Parasound A21

Hi Guys,

This is my first post so please accept my appologise for being not technical/ wrong!

I've a set up consisting of

CD Player Primare CD31
Speakers Paradigm S4
Parasound speaker stands
Subwoofer 2 x Rel T3
Preamp Parasound P3
Power amp Parasound A21
Belkin power purifier
Nordost Red Dawn interconnects XLR and RCA
Nordost Red Dawn biwire speaker cables

I'm pretty happy with my system but i still feel somehow it isn't completed! Hence, I've 2 questions which i'd like your advices/ comments on?

1. To me, the use of XLR on my system doesn't produce as good sound as RCA (interconnect between CD player and Preamp) due to RCA allows me to adjust the Treble and Bass on the Parasound P3. Will this story be completely opposite with say the Parasound JC2 preamp?

2. I'm tempting to obtain a used Parasound A21 to trial biamp or bridge mono setup. I do understand this is not a real biamp as i still have the passive cross overs in my speakers! (my gears are still under warranty). Hence, can you guys please give me some advices on whether i should biamp/ bridge mono? I love to have more of that airness sound come out of the speakers (not sure if i've explained correctly here!)

Thanking you all in advance for your advices
Tim