i have a bb22x that i use occasionally. i bought it to play with my balanced inputs on my main power amp & behringer fbd in conjunction with my sub.
it is a passive transformer, so it really doesn't add any noise to the system. i have mainly been playing with my subwoofer channel, so i really can't tell you that it absolutely doesn't impact the sound quality of your output signal. but based upon my initial, non-critical listening, i don't think it will have any significant negative impact on sound quality.