Note
The GD-125 is mostly a repackaged QF-1. Its 2-tone gray paint distinguishes it from SB series accessories like the HD-15 that were packaged in the same box. The GD-125 was designed for use with Heath general coverage receivers including the GR-64 and other receivers with IFs from 450-500 kHz. Note that the 125 cannot be used with the GR-54 because of that receiver’s incompatible IF. The GD-125 is designed to improve the selectivity of inexpensive receivers and works very well. It has an effective Q of 4000 and provides a notch for adjacent signal rejection.
Caution: If connected to an AC-DC receiver, the chassis and cover of the Q-multiplier may be at mains potential.
Operating frequency: 450-500 kHz
Power requirements: 120/240 VAC, 50/60 Hz, 4.5 watts
Tubes: (1) 12AX7
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
