Adding a blend knob to a Vox 847

[AndreD]

I would like to add a blend feature to my Vox 847 wah to mix unaffected signal back into the output, with the pot having no effect when its dimed.  I've looked all over for something to do this and all I have found are buffer blend boxes, and my board is cramped as it is.  Anyone have a hot idea for me?