Hi,
Since you have $3500 to spare for a power amp upgrade, I suggest you consider other brands. Try to audition Rogue, Adcom, Rotel and other mid end power amps. I've tested ADCOM GFA-5500 vs MODWRIGHT KWA-100 paired with an Audio Research LS-7 tube preamp and IMO the ADCOM sounded more musical. On the contrary when I tested both power amps on a MODWright hybrid preamp, the KWA-100 sounded better with clearer highs, smoother mids, more detail and deeper soundstage. Again, it's all about component matching. Don't be fooled on cosmetics. You gotta listen with your ears and not your eyes.
Since you have $3500 to spare for a power amp upgrade, I suggest you consider other brands. Try to audition Rogue, Adcom, Rotel and other mid end power amps. I've tested ADCOM GFA-5500 vs MODWRIGHT KWA-100 paired with an Audio Research LS-7 tube preamp and IMO the ADCOM sounded more musical. On the contrary when I tested both power amps on a MODWright hybrid preamp, the KWA-100 sounded better with clearer highs, smoother mids, more detail and deeper soundstage. Again, it's all about component matching. Don't be fooled on cosmetics. You gotta listen with your ears and not your eyes.