From speakers mentioned above, Q2050 is easiest, lightest load for amplifier. So 3116/18 performs good with heavier load, 3250/51 need lighter load ? Do the 3250/51 sound weak to you? Funny.
Purely technical and just looking at the tpachip, forgetting the outputfilter, the BD amplifier 3116/18 performs better, distorts less, when inputsignal goes up, so when more output is needed the BD amps distort less.
The AD amplifiers tpa32xx distort less with lowest input, when less output is required, increasing the inputsignal, raising volume, and distortion goes up.
With good nearby powersupply the BD amplifier has dominant 3rd harmonic distortion, create distance between powersupply and chip and 2nd harmonic distortion increases. Increasing output for the ampboard(including outputfilter) gives dominant 3rd harmonic.
With good nearby powersupply the AD amplifier has around equal 2nd and 3rd harmonic distortion, create distance between powersupply and chip and 2nd harmonic becomes dominant. Increase output and 2nd harmonic grows more than 3rd harmonic, but 5th harmonic becomes dominant.
Different amplifiers chips, should sound different unless other parts dominate sound.
