The Grason-Stadler 162K is a specially modified McIntosh MC-40 amplifier that was designed to be used as a studio monitor in conjunction with the Grason-Stadler 162 "Speech Audiometer" speech and hearing analyzer.  Electronically the Grason-Stadler amplifier is the same as the McIntosh amplifier with the addition of a VU meter connection, VU meter adjustment control, and an attenuate circuit between the input and first 12AX7 preamplifier tube.  The amplifier pictured above is one of a matched pair of mint GSC amplifiers I have in my collection.  The output 6L6GC tubes that I use on these amps are 1996 Svetlana brand tubes made by the Svetlana Electron Devices Inc. Russia.

Tube Line Up:
12AX7...Preamplifier
12AU7...Preamplifier
12BH7...Preamplifier
12AX7...Preamplifier
6L6GC x 2...Push Pull Audio Output
Solid State Rectifiers

Measurements:
Height...7-7/8 inches
Width...8-1/8 inches
Depth...13-3/4 inches

    Learn more about the McIntosh MC40 by visiting Roger Russell's McIntosh History Page web site by clicking on the link below.

Roger Russell's McIntosh History Page

Grason-Stadler's corporate website

    Instruction Manual for the Grason-Stadler Speech Audiometer Model 162.  The schematics and instructions to use the 162K amplifier is included.

    This is a picture of the Grason-Stadler Speech Audiometer Model 162.  It was designed for speech and hearing analyses and has it's own built in amplifier using 6V6 push-pull output tubes.  The 162K amplifier was designed to give an added boost in amplification when required by the user.

    This is a comparison of the two input circuits showing the difference between the Grason-Stadler 162K (left) and that of the McIntosh MC40 (right).  The circuit for the Grason-Stadler 162K allows less audio input signal then does the circuit for the McIntosh MC40 but it can easily by rewired to match McIntosh's input circuit.