At W. Cardone Productions our business is to work with legacy audio/visual equipment. By definition, that means equipment that was manufactured for a different age. As a consequence, on rare occasions we run into glitches as in the present case.
We recently acquired a project from a local radio station to duplicate to digital over 30 years of broadcast archives. We wrote up a detailed blog post on this which you can review for how this was accomplished.
The glitch that we ran into was solved by using an APC C2 Power Filter, pictured at the right.
So, enough of the small intro talk. Let’s talk about this absolutely fascinating rare event that we experienced.
As noted earlier, we have been duplicating to digital over 30 years of broadcast archives from a local radio station. Media used over 30 years included primarily the everyday consumer audio cassette. It also included a number of DAT (digital audio tape) cassettes and miniDiscs (optical media). We completed duplicating over one thousand individual media pieces with no glitches, operating with perfection.
On one cold day in December, however, a periodic glitch materialized on four of the nine audio input stereo tracks as pictured on the right. Here it can be seen that every 12 seconds an unknown interference “glitch” materialized. The glitch was of the type that nearby cell phones exhibit though we were not interested in identifying the actual source.
Why is it that we were not interested in identifying this likely cell phone interference? The reason is really quite simple when you apply logic. Suppose that we identified the cell phone causing the glitch. We had been operating in perfection for over two months downloading flawless music audio and then one day with great surprise a glitch that necessitated discarding one entire group of 9 hours of audio. If we identified the likely problematic cell phone and turned it off, why should this not happen again with different circumstances? The obvious solution was to neutralize the incoming effect.
It was not hard to identify the affected audio. We were only seeing this effect in the ADAT audio, just eight audio tracks. Those eight tracks came from one source. We simply used the APC C2 Power Filter to filter its 60Hz AC Mains input. To do that, we unplugged the AC power plug of the ADAT audio interface, plugged it into the APC C2 power filter, and then plugged the power filter’s power input to the AC mains power source. Problem solved as illustrated by the photo below. There are no glitches.
So, why is it that we are seeing this now when in the days of this audio deck equipment (i.e. 1990s) it was unheard of? The first consideration is that cell phones were somewhat rare in 1995. But more importantly, entertainment equipment designed and manufactured in the 1990s did not protect against the electromagnetic interference (EMI) that we are seeing today. EMI is far more prolific in the 21st century than at the close of the 20th century.
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