This mic has been recently, last 30 days, refurbished by the world renowned Tom Onofrio. formerly a factory authorized Sennheiser/Neumann technician for over 20 years as a microphone etch.

This Neumann U87 Ai has a new K870 capsule, rebiased FET, new wiring, solder joints, and grounding represents a significant refurbishment and upgrade of this iconic studio microphone. The K870 is a version of Neumann's K67 capsule, which is a large-diaphragm, dual-backplate design known for its detailed and transparent sound12. The rebiased FET (Field-Effect Transistor) suggests that the microphone's electronic circuitry has been adjusted to optimize its performance, potentially improving the microphone's sensitivity and noise performance16.New wiring and solder joints indicate that the microphone's internal connections have been renewed, which can help to ensure reliable signal transmission and reduce the potential for noise caused by poor connections. Grounding improvements are also important for minimizing hum and radio frequency interference, which can compromise the audio quality.