Crystal Radio Amplifier

This may be a stupid question, but I'm about to build a crystal radio
(http://www.bobsdata.com/crystal_radio/index.html) and I want to use a
little audio amp (Cat. KC5152 @ www.jaycar.com.au), and was wondering
if I'd need the matching preamp (Cat. KC5172 @ Jaycar) for the crystal
radio's high impedance output. Any help on this appreciated.

Thanks,
Dave
.