Good quality amplification (not necessarily big power output) will make your LS50 perform optimally. The LS50 need good quality amplification and upstream electronics, as somebody has already suggested here, in order to hear what these speakers are capable of.
I heard these KEF LS50 paired with the Naim Uniti Nova (streamer/DAC/integrated amp), which is an all-in-one box solution, and they sounded fabulous together very musical very fluid solid punchy and had excellent musical drive or rhtymic drive. The Naim Uniti Nova is rated at only 80 wpc @ 8 ohms and its power amplifier section uses class AB design.
The Naim Uniti Nova has a very good digital streamer/DAC as well as integrated amp sections.
However, the Rotel RA-1592 integrated amp and the Musical Fidelity M6Si integrated will also make your LS50 to sing. But as you upgrade your amp and upstream electronics the better they will sound or perform. Unlike other speakers within their price range (sub $2k/pair bookshelf speakers) these KEF LS50 would have to be fed by quality electronics in order to perform and sound good.
