Under both Power Amps:
  Solen 'Fast Capacitors' are used for final stages of power supply filters (CLCRC filter for 2A3 plate supply, CRCRC filter for 6SN7 plate supply), and cathode bypassing of driver and output tubes. Interstage coupling caps are Hovland Musicaps. The transformers are for filaments of the 2A3's, and the potentiometers are for 'hum balance'.  The dark brown strips on the chassis are 3M brand 'Silencer Strips' vibration-dampening tape.