B and K Refernce 2220 Next Step

I am looking to upgrade this amp, does anyone have an opinion on where I can go from here for about 1k used or should I keep what I have for that price range? I am using the amp to power Sonus Faber Concertos (The bookshelfs) so I dont think I need a lot of power.

My system is a VPI scout with Granite 770FP preamp

Thanks, any input would be appreciated