Dynaco PAS-4 Vacuum Tube Preamplifier
Dynaco Stereo 80  Vacuum Tube Power Amplifier
Dynaco Stereo 160 Vacuum Tube Power Amplifier

Dynaco Owner's
Manuals - with
Schematics -
in Acrobat format.

Stereo 80
Power Amplifier
Goldpoint Selector Switches
Stereo 160
Power Amplifier
Passive Preamps - Precision Level Controls

With production starting in 1959, by the late 1960s hundreds of thousands of Dynaco Stereo 70 power amplifiers were in use world-wide, more than any other stereo power amplifier. And in the 1990s, about 25 years after their heyday, there were still many thousands in use internationally.
In the early 1990s there was a resurgence of interest in "vacuum tube audio" as evidenced by the growing number of newly designed vacuum tube based audio products appearing in trade magazines and showing up at trade shows around the world. 
In 1991 the Dynaco company had been purchased by the Panor Corporation of Hauppauge New York, and in 1993 the Stereo 70 design was updated, becoming the new Stereo 80 (vacuum tube version). 
The Dynaco Stereo 70 
Vacuum Tube Amplifier

The original Stereo 70 amplifier used EL34 output tubes and put out about 35 watts per channel. The updated vacuum tube version Stereo 80 also used EL34 output tubes, supplying about 40 watts per channel. 
Additionally, shortly after the release of the updated vacuum tube Stereo 80, there became available the Stereo 160 power amplifier, which used 6550 type output tubes, supplying about 75 watts per channel. It was, however, built on the exact same size chassis as the vacuum tube Stereo 80, and so looked very similar to it.
The magazine ad from 1994 (below) introduces the modernized vacuum tube Dynaco Stereo 80 - and the upgrade to the PAS-3 preamplifier, the modernized PAS-4 vacuum tube preamplifier. 
Note: There also existed the Dynaco
Stereo 80 Solid State Power Amplifier
The task of updating the circuitry for the vacuum tube Stereo 80, Stereo 160, and PAS-4 was accomplished by John Nunes in San Jose, California. The PC board designs were done by Arn Roatcap in Sunnyvale, California. The factory assembly of these three products was done for Dynaco by TIBI Electronics in Los Angeles.

Dynaco Stereo 160 showing 6550 output tubes.
The Stereo 80 and Stereo 160 were available with either black or chrome front panels.