October 25, 2010

The last picture tube show

I visit Walmart about once a month. It's off my beaten path, but carries a few items that are so inexpensive it's worth stopping by to stock up. The "site-to-store" free-shipping is hard to resist too. The SKUs and the shelf layout hardly change, which makes the shopping quick and easy. That also makes the changes stand out.

The last time I went a few days ago, one thing stood out: no tube televisions.

Over the past several years, the shelf-space for tube televisions had shrunk to a single side wall. Then half of that. Prices plummeted. At the end, Walmart was obviously shedding inventory. And where Walmart plants its giant retail feet, there for good or ill can be found the smack dab median of American consumer supply and demand.

The television tube is dead. Long live the television set!

Fanatics still buy turntables and tube amplifiers. But the television cathode ray tube is a bulky kludge that has little to recommend over its technological replacements. Like the internal combustion engine, the real miracle of this Rube Goldberg contraption is not that it can be made so inexpensively, but that it works at all.

The CRT is the last true vacuum tube—a filament, cathode, grid and anode sealed inside of glass and depleted of air—found in consumer electronics. For decades after the introduction of the transistor, a television set had two vacuum tubes: the CRT and the high-voltage rectifier that charges the anode. The latter was long ago replaced by silicon devices.

While the typical "radio tube" has a few hundred volts at the anode, the CRT requires tens of thousands. It's a cliche that the computing power of a Cray supercomputer can be packed into a cell phone. Less appreciated is that for half a century, a large proportion of the world's population had a small linear accelerator sitting in a corner of their living rooms.

It's also become a cliche to remark about how complex the technological world is becoming. But as materials science and manufacturing improves, and Moore's and Shannon's laws reach their limits (plus the very non-theoretical problem of heat dissipation), the macro can only grow to the extent that the micro gets simpler.

The junction transistor (1947) is a simpler device than a vacuum tube (though the underlying physics is a bear). The field-effect transistor—most common today—is simpler than the junction transistor (and more analogous to a vacuum tube). It was theoretically described in 1925, but the necessary silicon purities weren't possible until 1952.

Philo Farnsworth's scanning electron beam television was the best version possible with 1920's technology. The plasma television is a lot simpler. It was conceptualized in 1936, but the electronics and manufacturing techniques would take 30 years to catch up. And another 30 years to make economical as a CRT replacement.

An all-electric car is mechanically much more simple than the internal combustion engine. But as is often the case, we're better at improving old technology than making new technology affordable. The laws of thermodynamics—the enormous amount of energy stored in a gallon of gasoline—is the higher hurdle here.

With consumer electronics, when all that has to be moved are electrons and photons (and a finger to operate the remote), Moore's law rules the roost. Smaller, cheaper, faster keeps getting smaller, cheaper and faster. The CD wiped out a century of technology in a decade. The DVD took out VHS even faster. I now have a tiny Nokia and no landline.

And yet we still dial phone numbers. Will we still watch the tube after the tube is gone? I will for the time being. My boxy old JVC is good enough. Though if I ever move, it won't come with. When I was at Walmart, I easily lifted a flat screen the same size. The last time I moved that JVC around, I nearly put my middle-aged back out.

Besides, winter's coming. It's the closest thing I've got to a fireplace: big, warm, and impersonally friendly.

Related posts

Complex simplicity
The old brand new
HDTV on the cheap
The drama of the PCB

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# posted by Blogger Joe
10/26/2010 9:24 AM   
In a few respects the tube is still superior to its various replacements. Only the high end LCDs have the same color reproduction and getting high resolution was relatively easy. Plus the "refresh" rates have still not really been equaled by any replacement. Then there's the resolution scaling issue--easy with a CRT, doesn't really work with anything else.
# posted by Blogger Eugene
10/26/2010 2:07 PM   
The question is ultimately about where the fidelity, price, and "good enough" curves intersect. Just as the ideal light source will always come from heating something (like tungsten) white hot, digital forever approaches analog, never equaling it, but eventually falling within an acceptable margin of error.

Or is given a boost by another compelling variable, such as noise or ergonomics.

My first reactions to getting satellite and DTV were the same: "Wow, no noise!" But because of signal compression (as a general rule of thumb, the fewer the number of subscribers, the narrower the bandwidth allocated to a satellite channel), my TV Japan signal has less fidelity than local over-the-air DTV.
# posted by Anonymous Dan
10/27/2010 6:03 AM   
Great writeup.

I have had a 42" 720p Panasonic Plasma for a year and the price / performance ratio puts CRTs to shame.

As one who does not care for LCD TVs I find the dominance of LCD over Plasma very interesting to observe. It appears the mass market prefers brightness and color intensity over total picture integrity. Then again do not the critics offer a similar complaint about the American preference for sports cars, entertainment and food?
# posted by Blogger Joe
10/27/2010 9:34 PM   
price / performance ratio

Seriously, Dan?

No question that Plasmas are nice, but with prices $950 and up for just a 42 inch, you've got to be kidding me.
# posted by Anonymous Dan
10/28/2010 2:50 AM   
$479 at Costco [Model TC-42PX24]

# posted by Blogger Joe
10/28/2010 6:47 PM   
How does the 720p handle your Blu-Ray player (which I presume upsamples to 1080p)? And what does it do with 1080p or 1080i content? Does the player down convert it or the TV?
# posted by Anonymous Dan
10/29/2010 4:30 AM   
Blu Ray plays fine. I use HDMI which I believe allows the devices to negotiate the supported resolution. The only real downside to this particular Panasonic is the screen is glossy so you have to be mindful of light sources that might cause annoying reflections.