Hi
The opa2107 is one of my favourite op amps , tonight though I listened to a opa2604 in a Pioneer PDS507 Legato Link Stable platter Cd player.
The opa2604 has a great way of following bass notes and rhythms, it also has very good bass accuracy but is not as open as the opa2107,
so you have to listen quite a while to pick up what it is good at.
The PDS507 was pretty easy to solder in a turned pin socket, its circuit board only taking a few minutes to invert to access the
original op amp position. Anyway what if we parallel a opa2604 with a opa2107 soldering one to the other , it would seem the best of both worlds was
then possible, -incredible detail from the opa2107 and really nice bass definition from the opa2604. and that's exactly what happened.
On some application notes op amp manufacturers recommend using low value resistors to share output loads where parallel op amps are used.
But the benefits of each op amp is easily heard, just with a direct parallel. To my ears a really nice relatively inexpensive upgrade that no usual
op amp rolling could even approach.