Diodes and RF Chokes

[shovelhead138]

I had an old friend who is our head Electrical Engineer at my work tell me that I should use a Diode on the back side of my DC adapter to prevent voltage backing into the battery lead. He also said I should put in RF Choke downstream from where the battery lead / dc adapter enters the circuit to eliminate buzzing.
Do y'all agree? If so, would y'all have links of what diode i could use. The RF Choke he had was this bulky radio shack component. If these are necessary, is there more compact choke used for the fuzz pedals. He is out of country now, so i couldn't finish bugging him.
Thanks so much 

[Skruffyhound]

The battery should never be connected when using mains adapter power so you don't need any diode there. The DC jack is switching and cuts out the battery connection when an adapter plug is inserted (if correctly wired).
Very rarely see chokes in designs here. Not saying it couldn't work, just why is nobody using them if there's some benefit.

[shovelhead138]

i thought the same.... thanks so much