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The RFT CM 7156, is a high quality tube condenser microphone, made between 1956 and 1961, by the German Democratic Republic company Funkwerk Leipzig (which used to be the 'K├Ârting' radio factory before World War II ). Later all electronics companies in the GDR were forced to use the name VEB RFT (Volks Eigener Betrieb - People's Company, Radio and TV technique)
It was meant for studio recording and performance of vocals and instruments and was the successor of the model CM 7151, whitch had the familiar shape of the Neumann CMV 3 A 'bottle' microphone.
The CM 7156 has a mid sized Neumann capsule, the M07, based on the famous M 7 capsule, used in the Neumann U 47 and M 49. Just like the U 47, it had a directive pattern, switchable between directive and omni. Its nickname was 'Little Neumann' or 'Baby U 47' and it was definitely one of the very best GDR tube condensers ever made.

Inside it had an electronic circuit with two miniature tubes: a EC 92 and an AC 761, which was the GDR version of the famous Telefunken AC 701, the ultimate miniature tube that was used for some of the greatest microphones of all time: the Neumann M 49 / M 50 / KM 53/ KM 54/ KM 56 and the Schoeps M 221.

The CM 7156 was the only GDR microphone fitted with the AC 761 tube, which makes them extremely scarce, even more so than the Western AC 701 that fetches prices of $ 1000 on today's second hand market. The tubes were so small that the microphones could be miniaturized to the size of (the later made) FET transistor microphones.

My CM 7156 was lovingly brought back to life by Dutch tube microphone maker Bert Drost, of Gonzo Audio: he rebuilt the microphone completely, alas the original AC 761 was faulty and got replaced by another very good tube: a EC 1000, which is also used in (the earliest version of) Neumann's M 149. The result is a wonderful sound which comes very close to that of a U 47; one of the best ever made.

Although the shape and size of the CM 7156 is actually closer to the AKG C 12, also one of the most sought after models of all time. The C 12 had more different patterns, but the later Telefunken Eela M 250, derived from the C 12, was just switchable between cardioid and omni.

Some CM 7156 are still used in today's recording studios, their sound is often just as good as the best Neumanns.

This is one of the types that feature in my book Witnesses of Words. More information about that can be found at

wow cover


RFT CM 7156

Top: Front and back of the CM 7156 + sound

Middle: the Neumann M07 capsule and spec sheet

Bottom: CM7156 tube guarantee card and AC 761 tube

cm head
cm sheet
AC 761 tube