OK, now you have a choice: stay with the default gains, or install the missing components to increase the gain.

Also, make sure you are comfortable with soldering components this tiny. If in doubt, practice on an old motherboard with 0603 components before wielding your soldering iron.

Do not simply wire the output audio connectors to the 4 zero ohm resistors! There is a 6V DC bias on these signals, and you MUST provide AC coupling. The components shown here for each of the 4 channels are:

10uF, 50V NP (Non-polarized) Aluminum Electrolytic capacitor

300 ohm, 1/4W resistor

Three different views are shown. Note the piece of 16GA copper wire which is looped around the mounting screw (screw is removed in the image). This point is analog ground, and the screw provides support for the little round PCB (this is a Radio Shack special; isn't it cute?). The shields of the audio coax also solder to this wire.

Note that the long leads of the NP caps are soldered directly to the newly installed components; be careful doing this! You don't want to get one lead soldered, and then wedge the whole assembly sideways, or the components will be damaged.

If you elect not to install the missing components, solder the cap wires to the 4 zero ohm resistors, instead of the components shown here.