For what it's worth, in the early 1950's, from 1951 until 1954, there were times in Minneapolis and
Chicago when my father would have to use Fairchild's Pic-Sync system to assure correct pitch/speed
in his recording truck. The truck's power panel had a frequency meter that monitored the power line.
He said Minneapolis in particular had unreliable power frequency in those days. The tradeoff with
the Pic-Sync system as originally designed is that there's a sharp rolloff above 10kHz, because the
Pic-Sync signal is at 14kHz. However, using modern methods to lock to and then remove the Pic-Sync
signal, in tests done by Jamie Howarth and myself, we recovered usable audio above 10kHz. There
seems to be recorded information up to, at and above the 14K frequency, the rolloff occurs only in
the playback. When the Plangent Process is used to lock to either bias or the Pic-Sync signal, the
band of the tone is very narrow and can be notched out, leaving a lot of audio information that
would have been sharply rolled off by Fairchild's Pic-Sync playback system (resolver) or similar
devices. We found surprisingly little beating and other interaction with music audio. I have to say,
the whole thing surprised and impressed me, the quality and the frequency range of the audio
recovered. I would certainly never use an analog Pic-Sync resolver again, for any Pic-Sync tape.
In contrast to the variable Midwest power frequencies in the early 50's, another power system story
oft-told by my late friend and mentor Bob Eberenz concerned Manhattan during hot summers in the
60's. While the frequency would be rock-solid 60Hz, the voltage could drop as low as 95V in Midtown,
overheating the wiring and various pieces of equipment. Bob obtained some massive step-up
transformers, and could thus keep the control rooms running on 110-120V under most circumstances. He
said the big lines coming into the building in the sub-basement would be so hot you could pour water
on them and it would boil right off.
-- Tom Fine