Problem using Kaoss Pad for synths.

Okay, maybe this is rude, but TOTALLY ignore Musicaldude's solution, if you haven't already found out the ugly way. Boosting the signal that goes into the KP will just make the input LED light up red and you'll hear digital clipping [gross] and eventually hit a ceiling of all-crappy-staticy-noise and no real guitar left. Having it in the FX loop, and the Headphone-out workaround are smart moves already, except the Headphone out adds noticeable noise/hum vs the usual outs. But to help close the gap between your guitar's volume and the miniKP's internal synths (and program 63 and 65's feedback noizes, which build up even louder than the synths) unplug one of the RCA plugs from the KP's OUTput, pick one, left or right, whichever. You'll notice this gives you a guitar volume boost. BUT its still not enough...the synths and 63 and 65's feedback are still speaker-blowingly loud. Check the manual, it says you can adjust the wet/dry volume by holding down Tempo and Preset A together, then turning the knob and picking 1 thru 99. Make sure you're on the synth setting you want to use already. Do this thing. Play the synth with your finger, while you lower the number with that knob. Stay around 50 if you've got the one RCA plug dangling, around 20 if both are in. Whatever you think matches your usual playing volume. When its where you like it, hold the A or B button (wherever you want to save this) down and click Hold, this will save it onto that preset button. Now from now on, NEVER use 63, 65, or the synths if you're on whatever preset you DIDN'T just save. i.e. If you chose preset B, from now on you can just tap preset B and it remembers your volume adjustment from before, voila, normal-volume touchpad synth. But go back to preset A for every other effect, or you'll barely be able to hear the FX. KORG should've given us more preset buttons to save onto. Godspeed. I've never seen this site before, but I have this pedal, and experienced the same b.s. myself. Now I'm down to one preset button and quick knob-turning. Whee.

I imagine the internals synths are line level, which is really loud compared to what a guitar puts out.
You might need a pre-amp for the guitar into the KP to boost up the guitar signal. If you boosted the guitar up to line level (its way below unless you're using some kind of preamp), it's become louder as it is processed by the kaoss pad. i think the problem is that everything the kaoss pad puts out is at line level (e.g. the synth you're using) but your guitar input is nowhere near as high as line level, so synth is much higher.

Good luck,

The dude.