Just got Audible Illusions L1, but it sound harsh


I just got a Audible Illusions L1 preamp to replace my Rotel RC 1070. I can hear it is much more detail, it sounds more forward and bigger sound stage. But I also found it too harsh. Especially in vocal, the "s" sound is very loud and quite alloying. I don't have it in my RC 1070, but at the same time, it doesn't sound as musical. It is just like sing behind a curtain. I don't hear that detail, but also, those annoying "s" sound is "filter" out. Is it a characteristic of this preamp? Is there any thing I can do? I am using a Rotel RB 1080 amp. Should I try another preamp? Or try another amp?
gte357s
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Audible Illusions uses only a small number of electrolytic capacitors.  The large white ones are very expensive non-electrolytics.

 

You said you were playing a CD of a female voice and it sounded shrill in the low treble.  That is the sound of female vocals on major label CDs from the 80s and 90s.  Female vocals sounded terrible on CD but not on LP because the major companies were using crummy analogue-to-digital converters. Emmylou Harris was poorly served for example. Joni Mitchell's Dog Eat Dog sounded terrible too.

Try a jazz CD.