A very nice Sansui AU-555A was on the workbench for a complete restoration and upgrade. Part 1: Power Supply The stock C001 capacitor (2200µF/63V) was replaced with a 6800µF/80V low ESR type; note that the voltage rating of the replacement was increased to 80V since this capacitor is subject to ~60V. Similarly, the capacitors at C002 (470µF/50V), C003 (1000µF/50V) and C004 (470µF/50V) were replaced with low ESR types rated at 1200µF/50V, 2200µF/50V and 1200µF/50, respectively. The stock diodes, D001 and D002, were replaced with 2A(200PIV) soft recovery types. The voltage dropping resistors, R001-R003 were replaced with 1% metal film types rated at 2W.