Need recomendation for an IC to fill out and enrich the sound between amp and pre-amp.

Don't what level  to start looking for a quality IC compatible IC with a Conrad Johnson PV-14L pre-amp and a BAT amp to fill out the sound.  I opted for an all RCA pre-amp because I got a good deal on the CJ, and did not want to wait for a mixed BAT XLR and RCA pre-amp, or that of another brand.  I did a lot of looking over 4 months

So the advantage of lower noise using the XLR to XLR interconnect is no longer in play, and I am still using a Signal Audio Cable XLR to RCA to connect the amp to the pre-amp.  It cost about $59, not that price matters. It sounds good with the components, BUT, I think I can buy a much better  RCA to RCA  IC that will deliver a much fuller and richer sound.   As good as Signal Cable IC is, it seems to lack a fullness in the lower to middle midrange, and also the soundstage could be wider and deeper. 

I realize it could be the CJ pre-amp or the mix of CJ  which is 10 years old but was upgraded to the SE version Despite what I said, it sounds very good. 

Therefore, I would like recommendations for an interconnect that may accomplish what I described above before getting on "The Cable Company loaner library IC merry go round.  A  $200-$300 "USED" price range is my budget.   Thank you, SJ