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TELEFUNKEN Acquires Stock of Rare AC-701K Vacuum Tubes

After a rigorous worldwide search, TELEFUNKEN Elektroakustik in South Windsor, Conn., has discovered and acquired a substantial stock of the rare AC-701K vacuum tube used in the legendary ELA M 251 microphone, which was originally designed by AKG and developed by TELEFUNKEN in the late 1950s. Presently, the ELA M 251 is the flagship model of TELEFUNKEN Elektroakustik, which manufactures faithful historic re-creations of the classic mics of the past.

“We are now able to replenish the stock for our most popular microphone, just in time for the holidays,” says company founder Toni Fishman. “These tubes are no longer made and they are commanding unheard-of prices. You might say it is one of the crown jewels of microphone tubes, and we were very fortunate to broker a deal with a quantity sufficient for more production. This may be the last run for quite a while.”

The rare AC-701K tube is a rather small triode vacuum tube that produces a very rich and opulent tone. Built with a glass enclosure, its characteristics include very low noise, a low degree of microphonics, and a propensity for an exceptionally long life, requiring minimal maintenance and consistent results.

“We have already tested and evaluated the tubes in our lab,” continues Fishman, “and they are in pristine condition. We are now working to produce a limited number of 251’s for this December and into January 2010. We are expecting to produce about 50 microphone systems for our dealer base and the public.”

The TELEFUNKEN Elektroakustik ELA M 251 features an edge-terminated, dual backplate capsule and the AC-701K tube, which was designed to meet the technical specifications of German and Austrian broadcast during the period when these microphones were originally constructed. The ELA M 251 system also comes with a Swiss-wound custom audio transformer, vintage style power supply, 10-meter Gotham Audio cable, locking leather bound flight case, wooden microphone box, owner’s manual, and a fully transferable warranty.

For more information about TELEFUNKEN Elektroakustik, visit