eBay and audio-gear-specialized platforms sell a lot of vintage or used microphones. Neumann is among the top selling brands. This is no surprise: handcrafted and built to last for decades, our hardware withstands the typical decline in value and this results in above average resale results.

 However, buying a used microphone entails several risks. Only a fraction of Neumann microphones are sent in for a regular service. So, the condition of this soon-to-be-your microphone might be undocumented. What are the key questions you should ask? What are important details that should be considered? We interviewed Medzid Veseli, our head of service and quality control. His team sees all our microphones from the late 40s to today on a regular basis. His insights:

“Has the microphone been used with a pop filter, reliably? This is not only about acoustics or plosives. A pop shield also protects the diaphragm from spit. And that shows, year after year. This contamination can accumulate to a point where it changes the acoustical properties a bit, a bit more, or a bit too much. From what we see in our service departments, pop filters are far less common than one might think. Or take sweat and how it tends to bloom out in the most sensitive areas of the capsule.”

“When you try to open our microphones, you will find the key screws in most of our models sealed with wax and an imprinted Neumann logo. Our technicians renew it after service. If this seal cannot be found or has been damaged, you might want to check why. Maybe it was serviced by a third party. If so, is there a service debriefing or an invoice? The capsule and its large high impedance areas are the most sensitive parts of our microphones. Smallest changes can quickly scale to parasitic effects in the signal chain. Something like a fingerprint would be a disaster, not to speak of dust particles.”

“We sell each of our models with a custom box. These boxes are carefully designed for a reason: they are free of plasticizers. Plasticizers can have effects on the tension of the diaphragm’s polyethylene foil. So, if the microphone has been stored in different cases or boxes, paddings with plasticizers are often used. Then you have a microphone stored in a hostile environment. That is why it’s worth checking if the microphone comes with its original case.”

“Neumann microphones are used all over the world and in various climate zones. While they can be operated in a wide range of temperatures and humidity levels, they should not be stored in these extremes. Best condition is a humidity of 0% to 90 % for microphones with double membrane capsules; 0% to 99% is best for miniature microphones. Look at the CV of the microphone: Has it been in regions with more extreme climate conditions? How was it stored there?”

“Older Neumann models might use a diaphragm with PVC-based foil. PE was invented later. PVC tends to harden over time. Original capsules would not sound as intended today. They need serious service. Double check this!”

“We get a lot of microphones before they are sold. Often, buyer and seller split the costs. We have varying standard procedures available worldwide: A quick status checkup, a basic service, or an additional certificate of authenticity, for example. This usually takes two to three weeks. Check our website for the service center in your region. It helps sellers to settle for a reasonable price and helps buyers to make an informed decision.”