yay: My USB speakers arrived
boo: They're usb-POWERED, not usb speakers. Still got to plug them en
yay: Of course my old X200 has a line out/headphone jack
boo: Jack is busted, makes no electrical connection.
Bleh. 
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@RL_Dane there's a utility I used at one point that can remap the sound jacks, so you can use the mic as line out. I think it was this, but I'm afraid I don't remember for certain and the machine in question is long gone, so I can't check.
https://www.alsa-project.org/main/index.php/HDA_Analyzer
If your mic jack is TS, it'll be mono output. If it's TRS, you may be able to get stereo.
Thanks! I'll look into it
@RL_Dane Looking further, I think it was actually hdajackretask, not hda-analyzer