Older speakers like that use always on transformers, constantly wasting energy to keep the core energized. You’re correct those cannot be made any more, they must use efficient switch mode supplies.

Not directly answering your question, but I’m an avid Gardner with 15 years of hobby experience and I stopped growing spinach because it attracted so many pests and I don’t spray. I found varieties of kale with delicate leaves better because they grow faster, were much more bug tolerant and tasted as good or better.

If you have some outdoor space and interest, growing some greens for yourself is very easy if you get the right varsities.

I know way too much about the propagation of plasma in fluorescent lighting. When you first hit a fluorescent tube with high voltage you need some cosmic radiation to rip off the first barium ion off the cathode which causes a tiny little lightning strike of plasma that skitters across the inner surface of the tube. Once it makes its way across the length of the tube to the anode you now have a conductive path. This path then grows tremendously until it envelopes the whole cross section starting from the anode and works it’s way back to the cathode until the whole tube is filled with wonderful plasma that makes light when it excites the phosphor coating.

+1 on this idea, going to toss in my recommendation for an AMD 5600g second hand. Its basically a laptop CPU with built in GPU that handles my jellyfin transcoding without issue and has a super low idle power rating if you pair it with a quality, small PSU.