Warm Audio WA-CX24

Unlike the original C24, the WA‑CX24’s rotation system has markings to help you set the correct angle.

Warm Audio escalate their mission to make vintage gear affordable with a recreation of a classic stereo mic.

Iconic stereo valve mics are like buses. You wait years for a modern‑day reproduction of one — and then three come along at once.

In May this year, I reviewed Vanguard Audio’s V24, which attempts to capture the strengths of AKG’s immortal C24 whilst correcting some of its perceived weaknesses. Announced at January’s NAMM Show but yet to reach SOS Towers, the Peluso P24 is described as a “tribute to the legendary AKG C24”. And now Warm Audio have pitched in with the WA‑CX24, “engineered as a faithful recreation of one of the most sought‑after stereo microphones in recording history”.

Quite how many people have been standing at the bus stop waiting for the number 24 from Vienna is debatable, but it’s clearly having a bit of a moment. And if you’re struggling to decide which vehicle to run for, the cost of the fares definitely favours Warm Audio. Whereas the P24 retails at $3999£3999, and the V24 costs more than twice as much, the WA‑CX24 is extremely keenly priced at £1449$1599.

24 Carat Brass

The AKG C24 is sometimes described as a stereo version of the better‑known C12, and does indeed have much in common with that mic. It uses the same valve, the same output transformers and, most importantly, the same ‘brass ring’ CK12 capsules that are also found in the Telefunken ELA M 251 and in early AKG C414 models. One reason why the prices of vintage AKG mics have remained so high is that these capsules have proven uniquely resistant to mass production. AKG themselves made them by hand, with a scary rejection rate, and eventually ditched it in favour of the cheaper and more amenable ‘nylon ring’ version. Even today, the Far Eastern plants that churn out accurate copies of Neumann K47 and K67 capsules still can’t do the same with the CK12.

The design of the C24 permitted a mutual angle of up to 180 degrees to be obtained by rotating the upper capsule, and rotary switches either on the PSU or a separate controller offered nine polar patterns for each capsule. It was thus possible to use a C24 for Blumlein stereo recording, with both capsules set to figure‑8 and angled at 90 degrees, but that was only the start of it. Many variations on crossed cardioid and hypercardioid could be created by varying the pattern and the mutual angle, and it could also be configured as a Mid‑Sides array; indeed, the stand adaptor offered dedicated settings for X‑Y and M‑S use.

Supersize C

In its ’60s heyday, the C24 wasn’t only employed in recording studios. Radio and TV also needed high‑quality stereo mics, and with the latter in mind, AKG’s designers worked hard to make their offering as compact as possible. The C24’s narrow cylindrical body is filled to bursting with circuitry, and the 6072 valve occupies a cut‑out in the middle of the back‑to‑back printed circuit boards that handle the signal from each capsule. Although they are small, the two Haufe T14/1 transformers barely fit inside.

Makers of modern C24‑alikes have less reason to worry about their mics being visually obtrusive, so tend to opt for more generous dimensions and a less crowded interior. Even so, I was unprepared for the sheer scale of the Warm Audio WA‑CX24. It’s gigantic: by some distance the largest capacitor microphone I’ve ever seen or used, and much larger than either the original C24 or the Vanguard V24. More precisely, it measures 356 x 51mm to the original’s 255 x 43mm, which by my calculations equates to almost double the...