I know it's been a while but I had to create an account to reply.
From '76 through '78 I owned a pair of L520s. Walnut wood veneer and cloth covers. The woofers used rubber surrounds, the tweeter the soft cloth type. Black matte in front, flat back in back, with two screw in posts for connections. They sounded almost like a prototypical "monitor" speaker. Not very deep bass extension but very FAST and accurate bass and a very clean midrange with good -and sweet- treble extension. We used to call that the "East Coast" sound vs. the "West Coast" sound of the JBL L100 Century (with a boomy deep end).
I sold the pair to my friend when I upgraded to the L810s ( which I still own but seldom play ). Those added the midrange dome for more accuracy in the midrange, dual 8 inch woofers for much deeper bass, pretty much the same treble and overall much more power capacity. If the L520s went to 9.5, the L810 go to 11. Heck, I blew a midrange playing Eric Clapton with a 150 watt amp.... Figure how loud that must have been... But CLEAN... as all ADS speakers were.
Quite a few of my friends heard my L520s and bought them. Some of my college friends lived in an old house with two pairs of L520s in the living room, one speaker per corner. It sounded awesome in a 14'x24' room.
So, did you get your speakers fixed and setup?
Make sure to drive them with an amp with good current drive (I recall they are 4 ohms... huh?) of sufficient quality. The old Harman Kardons and Kenwoods of the day drove them beautifully.
As a vintage speaker, they lack the imaging of newer speakers and the treble is a bit rolled off due to the soft dome tweeter, but their deficiencies are of omission.
Oh, btw, you wrote your wife was not happy with your LP purchase. I realize a year has past, but I would be more than willing to help you out with that problem. ?
Oh, btwII, the rubber surrounds of the woofers in my L810s are still working fine. It's been.. hmmm.. 41 years now? I have no reason to believe the L520s would not last any less.
