Both Mechmini2’s built with lubed vintage blacks (104) and sprit 63.5g springs (106) as per usual.
The Purple has a 1.5mm brass fixed layout plate, the Black a 2mm copper fixed layout plate (although by my callipers it’s actually 1.81mm consistently).
I would have preferred to do this with 2mm on each side but at the time of purchase I was unable to find a 1.5mm copper supplier. I think the sound profile of the two comparatively is interesting enough to warrant the test with the proviso that it’s remembered that the difference in thickness will have an effect.
On the feel the copper is slightly more rigid, very very close though, I suspect at 1.5mm that would be reversed and the brass would be marginally more rigid conversely. On the sound, in this case, I’m all for the copper which has surprised me, it has a softer more thud like bottom out in my opinion.
Plates are from laser boost (they’ve done a few for me at this point for these tests).