[X4U] Powered speakers

[eleventhvolume]

I recently inherited a pair of small speakers that I'd like to be able to
use. Unfortunately they have a single lead which combines both audio and
power (there's no other lead or socket on them). The small jack plug doesn't
fit into any of the sockets on my Macs. These speakers are pretty similar to
Apple's golfball-like, transparent perspex ones of yore. There's no
manufacturer's mark on them to identify them though. Does anyone have any
suggestions as to how I could use them for their original purpose or are
they destined to be paperweights from now on?

Thanks in advance for any help you can provide.

All the best, Colin.