Anybody use a single ended component with one that is balanced?

Oh OK. Yes, just use the RCA (aka "single-ended") connection from the pre-out to the amp in. Don’t use the XLR outputs on the preamp until you have an amp with XLR inputs. You won’t get optimal sound by just using the jack adapters - or at least that is a possible risk.

BTW: I like the XLR adapters because they always connect ground first, so they can be swapped live.  I built a patch bay to switch between preamps and amps with neutrik jacks. Better than a HT bypass! 

@jji666

+1 Don’t add an adapter. If the amp is balanced it a;ready has one and is likely to be of higher quality. The manufacturer has a vested interest in making both inputs sound good.

Many people think XLR is better port. Do you think of Conrad Johnson pre and amp? They always use RCA port and so many people love this brand.

I might enter this brand some day if it works well with audio research power amplifier.

WORTH A TRY.

Sounds NOTICEABLY better between my Cary preamp and Pass amp.  I have compared the two options extensively and everything (sound stage, dynamics, transparency) sounds better.  

Return them if it doesn't work out.  

FYI here is my neutrik adapter using the XLR cable from preamp, in this case neutrik female to male RCA.  

In the OP's case he would use a female XLR to female RCA at the preamp.