ΔE 7.6, close: similar, with a visible difference side by side. Balthasar Gold is a little darker, more muted than Brass.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Balthasar Gold is a little darker, more muted than Brass.
The same difference applies the other way round: Brass is a little lighter, more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Brass on the colour wheel See Balthasar Gold on the colour wheel
All matches: Brass equivalents · Balthasar Gold equivalents