On Sat, 2026-05-02 at 11:03 -0400, Frank Bures wrote:
> I've had an original Cream LP in the early 70's that had 50Hz hum recorded 
> in it.  The song would end and the hum would become obvious. Then the hum 
> would end in the between-the-songs gap, it would start again and a second 
> or two later the song would start, masking the hum. And as I say, it was 
> not some pirate copy, it was the official release.  Studio recording, not 
> live.

Very odd.  Usually mastering is a very precision business, with a lot
of attention paid to how you'll cram more audio into a record than it
can manage.  I can only imagine that /that/ day someone was just
watching metering and not listening, a cardinal sin in audio
production.

It's probably worth more, now, to a collector because it's wrong.  :-\

We had an unknown hum loop problem one day while doing a week of sports
filming.  We were using SDI (serial digital interface) equipment, and
the signal was going haywire.  With analogue gear, you'd see immediate
tell-tale signs of what the problem was, but not with digital.  It just
stops working properly, and you have to try to figure out why.

I brought an analogue scope in.  You can't decode the signal with it,
but you can look at the integrity of its shape, and immediately saw a
small mains hum on the signal.  A camera was mounted on a lighting pole
at the edge of an arena, and it'd bitten through the insulating pad on
the mount, there was a small voltage difference between the grounded
pole and the building it was cabled to.  Nothing dangerous, nothing you
could even feel, but it completely disrupted the digital signal.

And that's the kind of thing you could be faced with ethernet cabling
around a house or building.  Small amounts of unwanted hum or noise
that is enough to mess up the small amounts of signalling that ethernet
uses, and no real clues as to what the problem is caused by.  All your
computer tells you about is things like packet loss (the effect, not
the cause).  You need *proper* ethernet test tools to diagnose cabling
problems.

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