My BHK arrives next week and I will burn in with the Tunsgram PCC 88 for 200 hrs as suggested by many others.
The BHK is fitted with 2 pairs of outputs and 10 pairs of inputs. Trading of 2 pairs of XLR inputs for another pair of XLR outputs would have been nice for me.
I triamp with my present tube pre amp which is fitted with 2 pairs of XLR.
One pair of XLR feeds a pair of active subs 25 feet away, and the other pair feeds 4 channels of amplification via passive crossovers 6 feet away.
I am planing to connect the BHK with the XLR feeding the subs and the RCA feeding the other 4 channels of amplification.
If someone else have done this kind of setup pls chime in.
I suggest feeding the sub with the SE outputs. The advantage of XLR is common mode noise rejection. While unlikely an issue for you in any event, any such noise is much more likely to be heard on your main speakers than the limited low frequencies the sub reproduces.
Another option is an XLR splitter. The BHK will easily drive both the sub and the other amplification.
Of course, the third option is the drive the sub with a signal from the amp if the sub provides for this.