Yes, there is a(n audible) difference (IMO!) though they are fairly similar.
Both of these models go back to the "AmpliTube 2" era. The
S100 was part of the original Hendrix collection and was based on a Marshall JTM100. It was in some senses replaced in the updated Hendrix collection by the
JH Gold, which (I kind of get the sense) models an actual Hendrix JTM45/100 very closely. The
JH Gold has controls that are virtually identical to those of actual JTM45/100s and/or Superleads (and Super Basses), including the ability to bridge/jump the inputs, and there is no master volume. The
S100, in contrast, has slightly less authentic controls; e.g., e.g., there are separate master volume and preamp gain controls.
Marshall did not introduce master volume controls on actual amps until about 1976/1977, with the "Marshall Master Model 100w Lead #2203" -- which is what I believe that the
Vintage Metal Lead (originally part of the "AmpliTube Metal" collection) is actually based on. (The official designation as "Marshall JMP100 head" is not very specific). The historical physical amps went through a few circuit revisions and eventually, by around 1981, evolved into early JCM800s.
If you dial in the
S100 with fairly vanilla EQ settings (Reverb off) and the master Volume and pre-amp Gain both all the way up, it sounds very similar to the
JH Gold with the same EQ settings and the Normal channel dimed. Then, both of these sound
fairly similar to the
Vintage Metal Lead set the same way as the
S100. They are all, after all, intended to represent various Marshall amps from the period (roughly, I would guess) 1966-1978ish -- so they can be expected to sound at least
similar.
Still, I think the
S100 and
JH Gold are the most similar (naturally enough, as both are intended to catch a Hendrix vibe), though I prefer using the
JH Gold because I think it is a slightly more authentic model -- and it's a more recent model, of course! I think you can more readily hear the difference between either of these and the
Vintage Metal Lead. Nevertheless, if you want to get the effect of slightly different 100w Marshall vibes on different tracks (as if one were recording guitars tracked through several different amps of the same basic model), you can use them all in parallel in your DAW. Or, I suppose, you can blend them within AmpliTube, too, in multi-amp chain configurations.
The
JH Gold is one of my "go-to" AmpliTube models, though if new models based more authentically on, say, an early '70s non-master-volume Superlead and a late '70s master-volume 2203 (not to say an early/mid-70s Superbass) were added to AmpliTube 5, I would certainly buy any and all of these instantly.
IMO, you can never have too many vintage Marshall amp models.
If I were going to pick just one of the existing models, though, it would be the
JH Gold, largely because it is more recent and "more authentic". For a second, it might be the
Vintage Metal Lead, mostly because I think it's that little bit more different than either the S100 or the JH Gold. But, of course, I actually have all three models.
by NewEnglandSynthOrchestra » Sun Apr 18, 2021 11:30 pm 
But the AFD100 in the Slash package was an attempt to reverse engineer the sound of the modded-Superlead (technically, apparently a modded Super Tremolo 1959T 
