There is a lot of discussion on ASR about damping factor (DF), that is worth a search, so recommended.
Your observations aside, for the moment, align with a DF, confirmed by Stereo.de.
Stereo.de AHB2 damping factor measurements is an outlier.
Here are the Benchmark AHB2 for damping factor:
Here are the DF measurements from SoundStage:
View attachment 231747
Damping factor is most important in bass frequencies but with these we can compare 1 kHz.
Stereo.de 48, Benchmark 254, and SoundStage 225.
I have no idea what Stereo.de is doing, and perhaps they don't either.
Concerning your observations, the perhaps 48 seems low but is still higher than necessary.
I observe no issues with the AHB2 and tight bass driving the Salon2s full range.
I have disconnected the upper section and listened to the bass 150 Hz and below on the Salon2s which that are -3 dB 23 Hz and this cannot be described as tight with any amplifier. I have driven there with Parasound amps with DF spec'ed at > 1100 and I find no audible difference in bass. If anything, the AHB2 is better, perhaps due to its tightly regulated power supply and minimal phase shift.
- Rich