MOTM: Oktava ML52 (Spot the Difference)

I have a soft spot for Oktava microphones. They look cool, come from Russia, are fairly priced, and everyone has fun modifying them. That's enough to make the ML52 microphone of the month for June.

Oktava have a long tradition of ribbon microphones dating back (at least) to the ML11 in the 1950s. The ML52 is one of the most recent models, with a slightly odd double-ribbon motor assembly. I had some in to service recently, and noticed something odd....

Here are two ML52s - can you see any differences?

The answer is "Yes". The bottom mic has a logo and serial number, and an XLR that is machined into the bottom bell. It also has slotted screws rather than pozidrive. The grill spacing is also slightly different, but that is harder to see on the photos.

Under the grill, both have twin ribbons, but the motor assemblies are totally different. The one on the left is the same as the one found in Avantone microphones, the right hand one looks typically Russian, with silver contacts and big baffles to protect the ribbons.

The transformers are also very different. The right hand one is the mic with the logo, and it uses a toroidal transformer. The left hand transformer can looks typical of the China mics, and is connected to a (pointless) circuit board.

Sound-wise, the mics actually sound quite similar, which goes to show just how much the body and grill influence the sound of these mics. The Chinese one has a longer ribbon and stronger (neodynium) magnets, and has slightly stronger output.

Response plot for Russian (Red) and Chinese (Blue) ML52 mics

I don't want to say the word "fake", but  if forced to jump, the obvious conclusion would be that one mic is from the Oktava factory in Tula, Russia, and the other is made in China - either under license, or perhaps not.  :(