Pinose Amp As A Pre-amp? Options

[strangedogs]

Usually play my Guitar directly through my G5 Imac using a 1/4" --> 1/8" adapter on the end of my guitar cable... I'm using Amplitube and Guitar Rig software (Garageband too to import the tracks). Found a cheap Pignose Amp with pre-amp out and thought I could use it as a pre-amp to make the sound a bit richer - but the speaker on the Pignose doesn't cut out when used - is this normal? I can remove the speaker wires from the Pignose (internally) if I need to - does anyone know if this will work as a pre-amp??

http://www.pignoseamps.com/index.php?disp=...portamps&id=253