Splitter blender for line level signals

[Yazoo]

I have a setup with a preamp and power amp, built from KMG's site. I want to use a Quadraverb with this setup and control the dry and wet signal balance. I breadboarded the Moosapotamos Paralooper but I get a lot of bass-heavy distortion when I connect this up, guitar and Quadraverb into Paralooper, then connected to preamp. Is this because I am mixing instrument and line-level signals?

Is it possible to use a splitter blender between the preamp and power amp and is there a schematic I can use please? I saw the Runoffgroove splitter/blender. would this do what I want?

[JFace]

Is the distortion coming from the split/blend circuit, or the reverb? First figure that out. Put the blend control to completely dry--if there is no distortion, it means you are overdriving the reverb effect. If it is distorting, you may need to increase your supply voltage and/or use rail to rail op amps.
What kind of input impedance is your power amp? If it is too low, the split/blend circuit may distort from driving too heavy of a load.

[Yazoo]

I found this modified version of the Paralooper and built it. It works very nicely and sits between the pre-amp and power amp. There is no noise and I can mix the wet and dry signals

http://groupdiy.com/index.php?topic=54947.0