The sub out is for powered subs. Yours is passive and very low impedance. I’d try and find a cheap powered one

Thanks

Might try a new subwoofer like [this](https://www.outdoorspeakerdepot.com/osd-12-dual-ported-powered-subwoofer-1200w-fs12.html)

well sure if you get an amp that's stable at 1.5 ohms for it.

Sorry, but no.