With the low current draw, it should be easy to use for long periods. If someone wants to make it REALLY easy, use Lithium Ion cordless tool batteries, so the charge level is easy to see and they can be swapped between LPs and there's no break-in period.
I look forward to peoples' comments about that.
5-6 Ah batteries are a helluva lot less money than this crap.
If you look at the actual energy used by small electronics like turntables, streaming devices, DACs, etc, I'm surprised the DIY community hasn't jumped all over cordless tool batteries- the Chinese knock-offs are good and cheap. Not sure any are actually made in the US, but if using foreign-made is a problem for someone, they're kinda screwed because the battery cells are made there, too. Closed cell, AGM, Carbon Foam or Lithium Ion batteries for other applications would work, too- many battery companies still make their products in the US.
WRT sag, look into guitar players who search far & wide for 'just the right rectifier' tube- they read about a vintage amp that has 'wonderful sag' and have to have it, even though it would never be the same with their modern design. They'll pay over $100 for one tube from the '50s, to put it in a $300 POS amp because they think they'll sound like angels when they play.
I'm sorry, I was wrong- apparently, a NOS GZ34/5AR4 can be close to $300.
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