Oktava MK102 microphone

[LevinGuitar]

The MK102 preamplifier seems quite the same as the MK012 with small differences.
The fet is 2SK170, the big electrolytics are all 33uf, the imput cap is 1nf MKT from Kemet. So it seems the famous old mods to 012 mics had some impact in the new preamplifier. The whole PCB is covered with some protective coating, but the print pinout on the PCB does not coincide with the real XLR connection.

But the best thing is of course the unique large diaphragm capsule with the smallest possible internal reflections head design. It sound great on instruments and voice. Yes, some EQ is necessary since the capsule is a K67 style. But overall it's a great mic as it is.

 

[McIrish]

They really got better with their PCBs. I have some old MK-012 mics that I did the mods on. The boards and components were nothing like the new ones. I imagine there is no longer a need to midify the preamp PCB anymore. Looks like they do all the upgrades now in-house.

 

[k brown]

The MK102 preamplifier seems quite the same as the MK012 with small differences.
The fet is 2SK170, the big electrolytics are all 33uf, the imput cap is 1nf MKT from Kemet. So it seems the famous old mods to 012 mics had some impact in the new preamplifier. The whole PCB is covered with some protective coating, but the print pinout on the PCB does not coincide with the real XLR connection.

But the best thing is of course the unique large diaphragm capsule with the smallest possible internal reflections head design. It sound great on instruments and voice. Yes, some EQ is necessary since the capsule is a K67 style. But overall it's a great mic as it is.

"XY Wide"?

XY is (and has always been), by definition a coincident technique; ANY space between capsules in the horizontal plane, and it's no longer XY, but "near coincident" (a broad category of arrays that include ORTF, NOS, DIN and EBS). Simply toeing-in the two mics doesn't make it 'XY', it's just 'toed-in' near coincident.

 

[LevinGuitar]

They really got better with their PCBs. I have some old MK-012 mics that I did the mods on. The boards and components were nothing like the new ones. I imagine there is no longer a need to midify the preamp PCB anymore. Looks like they do all the upgrades now in-house.

Well, C3 can be easily upgrade to a 1uf (or higher) mkt 50v. But I do agree that the pcb is well build.

 

[LevinGuitar]

Capsule disassembly is really easy

 

[emrr]

These are fantastic close tom mics, especially with the UP-012 preamp variation. Off axis bleed is very low, much lower than all the usual dynamic mics you see in that position.

 

[theholyweed]

I love these for the price!

 

[OneRoomStudio]

I have an AEG/Lomo K67, and I have found that it has much less of a presence peak than most K67s. It's a very nice sounding capsule.

 

[LevinGuitar]

I have an AEG/Lomo K67, and I have found that it has much less of a presence peak than most K67s. It's a very nice sounding capsule.

than most Chinese k67s?

I wonder if there is an easy way to tame just a bit the highs, like a cap from source to drain or so, but have no idea about it in this circuit. Maybe a small inductor before the output cap as the TLM103 / Behringer B1 have?

Also I,m tempted to cut a bit the low end, a smaller C3 or the imput cap value would do that?

 

[LevinGuitar]

I tried that ideas in an old 012 defective pcb (bad cap) and seems to work. Smaller C3 will cut low end and a 22uH inductor between C4 and 39R resistor seems to tame some high end (yet not sure what frecuencies and side effects).

Btw it's not easy to find a replacement for those output caps, max size must be 6x20mm. I tried bigger caps and a LDC body for the experiment.

 

[Khron]

Btw it's not easy to find a replacement for those output caps, max size must be 6x20mm.

What values can't be found in radial 6.3x11mm size? Solder in the negative lead, and bend the (longer) positive lead up along the cap body.

6.3x11mm can routinely accommodate 47u/63v.

Where there's a will, there's a way

 

[Gus]

than most Chinese k67s?

I wonder if there is an easy way to tame just a bit the highs, like a cap from source to drain or so, but have no idea about it in this circuit. Maybe a small inductor before the output cap as the TLM103 / Behringer B1 have?

Also I,m tempted to cut a bit the low end, a smaller C3 or the imput cap value would do that?

I posted a schematic to add a LPF when I searched for the thread I found the images are gone. IIRC people who built it liked it.

Here is one with something added you will need to trim the output resistor value marked as 39ohm for the best CMRR.

 

[LevinGuitar]

I read your old thread and saw you did some mod but without pics it wasn't clear for me.

Edit: now I see your pic, thank you, will try!

An update in that thread would be nice

 

[LevinGuitar]

I tried your lowpass mod (22nf) in the original MK102 and can't be more happier with the result. Maybe I could sell all the rest of my mics and keep this one
Thank you!!

Edit: The only thing that sound close is my modified Rode Broadcaster.