Intentional tone sucking

[Fleetdog]

I realized my Danecho delay is not true bypass the other day because when I turned it off, I still got a bit of a fuzzy quality to my tone.  I normally don't hear that and I haven't changed the battery in quite a while so I'm guessing this is caused by some sort of a buffer not getting enough juice.  I kind of like the effect if had and wouldn't mind building a box that just makes this sound so I could turn it on and off and adjust the fuzziness. 

Does my guess at what's happening seem reasonable?  Could this be as simple as setting up a unity gain opamp with the power being on a pot voltage divider? 

[aron]

I would do it with a single FET stage or Bipolar transistor instead of an op amp. Easier and (possibly ) more fun.