switches: Power On/Off, Stereo/Mono, Bal In/SE In, Processor/Input, Monitor/Input, Mute/Operate.
Dimensions:
19" (48 cm) W x 5 ¼" (13.4 cm) H (standard rack panel) x 11 ¾" (29.8 cm) D Handles extend 1½" (3.8 cm) forward of front panel.
Weight:
18 lbs. (8.2 kg) Net; 28 lbs. (12.7 kg) Shipping.

What else to know about the Audio Research LS25?

The LS25 vacuum tube stereo line preamplifier offers sonic performance, functional flexibility and value second only to the world-renowned Reference One preamplifier. It is unprecedented measured by any performance criteria at its price. Many will perceive the LS25 as a more compact REF1 -- and to be sure, there are many similarities in the mechanical design. Chassis construction is like the REF1, with finished slab sides and heavy top and bottom covers; chassis height and depth are slightly reduced, however. Front-panel control layout is also familiar: microprocessor-controlled rotary devices are used for overall gain set (High, Medium and Low), volume, balance and input selection. Two-way toggle switches control Power On / Off, Stereo / Mono, BAL / SE, Processor / Input, Monitor / Input and Mute. The selectable overall gain function allows a wider range of volume-control operation for input sources having different output levels (for example: a phono stage vs. a high-output D/A converter). The A-V processor to control overall system volume level instead of the LS25's volume control when used in this mode. Thus, the LS25 fits smoothly into any high-performance installation which combines audio and video playback functions. The rear panel offers a full complement of audiophile-grade balanced and single-ended connectors: seven inputs (including tape monitor), a tape / record out and two sets of main outputs. Balanced or single-ended optimization for every input is selected via the front-panel toggle, and is automatically remembered (along with previously selected gain level) by the LS25’s internal memory. All functions (except gain and SE / BAL) are addressable via the supplied handheld IR remote control. A.C. power is supplied at the rear panel via a three-pin IEC socket and 14-gauge detachable power cord. Inside, the LS25 is pure Class-A operation Audio Research: gain is supplied via four 6922 twin triodes, with fully regulated massive power supplies and Infinicap coupling caps at the output for maximum dynamics and transparency. Performance is smooth and detailed, with good soundstage focus and plenty of deep bass impact. The overall presentation is refined, yet with power that extends effortlessly into the frequency extremes. Like the REF1, the LS25 never meets a sonic challenge it can’t handle with aplomb -- and it does so while offering all the features needed to fit into today’s multipurpose entertainment systems. \[From the ARC website]

Brief History of Audio Research

Other Audio Research Products We Often Buy

Typically, StereoBuyers purchases mostly used amplifiers, especially the vintage amps and high-end Audio Research models.

StereoBuyers has purchased tens of thousands worth Audio Research brand equipment since 2014, with individual buys ranging from $100 to well over $50,000. If you are moving, ready to upgrade, or have Audio Research equipment you do not or will not be using, why not contact us today to find out if it is worth good money?

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The following images show actual Audio Research equipment purchased by StereoBuyers.