[bummrush]

from the Wyerd for sound site,, Exceptional Input Buffer raises input impedance to 100K ohms,as far as amps go in general what is the reason for this, and do other ice amps do the same?

[Gaara]

Some other icepower amps do this.  The reason for the higher impedance is so that they are easier to drive by the pre.

[sbrtoy]

Some preamps will have trouble driving low input impedances, in particular some tube ones.  The net effect of an impedance mismatch is usually weak bass and sometimes unpleasant midrange as well.