Allan said:
The only substantive reply to my question was based on the assumption
that I was looking for valuable or rare tubes. I just want to get a few
tubes to experiment with. I still don't know where I can find them by
scavenging contemporary discarded electronic devices. Are they really
no longer scavengeable? If so, I'm aware that one can still purchase
tubes from contemporary suppliers and that they aren't expensive. I'd
just rather get them by scavenging them.
At this point, you will come across very few discards lying on the sidewalk
that have tubes in them. It's well past the time, decades ago, when
people were still routinely using them, so they've long been tossed out.
People would toss them because the equipment had broken down and it was
no longer worth repairing, or toss them because they'd rather switch
to solid state equipment.
What remains is not likely to be tossed, because enough time has passed
that people would now see them as collectables. The owners will mostly
know that it is valuable in some way, be it money or just rarity at
this point.
That's not to say you won't see the occasional tv or radio that uses
tubes, but it will be quite rare. I think it's been about a decade
since I came across a tv or radio that had tubes in it. I did see
a couple of oscilliscopes a few years back that had to date from
the tube era, but you aren't likely to see those in the garbage very
often, whether they have tubes or don't.
Keep in mind that in the tube era, the average household have very
little electronic equipment. A tv set or two, a radio or two, and
maybe some sort of stereo system (or just a portable record player).
There just wasn't the level of electronic gadgetry back then. It
was the coming of solid state, and especially of ICs, that made
it feasible to get a lot into a small space, which meant a lot
of new consumer items. The IC and microprocessor became so
cheap that not only were there a lot more gadgets around the
house, but even pretty dumb things had clocks and such built in.
35 years ago, when I got interested in electronics, I never
saw much more than tv sets and radios waiting for the garbage trucks.
Even if you do come across such things, many of them were "AC/DC",
ie they ran right off the AC supply with no transformer, and in
order to do that they ran the tube filaments in series, and in order
to do that the tubes would have different filament voltages that
when added up would require little or no dropping resistor from
the AC line. So even for experimenting, the tubes from such
consumer equipment weren't so useful, because you'd not be
duplicating the tube lineup, and then would have to fuss with
a 50 volt filament for that tube, and a 35 volt filament for
that other tube, and so on.
Michael