Audio Research D79B
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 from Audio Research, a company known for high-end audio equipment. It uses a quad of 6550 tubes and can also run with KT88 tubes. It sits among the vintage high-end separates favored for their warm tube sound. People have used it in bi-amped setups, including with Snell Type A 2 speakers, and it shows up in enthusiast lists of notable vintage tube amplifiers. Production years and technical performance data are not available. The D79B was already being called rare in 2013.
Specifications
| Product type | power amp, tube amplifier |
| Output tubes | 6550 (quad), KT88 (substitutable) |
| Original price | $3000.00 |
Design
The D79B is built around a quad of 6550 tubes, and it takes KT88 tubes too. A service manual covers bias adjustment for both the D79B and the D79C. That suggests the two models share a similar internal design.
Reception & Use
The D79B has been described as providing "warm tube support." It has been used to bi-amplify Snell Type A 2 speakers, and it appears in vintage high-end tube amplifier collections and enthusiast discussions.
Collectibility
The D79B was originally priced at $3000, a significant sum at the time. A 2013 listing described it as "rare." It also has its own service manual, and it turns up in vintage high-end lists.
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