Preamp passive output vs a ht feature - signal degradation

For integration with a ht system is it better to run cables thru a passive output on line stage preamp or find a preamp with a ht pass thru feature? Or does it matter?

I have noticed that the signal from ht processor seems degraded as it passes thru a passive output on a preamp.  Lose alot of sound quality.  Stereo sq is very good but now ht sound going to mains is impaired.

Is there better treatment (preservation) of a signal when going thru a ht bypass feature on preamp?