I would suggest to you that the threads you read are giving you false information. Most all the amps and preamps I have known or experienced that had both balanced and single-ended one could not use both simultaneously. Inputs or outputs. Hopefully one of the more learned will give us technical description of why and what the differences are?
BTW, Did you have to use the paddles to bring life back into the PSE? 
I just saw this. Sorry for the belated reply.
The PSE is making music, but I'm pretty disappointed at this point.
I ordered a matched pair of Valvo 7DJ8s from Brent Jesse. I opened it up, took some Deoxit D100 and F5 to the pots and switches, cleaned the tube sockets, and replaced the tubes. While the new tubes eliminated the crackling I was getting, the bass is just as bloated and the top end is just as rolled off as before. While I had the top off I looked around and all the caps looked ok--no bulging, corrosion, or signs of leakage. Two bypass caps had what looked like cellophane wrapping cracking and peeling a bit, but it just looked cosmetic. I did notice that it is a very well constructed piece of gear, and has aged well.
I'm about 10 minutes in with the new tubes, and the volume is still very low (need to turn the volume to the max to get to ~80 dB, which is louder than I usually listen, but not as loud as I sometimes listen. Last week when I first reinstalled the PSE the volume was also very low, but seemed to get progressively louder over a few days, so maybe it's a combination of caps charging and tubes warming up?
There is some midrange magic, although so far I liked the sound and musicality of the Oppo straight into the M60s much better.