Originally Posted By Andrew
Originally Posted By Mojo
What's that gold plate in the middle?


That gold plate is likely a piece of plated copper. It is the central "star" ground point for the amplifier, and all ground returns (transformer centre-tap, safety earth, main power supply capacitors, amplifier PCB, input stage PCB, speaker negatives) will all connect to this bus plate.


Indeed. It must be nice not to have to worry about fast transients, surges and ring waves on I/O in audio. Then you can get away with a pseudo star ground.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated