current use is for watching movies / series on netflix on a nexus 7 tablet , though occasional use with a vintage sony 818 mp3 player.
 
utterly spectacular analog-sounding output  via koss porta-pro´s , which makes a match to rival much more expensive stuff -  at least the porta-pro´s beat my other headphones , namely shure 530 , and sennheiser 280, which despite similar specs sound thin and lifeless , and gary explains why, and i quote him from an email (one of many always courteous, patient, prompt, unfailing) : "The copper wire that is used to wind the coil for the driver, they picked the right type of copper, thickness, and number of windings for the wire. The mylar material they used for the driver, (titanium coated mylar in later versions) much have been light weight enough yet still rigid to reproduce accurate audio. The holes in the back of the driver were enough to let the right amount of air pass through. Everything seems to have worked out pretty good with the Porta Pros, especially for the price. [ditto for the amp ! (my comment)] " .
 
my wish for a bass adjustment is so that finicky headphones like my above-mentioned might be thus ass-kicked to produce decent sound