I'm surprised that nobody has mentioned impedance :o
Guitars 'expect' to be working into a valve amp with an impedance in the region
of 1M ohm. Your audio card is likely to have an impedance of around 47k ohm.
This will make a significant difference to the behaviour of the controls on the
guitar itself.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.