I picked up a pair of vintage (circa 1979) JBL K140's in old Sonic 1X15 stackable cabs today. The speakers are both original never re-coned and with sequential serial #'s. The cabs are very clean and solid too. The only thing I immediately noticed after a few thumps on the old bass was was that the speaker inputs were polarity reversed. JBL uses the Black positive convention but the person who put these together didn't seem to know that. After a quick switching of the input wires I hooked them up. Whoah! The first head was, umm, my first head ever, a crusty old Kasino (Kustom) 200. Terrifying lows and smooth overdrive. I'll find uses for this new tone in my studio. Second head was my trusty Hartke HA3500. Tube pre at 3 o'clock, SS pre off, EQ out and countour controls flat. Holy yikes, I couldn't it past 3 without my heart skipping beats. Price paid was $300 for the pair, the guy even delivered them from 2 hours away. Thoughts and opinions are well appreciated, these are my first JBL's and so far, I'm smiling like a fool!