Maybe a Nord PRE-A preamp to complement the Nord poweramp?
Beauty is only skin deep. In 1980, I brought home a NAD integrated amplifier to try with my Advent speakers despite my opinion that the NAD was ugly. It blew away my Marantz receiver and I bought the NAD. What a great sounding integrated amp that was. If you can, try as many preamps as possible making sure the output impedance is compatible with your amp. Good luck!
Check out the Emotiva XSP-1 It is a two channel pre . It seems ruler flat to me . Any recording I play through it can be played at any volume without fatigue . dead quiet and just gets out of the way . I picked mine up in a group package I picked up to flip . This Emotiva is a keeper . I don't know what I would have to spend to get better results , and I cannot imagine what aspect could even sound better .
It has tone controls if desired or defeatable by going "direct" mode . Has xlr and rca inputrs and outputs , Phono too .
I am currently running a Nad silverline s200 amp with it into King Sound speakers and Adam audio Tensor Gammas . Makes both speakers shine
+1, @stringreen, I also recommend the OP consider one of the Ayre Acoustics pre-amps. Please see:
There are six Ayre pre-amps for sale on Audiogon at several different price points.