There are lots of comments in this thread about switching opamps. Both opamps you reference will work but the LM4562 is the one most commented on and generally given good reviews. If you use a dual opamp you are not going to get a BIG change but it can make an audible difference. If you want a significant step up try something like this:
Works for me and I went through a few duals before I found this. Now I don't feel the need for a change.
I've ordered the LM4562 to get a somewhat warm sound and a dual LT1364 to get a sort of neutral/bright-ish sound, that's all I wan for now.
It makes very little difference anyways and I don't wanna get into this too much.
Edited by conquerator2 - 1/15/14 at 4:06am