ADS L 520

I have a chance to purchase a beautiful pair of ADS SL-520s for $50 for the pair. I am currently running a pair of mid 1980’s Klipsch Heresys with a low 2a3 powered tube amp. Any opinions if this would  be a improvement or a downgrade from the current heresys that I am running now. Thanks. 
Give them a try. 50 bucks sure ain’t goin’ to break the bank!
keep them both and educate your ear !!! they are cats and salmon different and both have manifest strengths..

but Lord, please dont stack them on top of each other...

i still run a pair of l520s in my basement and love 'em--very resolving tweeter and great bass for such a small speaker. also very efficient and easy to drive--as stated above they're a different animal than the heresy, but i'd grab 'em for $50
I still run 520's in my upstairs AV system. Great for movies, etc. $50! Go for it.