In general, Black Gates do better bypassed with BG's. The sound can get a little skewed with other capacitors, even really good ones. A .47 NPX 50V Black Gate would be good.
I also want to just let my E12 DIY burn in more as I still hear changes and the changes, in comparison to two other amps to confirm it is not in my head and so on and so forth, are positive so I want to know where the more-or-less stock amp ends up. I have also noted that Black Gates can take hundreds of hours to truly "form". This has also been noted by Audio Note UK, as they allow for many hundreds of hours before assuming the sound is final. They also feel BG's should have a charge to them all the time in order to stay formed or they will require some reforming again, and I have also noted this change.
I think I like the buf634 better. A little warmer, not warm but to me, the 5002 is very neutral but not as musical in this case.
Edited by jamato8 - 1/26/14 at 12:50pm