I know this topic isnt very tube specific, i hope it wont get moved or deleted.
I thought some tube users might be interested in knowing as well.
My plan or idea is to use Minidsp 2.1. Some may argue why would i want processing the signal before going to tube inputs? My intention is to use my fronts with sub. As you may already know the key is the integration between sub and the front. Unless some one have a lot of placement options, the phase in the sub is pretty much useless when sub is very near to the fronts. Delaying the front is the key. Thats why i chose minidsp, it has delay option parametic EQ, adjutable xovers and slope and is not very expensive, Im just not sure the compatabilty. i have heard that tube output impedance miss match with power amp may cause the high pass to have different cut off.