The Trinity 18-watt sIII is modeled after classic Marshall designs, and Stephen's reference to the "original Marshall 18 Watt Tremolo channel" means channel one retains the vintage 1974x-style tone. This channel has a smooth, gainy character with a classic Marshall overdrive, great for vintage rock tones.
Channel two, the TMB (Treble, Middle, Bass) channel, offers more versatility and a cleaner, more articulate sound compared to channel one. It's often compared to a JTM45 but with a tighter low end and a slightly brighter character.
In short, channel one delivers a more gainy, vintage-inspired sound akin to a Plexi or 1974x, while channel two is cleaner and more dynamic, similar to early JTM amps. You might explore sound clips of the Marshall 1974x and JTM45 for a closer comparison.
polytrack