They are low tension, 40/60/80/100 gauge, round core, no windings at ball or string end, and brass balls. Very even tone and sound on the bassy/mid range not brights. What else can I look for that might single these out? They came on a used bass from a store so no way to ask the previous owner.

I had some similar strings with no indication of who made them that I bought for $5 a set from an eBay seller years ago. Their sound is like what you described. I wish I knew where to buy more or even something similar.