Nils Frahm uses a Helpinstill Piano Pickup, as seen in a Facebook post by Helpinstill Piano Sensor featuring a photo of the pickup on the soundboard. This model appears similar to the one used in several of his live performances, such as the one visible at the 18:21 mark in this YouTube video. While the exact model is unclear, the image suggests it may be the Model 280.

https://www.facebook.com/Helpinstill/photos/a.541022782706809/1343505265791886/?type=3&theater

"Seeing the Queen movie Bohemian Rhapsody last night brought back a flood of memories. Clearly visible on top of the grand piano in every concert scene is the blue and silver control box for the Helpinstill Piano Pickup used by virtually every rock act in the day. Although Queen was one of the few customers I never met in person, I still had quite an adventure with them! Late one night I was awakened by a phone call from their manager. He excitedly explained that, right in the middle of a dramatic moment at an arena rock concert, the piano feed just disappeared, leaving Freddie playing in silence to 20,000! He had traced the problem to the control box and needed another one before the next night. This was in 1976 and FedEx did not exist yet. He had selected a flight that would get a package to them by the a next day, and instructed me to get it to the Air Freight terminal. I had to get out of bed and drive to Intercontinental but we got it there. When we got the defective box back we discovered a crucial wire had been wrapped around a terminal but never soldered. It worked for years up until that fateful night."

I’m very excited by my new Helpinstill piano pick up. I’d been using an older model for the past few years which was great, but recently I used a newer model at a gig and the sound was incredible, so I have upgraded. For looping live the pick up is invaluable. It also enables me to get a really nice rich bass sound from the piano.