How did you install T683 onto the arm stand?
Please follow the video below (from 0:15 to 1:16) to set up the microphone kit:
Screw the lower part of the C-clamp until it is tight and secure. Make sure that both the top of the C-clamp and the underside are resting on flat surfaces.
Place the bottom of the mic arm inside the C-clamp, then tighten the screw. Twist the shock mount and adjust the side that has a small round hole upward.
Put the microphone on a shock mount. Then take the threaded ring out from the accessories bag, then twist it on the microphone.
Pull the rubber band on the back side of the pop filter and put it on the mic to reduce pops. Three adjustable thumb screws give the flexibility of position.
What is the maximum thickness the clamp can handle?
The maximum thickness that the C-clamp can handle is 2.1". Also, note that you make sure that both the top of the C-clamp and the underside are resting on flat surfaces