Audio Research D79B

Name: Audio Research D79B
Brand: Audio Research

A rare tube power amplifier using a quad of 6550 or KT88 output tubes, originally priced at $3000.

Overview

The Audio Research D79B is a tube power amplifier made by Audio Research, a company known for high-end audio equipment. It uses a quad of 6550 tubes and can also operate with KT88 tubes, placing it among vintage high-end separates favored for their warm tube sound. The amplifier has been used in bi-amped setups, including with Snell Type A 2 speakers, and appears in enthusiast lists of notable vintage tube amplifiers. While specific production years and technical performance data are not available, the D79B was recognized as rare as early as 2013.

Specifications

Product type	power amp, tube amplifier
Output tubes	6550 (quad), KT88 (substitutable)
Original price	$3000.00

Design

The D79B is a tube amplifier built around a quad configuration of 6550 tubes, with compatibility for KT88 tubes. A service manual exists for bias adjustment, covering both the D79B and D79C models, indicating a shared or similar internal design approach.

Reception & Use

The D79B has been described as providing "warm tube support," reflecting its sonic character in high-fidelity systems. It has been used to bi-amplify Snell Type A 2 speakers and is listed in vintage high-end tube amplifier collections and enthusiast discussions, affirming its status among sought-after tube amplifiers.

Collectibility

The D79B was originally priced at $3000, a significant investment at the time, and was described as "rare" in a 2013 listing. Its inclusion in curated vintage high-end lists and the existence of a dedicated service manual contribute to its collectible status.