Mixing amps like what you're talking about almost never sounds right. If you're able to try a tube amp without committing to a purchase, then do it. You'll probably need a crossover to get the levels right. I say fix the problem directly. If you really love the speakers and know you want to keep them for a long time, it would make more sense to get a more forgiving power amp and speaker cables. That said, more audiophiles have gone broke trying to get B&W's sounding right more than any other speaker. That's why most of us had B&W's and not have them. The midrange on your speakers is great. Fast, clean, articulate, etc.. It just draws you into the music. The highs are always a problem. Also, I wouldn't go by your memory of how they sounded when you first heard them at a dealer. Now that you've had the speakers for a while and know how they sound, hearing the original setup again may sound completely different.
Tube + SS bi-amping B&W 803 D3s?
In the constant quest for incremental gains and chasing the high from first hearing these speakers at the dealer, I have been considering bi-amping my B&W 803 D3s with a tube amp for HF and using my current Parasound A21+ for LF. Anyone have experience with this type of setup or recommendations for tube amps that may be particularly worth looking at?
FWIW, I tend towards warmer sound. The speakers are crystal clear but the Parasound tends towards brighter sound with them. The addition of the C2500 and the SVS subs has definitely helped, but I get the sense there is still some performance left to find.
Current setup:
NAD C658 Streaming DAC
Pro-Ject Carbon Debut TT with Sumiko Wellfleet cartridge
McIntosh C2500 Pre-amp
B&W 803 D3 Floorstanding Speakers
SVS SB-3000 subs x2