I have a first version Cambridge Audio 540C CD player. A good sounding player, nothing high-end though. Today I popped the hood and took out the bog standard NE5532P opamp. I know, a NE5532 ain't bad but more exciting opamps exist. After removing the NE5532 I soldered in a decent DIP socket (to...

A question about R5 in the Mini3. What purpose does it serve? I can get 5.6R or 6.8R, not 6.2R, can I substitute it with one of these values? If yes, which one? Why carbon instead of metal film? Thanks!