In this video from Fearless Records, we see one of the bass guitarist of Pierce The Veil, Jaime Preciado, showing his touring rig. At this point in the video, he shows us his vintage Ampeg SVT AV Tube Bass Head.
If you pause at 2:59 really quickly, you will notice that Ben is using an anniversary edition of the Ampeg SVT-CL which is known as the SVT-AV. It looks like he changed some of the knobs and installed a custom grill cloth though. Phew...that was a tough one to find.