The ELA M 250 and ELA M 251 are closely related microphones that were developed by AKG for Telefunken in the late 1950s. Both are based around the legendary CK12 dual-diaphragm capsule and share much of the same fundamental design. The primary difference between the two models is their available polar patterns.

• ELA M 250 — Cardioid and Omnidirectional
• ELA M 251 — Cardioid, Omnidirectional, and Figure-8

The additional Figure-8 pattern is the defining functional difference. The ELA M 250 provides two polar patterns, while the ELA M 251 adds the third pattern, giving the microphone greater flexibility for recording applications such as vocal duets, mid-side recording, room capture, and other stereo techniques.

Both microphones use the famous CK12 capsule.The ELA M 250 and 251 were derived from AKG's C12 design, but incorporated changes to the circuit, microphone body, head basket, and pattern-selection system. The pattern selector was moved from the external power supply, as used on the C12, to the microphone itself.

There is also an important distinction between the non-E and E versions of these microphones. The original ELA M 250 and ELA M 251 used the Telefunken AC701 tube, while the ELA M 250E and ELA M 251E were the export versions and used a 6072A tube, which was more readily available outside Europe.}

In practical terms, the relationship can be summarized as follows:

• ELA M 250 — CK12 capsule, Cardioid and Omni, AC701 tube in the original non-E version.
• ELA M 250E — CK12 capsule, Cardioid and Omni, 6072A tube.
• ELA M 251 — CK12 capsule, Cardioid, Omni, and Figure-8, AC701 tube in the original non-E version.
• ELA M 251E — CK12 capsule, Cardioid, Omni, and Figure-8, 6072A tube.

Although the ELA M 250 and ELA M 251 share many components and much of the same circuitry, they should not be thought of as completely identical microphones with a different switch. The headbasket, body, internal construction, and acoustic environment surrounding the capsule all contribute to the final sound.

For the BeesNeez BN251, the ELA M 251 configuration is particularly important because the microphone is designed around the three-pattern 251 concept. The additional Figure-8 pattern gives the BN251 greater versatility while retaining the characteristic CK12-based tonal approach associated with the ELA M 251.

If you only require Cardioid and Omni, the ELA M 250 concept provides everything you need. If you want the additional flexibility of Figure-8, the ELA M 251 is the more versatile design.