In the delta mixer applet, go to the third tab over (labeled hardware I think from memory)
In bottom right is a box for input sliders, open this section and lower the hardware input levels..
then go back to first tab and check the actual levels by scrolling to the right and looking at VU's

The hardware adjustment is for the actual preamp boost in the card (like a trim dial)

Then in the first tab there is an adjustment for the inputs that allow adjustment of how much of the trimmed signal gets 'sent' to the recording software. Have to scroll way to the right.
The first eight wave VU's are for the signal coming from the software (output).

I can post pics later if needed

Did you sync the two cards together to share a clock? This may be an important step

I do not work here, but the benefits are still awesome
Make your sound your own!