Um, ... uh, ... huh?!? I'm not sure I understand your question here, Mitty. Is this a hypothetical experiment to see if it's possible to formulate a preference between two combos without knowing their rated power output and speaker(s) configuration/brand/magnet-type? Kinda like a half-blind comparison based on, what, brand/maker, tone stack, control features, total weight, physical dimensions, ..., etc.?
It's an amplifier. Power and speakers are basic essential information. Can you successfully compare cars trucks vehicles without knowing power and seating configuration?
I agree, somewhat. I think different tones due to different speaker sizes was more common in the "good ol' days" before cab design became more advanced. I used to be a 15" driver snob, but the 2x10" Rumble 500 changed my mind, especially when compared to my Bassman 115 Neo cab. I cannot hear any significant difference between them!
Well, correct me if I'm wrong but, I believe the point of amp output ratings is to give a relatively comparative indication of maximum usable volume for using in various venue sizes and situations. Of course, there are apples and oranges in the marketing mix, especially when one brand uses only peak or program ratings to seem more powerful than the RMS or continuous ratings; and differing levels of conservative versus aggressive ratings tendencies/philosophies.
But, the fact that most amps are not always, or even very seldom, if ever, operated at their max usable volume makes it difficult to indicate their comparative tonal "quality" throughout their volume range, without many intricacies like
frequency curves.
Likewise, I believe speaker size(s) can be a useful indicator of comparative sound pressure levels (SPL) available to affect volume and tone. But again, there are no absolutes here, since differing speaker parameters can radically affect SPL.
Thus, I submit that, although power ratings and speaker configuration are not the only information needed to definitively compare combo amps, they are very useful basic information points for initial consideration for certain venue sizes/situations. Then, using more detailed information, ultimately culminating in actual hearing and playing experience, one can more quickly arrive at an individual preference between combos.
Yes, I, too got into a VERY, VERY loud country cover band that had me chaining my Bassman 150 1x12" combo to my Bassman 250 1x15" combo, both continuous ratings, and still feeling underpowered!!! (Although I do admit a reluctance to "dime" my amps.) Yet, somehow, the Rumble 500 2x10" combo at just 350 watts continuous, by itself, finally satisfied all my needs there!!! I did add my BM115 Neo cab, for the full 500 watts, at a few outdoor venues, but ended up turning down so much I gave up using later, even outdoors. (I sometimes took it and stacked it "just in case", but never actually connected it!) Thus, I have ... Rumbled On!