Rhodes Chroma Polaris

I was checking out Youtube videos of the Polaris today and I came across this gem:

http://www.youtube.com/watch?v=TlXI0QBOAZw

Text in the video reveals that the owner replaced the last LM348 quad op amp (Z3 on the output board) with a TL048cn.  The end result is supposedly a punchier sound and more defined low end.  I did some more research and came across someone else saying to use a Burr Brown OPA2604 -- which is a dual op amp.

Anyone here attempted this mod or something like it? 

I'm contemplating using the 2604 since the TL048 appears to be obsolete and difficult to find.  If I were to use two 2604's then is it possible to tie the 12V supply for each chip together? (effectively making a quad op amp)