Fake Oktava update

[Audiopool]

I posted this in a recent thread on the subject, but I think it deserves an own thread.

We decided to get some empirical data for the Chinese made Oktavas, so we bought a pair from Thomann for measuring.

When opening the Chinese Oktavas we were very impressed with the nice and clean layout. Electronics look nicer than the original, that's for sure.
Also, it is obvious that the Chinese are very good at the machining. The looks are very impressive, like most mics from China.

The physical looks of the casing is very similar. But the actual solution for the assembly is different. The chinese screw the outer casing into a plastic part of the XLR contact, which might be a potential weakness. Otherwise I see no problem with the copy.
The capsule are interchangeable - the chinese capsule even fit on the russian micpres and vice versa.

We measured the cardioid and omni capsules only, since we did not have any original Oktava hypercardioid capsules.

Here are our results.

THE SENSITIVITY IS EXACTLY THE SAME
The difference between the chinese and the russian MC012's were around 0.5dB, which is within tolerance. The "Sound Patterns" comparison must have used the -10dB pad on their russian MC012. Or maybe they had a pad in the mixing board.
I am very surprised that they did not recignize this themselves.

Balancing
The balancing in the chinese Oktavas is not good. Actually the original Oktava design is 7-8 dB better to this respect. We noticed this when we accidentally had the cable connected to the chinese mic close to a transformer. This means of course thet the chines Oktava is more sensitive to noise and stuff being picked up by the cable. It will also have problems with unclean phantom powering.
Both the russian and the chinese version of the mic uses a "cheat balancing", however this works better in the russian design. The chinese has not taken care for correct dimensioning of the balancing resistor.

What about the frequency response?
They are very similar. The chinese MC012 rolls off quite steep at 15kHz, while the russian MC012 continues a bit further. This explains testimonys of the original MC012 as more "open" sounding.

The original MC012 also has better response in the deep bass. We could not measure this, since our setup does not admit correct measuring lower than 70-100 Hz. But it was noticeable when recording deep bass sound sources. I would say that this is the least important difference.

...and the self noise?
The self noise of the original design is a bit lower that that of the chinese copy. It is noticeable (which means that it is probably more than 1dB), but I would not say that it is a crucial difference when recording most sound sources.

Conclusion
The measurements gave pretty much the result that I expected. When I first tried these without any comparison ambition, I experienced the difference of self noise to be bigger.
The chinese Oktavas is a good microphone. It's not as good as the original, but it is far ahead of most other chinese mics that I have had my hands on.
Some of the flaws with the chinese Oktava design is fairly easy to correct, remaining would then be self noise and frequency response which in the end is closely connected with the capsule design.
In my opinion, the chinese MC012 should be priced more in line with the Behriger B-5, with which it shares many resembances. In this category it would be a bang for the buck, but with the current price tag, I would definitely go for a matched pair of original Oktavas.

We will publish frequency response curves and photos when we find some hosting. Hopefully quite soon.

[ahumphr]

Interesting (to me) to read some more quantified examination than I was able to manage. Thanks for this.

Just to pick up one point though ...

Originally Posted by Audiopool

The difference between the chinese and the russian MC012's were around 0.5dB, which is within tolerance. The "Sound Patterns" comparison must have used the -10dB pad on their russian MC012. Or maybe they had a pad in the mixing board.
I am very surprised that they did not recignize this themselves.

For the two pairs I had available, the chinese mics deliverd a significantly higher output on the same signal. I could only measure this by matching the meters on my pre-amp for the two mics monitoring the same 440Hz source, but they showed well over 6dB hotter output for the Chinese jobbies.

And, of course, there were no mic or mixer pads involved. Come on!

Who knows?? Oktava were well known for swapping for amp components Maybe my Russian 012s are lower gain than yours. Where did you source your real Oktavas?

Interesting that your tests show a steep roll off in the Chinese mics at 15K but not for the Russians. Examining the charts delivered with my Russians, there is a steep roll off at 15K.

Anyway, nice post, and I'm looking forward to seeing the charts.

Cheers
Aidan

[Audiopool]

I have EXTENSIVE experience with measuring MC012's. I have done this for a local Oktava distributor for some years now. I guess I personally have measured well over 50 pairs, and my colleague another 20 or so. The variations in output is NOT very big. Either you have a flawed pair of Oktavas or your chinese mics have too much (in my opinion) output.

Edit:

BTW, the typical roll off for the russian MC012 is at 17kHz and around 3dB roll-off until 20kHz. There IS a difference in this respect, but I personally think the balancing is the biggest drawback with the chinese. And of course the assembly - the screws anr only fastened in plastic. I believe that this is not a good design, and that it will not stand the wear and tear of a long lifetime.

Edit 2:

Are your sure your mixer output are calibrated? Or did you use the same output? Your preamps also shows nasty distorsion in some of the sound files. What kind of mixing board do you use?
At a scandinavian forum someone wrote that you padded the mixer whan you recorded the chinese Oktavas. This would indicate a too high output in your chinese Oktavas and this will be a problem when recording loud soundsources, since the mic does not ship with a pad.

Edit 3: Since the electronics are the same (apart from some strange values in the chinese mic) and the capsule design similar (although not the same, more about this any day soon. We are dissasembing the capsules now...), I have really a problem with accepting a much higher output even if your chinese Oktavas are defect. The layout is basically the same between the mics, the chinese use differents transistors, but these will NOT give a higher output. Actually the russian FET is, although not very quiet, very good. By changing to 2SK170 or whatever Dorsey used, the sesitivity will actually be .5-1dB less than with the original FET. And the self noise only gets 1dB less.
The only way to get more from this capsule would be to use a completely different design, maybe using transformer.

[Winey]

I just bought one of the new (no pad, rubber mic clip) Oktava's.
I'm bummed because the 10db pad is what makes my originals usable, since I solely use them on drums.
I haven't even heard my new Chinese MC012 mic yet, but I'm pretty bummed about the switch.
I had no idea.
I just though they finally made more at the original factory.
The new box should have been a giveaway.
Still a decent deal, but I'm still not very happy.
I love all my old MC012's with the pad and metal clip.
I'll have to give the new ones a test of my own.
Listening!

[Audiopool]

upping the thread