Why don't you keep the MF kw500s and replace your receiver with a good integrated or preamp? My son has the HK 3380 (identical to the HK 3480 minus a few watts), and although it's pretty fast and transparent in the mid-band (at the expense of everything else), I can tell it would be a poor match for the SF Concerto Grand Pianos. Nor would it make a good front end for the MF kw500s. Get a nice little integrated or line stage for your KWs.
May I suggest the Parasound Classic 2100? Although I haven't heard it, I've gotten a high recommendation on it from an experienced enthusiast with similar tastes to mine. It also has built-in phono preamp. Another possibility might be this Antique Sound line stage.
If you're dumping the KW500s because they didn't sound good downstream of the HK 3480, you're barking up the wrong tree. The HK isn't a good enough front end for the MFs.
May I suggest the Parasound Classic 2100? Although I haven't heard it, I've gotten a high recommendation on it from an experienced enthusiast with similar tastes to mine. It also has built-in phono preamp. Another possibility might be this Antique Sound line stage.
If you're dumping the KW500s because they didn't sound good downstream of the HK 3480, you're barking up the wrong tree. The HK isn't a good enough front end for the MFs.