The MASS line uses an actual speaker motor inside the box without the cone, so the impedance curve is closer to using a full-on speaker than using a big resistor or a different inductive load.Cool, what is that? Attenuator? Does it have a reactive load?
Yeah give it some more time, and remember, ANYTHING is going to change the feel of the amp.
I agree with you that the low range is pretty much useless. I use mine mainly for recording at home, and have learned to dial it in accordingly, it definitely took some time.
Overall I agree with you though, best for taking the edge off. I personally think that for 'bedroom levels' a tube amp is just never gunna cut it as there is too much of a volume/ tone trade off.