Our new paper Measuring carbon nanotube vibrations using a single-electron transistor as a fast linear amplifier is on the arxiv. Suspended nanotubes can be deflected by tiny forces, including the electrostatic force due to single electrons, but the deflection is difficult to track because the resonance frequency is so high: hundreds of MHz or more. In this paper, Yutian Wen and others describe our electrical circuit to measure this tiny and rapidly oscillating signal.