My nonpolar 1000uF blackgate will still take a few more weeks to be fully settled in but its been about a week now and it performs pretty consistent by now. The resulting sound combined with the 4562 opamp is *very* nice. The basses are very strong (try portishead's first album on this baby..) without being boomy, the highs are detailed and clear and the sound as a whole is quite pleasant. Fluid and natural of character (try norah jones, dido). It can definately *wow* you when good music is played at proper volume.
(observed over a pair of mordaunt-short speakers and sub, still eagerly waiting for my headphones to arrive, not in a A/B comparison so take it with some salt.. it sounded ok before but now its much more lively and dynamic, subjectively ofcourse..)
With these modifications the XFi becomes a very usable source component for music, which it isnt really in its factory form. Highly recommended!
According to cotdt it can even stand up to atleast the cheaper DACs, I havent tested this as I dont have a DAC (thank you, cotdt, i owe you a beer. you posted your mod at the perfect time for me
) nor feel like i need one at this point. The stock Xfi sound is really in a different league. So doubters, yes go find that iron and try this at home! Its really not that hard and you don't need soldering experience to pull this one off (insert standard disclaimer)
I'm not sure what the current opinion is on the 4 22uF capacitors near each opamp.. Is it clear what theyre there for yet and if they can safely be shorted in all setups (using amp, headphones directly in xfi, etc.)