Webster Model 79 & 80 Wire Recorder EQ Curves for flat transfer

[Craig Maier]

Recently, I had been asked to provide EQ curves for use with flat transfers of recordings made on the Webster Model 79 & 80 wire recorder(s). The Webster was a tube-based wire recorder used circa 1945. I looked at the circuit diagram and noted that it included a fixed pre-emphasis network for recording. However, it had no fixed de-emphasis network for playback; it appears that it relies on the tone control to reverse the recording pre-emphasis (coupled with the users taste). So, I SPICE modeled the main playback amplifier circuit, including the tone control. I analyzed 4 positions of the Webster's tone control to create a family of paragrahphic EQ curves. The control positions include the following:

Fully CCW (Maximum High Frequency Attenuation)
1/4 turn towards CW (from the full CCW postion)
Middle Postion
Fully CW (Minimum High Frequeny Attenuation

Here they are for your use if you should desire to use the flat-transfer technique on old wire recordings. Choose the curve that sounds best on your material.

Craig

[Dan McDonald]

Will try to post some samples for these in a few weeks. Thanks Craig! Dan