How much did the upgrade cost, is you don't mind me asking.
Telling if Bryston pre has upgraded power supply..
Bryston upgraded the power supply on its BP20/BP25 pre-amps a few years back. The following was posted by James Tanner (Bryston VP marketing) on the AudioCircle Bryston owners circle. He is talking about how to recognize by serial number whether a given pre-amp has the upgraded power supply...
"New MPS-1 Power Supply – BP 25 = SN: 251553, BP20 = 221495"
"New MPS-1 Power Supply – BP 25 = SN: 251553, BP20 = 221495"