I don’t know your sub so I might be off "bass" here (sorry), but when I can get a powered sub like this that goes down to an honest 20Hz for 300 bucks I’m not sure I’d mess with buying an amp for an old sub...
https://www.ebay.com/itm/302887582892?ul_ref=http%253A%252F%252Frover.ebay.com%252Frover%252F1%252F7...
Best of luck.
https://www.ebay.com/itm/302887582892?ul_ref=http%253A%252F%252Frover.ebay.com%252Frover%252F1%252F7...
Best of luck.