I built and installed the C4S upgrades for my Paramours in May. This reduced the hum considerably, but it is still audible and the Decware Zen produces much less hum. Still, I like the Paramour amplifier very much and am impressed with its performance in the bass, particularly with speakers that other SET amps can't drive well.It's not like Paramour hum is annoying, but you can hear it just a little bit.