WOW amazing awsome job on this detail review that you did. I love your review as an ex-X-Fi xtreme music owner. I currently use the Auzentech Meridian(or also known as Purity) 7.1 SC. This cards offers easy upgradable op-amps, a total of 4 - front, side surround, centre subwoofer, and back surround. The upgradable op-amps on them aren't required solder them in, it's just as easy, quickly and safely take them out with any mini sized flat (-) headed screw driver or with the proper chip remover tool recommanded from Auzen's support page.
Same with the OP, I also purchased my LM4562 from National Semiconductor but on their site I was redirected to Digi-Key. There is also DigiKey.ca so shipping from their warehouse in Ontario to BC only takes 2 days! Fast shipping.
The LM4562NA-POBD I use on the Meridian is 8-DIP size whereas on X-Fi it's SOIC.
Here's the long story short, I originally started with stock opamps on the Meridian which they're already preety decent. Then shortly after I switch the stock ones to Burr Brown OPA2134PA (recommanded from Auzen's support page) and sadly I hardly notice any difference despite many rave user reviews on them. Gladly I found the LM4562 in the forums and after the quick mod with them, I'm glad I was able to tell the difference right away. The sound is even cleaner, especially all instruments and each music notes are well seperated and defined. In the bass compartment, it's relatively better defined as well but not by a whole lot. Overall I'd say LM4562 op-amps are truely great and it's definetely a better upgrade over your stock SC's op-amps (NO placeable effect intended)
I've being wondering ever since the beginning I started doing op-amp mod and that's how will I be able to tell one of the op-amps goes faulty? As I mentioned earlier, there is one op-amp for each channel and a total of 4 opamps (front, side surround, centre subwoofer and rear surround) The front is also used for headphones, stated in the manual. So that's like I'm only using one of the 4 opamps (front output) is that right? And how will I know that the opamps are still performing at its optimal state?? Any comments are appreciated