I agree with all of this, although I don’t think less gain or complex chord voicings would reveal things in a way that would make it clearly obvious which is real.
What I was talking about wasn't less gain. It's the way nonlinearities in the amp or sim change with
differences in the level of the signal from the guitar at a constant gain setting (could be any amount of gain). It's not so much "edge of breakup" behavior - although that's important - as it is
the way the device makes the transition from clean to hairy to fully saturated and back again
. Some devices - including
both tube amps and modelers - do this more smoothly than others, and some devices have "gain hysteresis:" they behave differently in
decay than in
attack. Finally, simple triads aren't what I'd call "complex chord voicings," but they do contain more harmonics than power chords and therefore tend to highlight differences among amps and modelers.
It might make them sound a bit more different,
Agreed, which is why I referenced "differences among rigs." When I'm listening to a recorded clip, I have no interest in which one is "real." They have all been recorded - usually with mics that add their own colorations - and are being played back over my speakers in my listening environment. Strictly speaking,
none of them are "real."
Real amps vary so much in these regards too.
That is a point I've made repeatedly for years. Again, this is not really a controversial topic. There are tubes-only types, but those folks aren't likely to ever change their minds.
With digital, sometimes aliasing or other artefacts can be something to consider
I encountered audible aliasing in the first two modelers I (briefly) owned, but it ceased to be an issue when I got an Axe-Fx. It is also not a problem in Atomic modelers, and I suspect - but have not confirmed - that it doesn't affect other current designs.
I used AC/DC here because a lot of guitarists mention it as a tone that digital struggles with.
I understand. Contemporary guitar mythology holds, among other things, that "digital" can't do the Angus Young "kerrang." Interestingly enough, most of the folks who say that have only ever heard "digital" reproductions of that sound.