That's a fun statement. I think we already had vacuum tubes and other foundational components that would in theory have allowed someone to build a CD player a 100 years ago or very close to that. If they would have had the knowledge.

For starters, CDs are not very dense, you can see the data with a microscope: http://www.pmonta.com/compact-disc-microscopy.html

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kibwen 12 hours ago | parent [-]

In addition to the circuitry, I was also assuming that the laser would pose a difficulty.

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Avamander 9 hours ago | parent [-]

It doesn't really require a coherent light source, although that does allow further miniaturization.

	▲	kibwen 4 hours ago \| parent [-]
		I think it would be fair to allow a hypothetical 1920s CD player to occupy most of a room. I'd be interested to see exactly how hard it would be to produce such a thing using the available technology of the era, though I'm still somewhat skeptical regarding the complexity and precision required of the laser motor (which unlike a vinyl needle needs to be controlled manually, rather than just following a groove mechanically) and the spindle motor (which needs to accelerate precisely depending on the laser's distance from the center, unlike a record which revolves at a constant rate).