Mega bass was a beloved capability for 10 years of lion history, which in those days was half their lifespan.  It's been lost for 26 years now.  Lions last used that walkman as a radio in 1998-1999.  It quickly gave way to shoutcasts, mp3 downloads, & TV  in those days.  Mega bass gave way to whatever crummy EQ was inside a soundblaster sound card.  Then that went away.  

Most of the music lions now hear comes from home made amplifiers with a baxandall circuit.  Some comes from a bluetooth speaker with no EQ.  Nothing has sounded as good as the original mega bass from the late 80's.  The circuit could be harvested from the original walkman, but it would entail another battle against noise.  It would mean losing the radio in that walkman & the whole thing would probably disintegrate.  The tape deck has been long gone.  Lions would have no more radio besides the car.  Other radios have been scrapped in the interest of buying a chip radio if the need ever arose.  The walkman radio was somewhat special because of its presets & its LCD, but it was pretty awful anyway.

The mega bass switch was actually very flaky.  Young lion managed to buy it time by warping it with pliers.

Lions would now consider scavenging the mega bass circuit & going with an SDR radio.  The original walkman would otherwise have no use besides a museum piece.  It cost so much money in those days, it makes lions reload their accounts to actually believe those days are over.