Different power supply units leading to visible S/N ratio differences

Different power supply units leading to visible S/N ratio differences: Using the "Gain" optimization function in AnalogMagik, I measured the S/N numbers on iPhono 2 with its own switching-type PSU (Figure 1) and a large linear PSU by Acopian (Figure 2). The difference is about 1dB and quite consistent in various measurements.

AnalogMagik 有個原本用來找最佳放大倍率的功能，我以它測了不同電源供應給 iPhono 2 的 S/N （訊噪）比。圖一是原廠的切換式電源，圖二是 Acopian 的線性電源。測出的差別不大，約1 dB左右，但數據相當的 consistent。