General guitar gadgets IC Buffer

[Tav]

Hi, I have built a guitar buffer, used this schematic http://www.generalguitargadgets.com/pdf/ggg_ic_buffer.pdf
If I place it before a volume pedal, like the Ernie Ball volume pedal, I get all sorts of scratchy sounds when moving the pedal up and down. That's not an issue with commmercial bufffers like the SKrydstrup or Axess Buffer.
The buffer also lowers the volume of my guitar, so it's not unity gain.
Someone else has experienced the same problem?

[Mark Hammer]

I think this is a build issue not a design issue.  A nearly identical circuit is used on countless commercial pedals, often with an attenuator pot after it, without problem.