Owner’s Manual Reference 150 Stereo Power Amplifier
Contents Model Reference 150 Stereo Amplifier Illustrations 3 Preface 4 Packaging 4 Accessories 4 Warnings 4 Vacuum Tubes and Preparation for Use 5 Panel Controls 5 Use of Controls 5 Installation 5 Connections 6 – 7 Remote Turn-on Connections 7 Operating Procedure 7 Output Tube Bias Adjustment 8 Cooling Fan Speed Adjustment 8 Hour Meter 8 Servicing 8 Cleaning 9 Disposal and Recycling Guidelines 9 Limited Warranty 9 Specifications 10 2
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Preface Please take time to carefully read and understand the following instructions before you install or attempt to operate this equipment. Becoming familiar with the product and its correct operating procedures will help assure you of maximum musical enjoyment and reliable operation. The effort you invest now will be well rewarded in the years ahead. Packaging Save all packaging accompanying this product.
recommend leaving your Reference 150 ‘on’ 24 hours a day as is the custom of some audiophiles to achieve maximum sonic performance on demand. While this is often recommended for solid-state equipment, Audio Research does not recommend this procedure for vacuum tube power amplifiers. (2,000 hours of tube life will elapse in 84 days!) Installation Vacuum Tubes and Preparation for Use Your Reference 150 amplifier is shipped with the vacuum tubes packed in foam blocks.
Connections Input Connector: The Reference 150 uses a fully balanced circuit topology and has a pair of balanced XLR input connectors on the rear panel. It therefore requires a balanced preamplifier output, as provided by most Audio Research preamplifiers. Connect your preamplifier's output to the Reference 150 before turning on the amplifier. Output Connectors: Proprietary, heavyduty output terminals are provided on the rear panel for 4, 8,or 16-ohm speaker impedance loads.
receptacle. If there is any question regarding proper grounding procedures in your installation, seek help from a qualified technician. Caution should be taken before using custom after-market power cords: they must be at least 12gauge and have a standard grounding plug properly installed. These power cords are to be used with caution, at the sole risk of the owner.
Output Tube Bias Adjustment As shipped from the factory, the output ‘bias’ adjustments are set for a nominal 65mA per KT120 tube. Under these idle conditions the tubes are each dissipating approximately 27 watts of their 60 watt rating. This point of operation provides ‘enriched’ Class AB1, and will satisfy the most critical listener. For best results, operate and adjust the Reference150 at 120VAC.
Cleaning Limited Warranty To maintain the new appearance of this amplifier, occasionally wipe the front panel and top cover with a soft, damp (not wet) cloth to remove dust. A mild, non-alkaline soap solution may be used to remove fingerprints or similar smudges. Cleaners containing abrasives should not be used as they will damage the anodized finish of the front panel. A small, soft paintbrush is effective in removing dust from bevels, the recessed nameplate and other features of the front panel.
Specifications POWER OUTPUT: 150 watts per channel continuous from20Hz to 20kHz. 1kHz total harmonic distortion typically 0.6% at 150 watts, below 0.03% at 1 watt. Approximate actual power available at ‘clipping’ 160 watts (1kHz). (Note that actual power output is dependent upon both line voltage and ‘condition’ i. e.: if power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not very critical.) POWER BANDWIDTH: (-3dB points) 5Hz to 80kHz.
