[tortugaranger]

I ordered a pair of Burr Brown OPA2134, I haven't opened up my preamp but is there one or two that need to be replaced?

Just one is needed. They are dual channel op amps.

[Hikmer]

Just one is needed. They are dual channel op amps.

I swapped out the op amp with the Brown Burr and gave it a listen, not critical but didn't hear anything that caused concern.  For the most part, swapping this out is like an adult version of Operation.  If your intent is to let people "roll" their own, perhaps a socket that is a little easier to use.  I've done this before with a Sutherland phono preamp and the sockets in that until had more user friendly opamp sockets. 

Waiting on a few other changes to my system to settle down before I give a critical review. 

[tortugaranger]

I swapped out the op amp with the Brown Burr and gave it a listen, not critical but didn't hear anything that caused concern.  For the most part, swapping this out is like an adult version of Operation.  If your intent is to let people "roll" their own, perhaps a socket that is a little easier to use.  I've done this before with a Sutherland phono preamp and the sockets in that until had more user friendly opamp sockets. 

Waiting on a few other changes to my system to settle down before I give a critical review.

Yes, the op amp is not exactly located where there's a lot of room - pulling out the 2 socketed gain modules on either side helps open up the access. As to the socket itself, the term "user friendly" and most any DIP socket do not go well together. That said, we do use a very high quality milled/machined socket made with BeCu - not a cheap socket. Doesn't mean it's easy - pins have to aligned just so - same as any DIP socket.