Hi Artemus, wish I could help more. As Dekay, I never used this in my system. Sonically, the mid-range darkened only by a tad, the bass was boosted and the highs became more pronounced and a bit harder -- but at least, one got a simulation of highs... I remember (may be wrong on this) the x-tone being connected between source component & line input; this setup may sound better than going thru the tape-loop.
Not much to go on, I'm afraid.
But, do play around with your adcom, as bruce & dekay suggest, it may offer an acceptable solution.