Question How can I connect the Sentry Noise Gate in the (serial) FX loop of my guitar amp  Answer
  1. Connect the guitar into the Sentry pedal IN - 
  2. Connect the pedal Send to the amp input - (there could be a chain of other distortion or drive pedals before the amp input) 
  3. Connect the amp FX loop send into the pedal return 
  4. Connect the pedal OUT into the amp FX return - (you can also connect modulation, delay and reverb pedals between the Sentry OUT and the amp FX return).