Hmm kan det ha att göra med att den ena använder semipro-nivåer och den andre pro-nivåer.
Jag citerar lite från http://www.outersound.com/osu/recording/recglossary.html
The real story on line levels is fairly complex, but the quick answer is:
* -10dB level is about 0.3 volts
* + 4dB level is about 1.2 volts
Pro levels are +4, semi-pro and consumer are -10. The original US telephone company signal levels became today's +4; the Japanese consumer-electronics industry began a -10 standard.
Without going into all the impedance and stuff like that, either level is fine, but +4dB lines generally have better noise immunity because the signal level is much hotter. As long as your -10 equipment can handle the higher input level you'll be fine. Prevent overloading it by keeping its input-level set low.