tonebender mkII volume drop question

[daverdave]

Hey all, I recently made a friend a tonebender mkII, I used matched germanium transistors from smallbear and used a 20k trimmer to bias the 3rd tranny at -4.5V. When I was testing the circuit I wasn't getting unity gain with my guitar bridge pickup, which is a PAF pro, but was getting higher than unity gain wih the neck pickup, a stock japan mustang pickup. I figured that since this was happening it might be that the high output of the PAF pro was loading down the pedal, am I right in thinking this?

If this is the case, would using an input buffer solve the problem?

I also noticed that the volume increased when the 20k trimmer was increased, giving a higher bias to the 3rd transistor, although the sound did change at the top end of the trimmer.