Morgan already owns a colour, a mark and a point of view. What is missing is a system that applies them the same way twice. This is that system, built entirely from what is already on morganamps.com.
Morgan gold appears 19 times on the current homepage and it is the only non neutral in the whole identity. It is also literal: three products are named Gold, and gold grille cloth is what you see across the front of a Morgan cab. So the accent has a referent in the physical product, which is why it can carry the entire system alone.
Ratios computed by the WCAG 2.1 relative luminance formula against the #0B0A08 ground, not estimated. Every pair clears AA for body text, including gold, which is what lets the accent carry links rather than decoration only.
morgan-amps-logo-dark.svg.Open Sans stays. It is Morgan's current face and it is not the problem: a $89 page builder's layout is the problem. Keeping their body face and fixing everything around it is a stronger argument than replacing the lot. Archivo carries display, IBM Plex Mono carries every figure.
Morgan's own product photography is already right: square, evenly lit, shot straight on against black. The system just has to stop fighting it. Every plate crops 1:1 so a grid of amps lines up on the faceplate rather than on the cabinet corners.
Morgan's own copy is already the right voice, and it is unusual: plain, specific, faintly impatient with marketing. "Joe will be the first to tell you that tube amps are not rocket science." That sentence does more work than any tagline.
Keep: concrete nouns, real numbers, the builder's own asides. Name the transformer. Give the dimensions. Say who it is for.
Drop: superlatives without a referent, "premium", "curated", exclamation marks in product copy, and any claim the site cannot support.
That is already the line. It does not need improving, it needs a page that earns it.