mk-219 mod

[ctdrac]

Hi Yall,
Been reading for years about people doing a mod on an Oktava MK 219, well my curiosity has gotten the better of me. I have had this mic for years and being such a "not pro" it has always sounded fine to me. Then I read an article a few months ago (this is where I get in trouble) how this mic has a capsule that copies Neumann but the poor body design and cheap components degrade the overall ability of this mic. Would love to hear if anyone has an opinion if the MK219 capsule really compares to a Neumann. I have ordered all the parts (I am doing the mod outlined by Scott Dorsey), cut out the "grill" and replace the screen, and added material to dampen the body. Dorsey's article says to use RTV to reduce the "ring" from the body, I used cork material to do this. I would have made a huge mess using RTV.
I am NOT an electronics guy so any words of wisdom on this would be appreciated. Photos are where I am at this time on the mod.

 

[Slouching Raymond]

I know little about microphones.
I wonder if that can with a tab is a solitary BC107 transistor.
Drawing a circuit diagram of what's there might be a good start.

 

[ctdrac]

This is the diagram from Scott Dorsey

 

[ctdrac]

Opps sorry, the "can" (I hope this is what you are referring to) will be replaced with a FET toshiba 2SK170BL.

 

[TalismanRich]

Hi Yall,

I am NOT an electronics guy so any words of wisdom on this would be appreciated.

Words of wisdom? ... stop reading the internet.

Hopefully you won't end up with a microphone that sounds like a Princess phone from 1965.

Call me a skeptic, but I read all the mic mod threads and without fail, they ALWAYS sound worlds better. Sweeter on the top, smooth as a a baby's butt, cuts through the mix, sounds better than that all original U-47. Maybe I'm completely deaf, but most of the comparisons show minimal difference (notice I didn't say improvement). If you're not an "electronics guy", how will you test your work. Can you solder competently? You're looking at replacing an FET, capacitors, resistors. BTW make sure you are modding the correct version. It's said there are 4 distinct versions of the MK219.

If I want a different sound in a mic, I just choose a different mic. Why take the chance of mucking up a perfectly good mic?

 

[Steenamaroo]

The most common mods I'm aware of for this microphone adding mass to the body to dampen the ring, as you mentioned,
removing the plastic rings on the capsule (non destructive), and replacing the grill material with something more open,
or just a single layer of what was already there.

I did all three many years ago. I very much like the sound of the microphones but were the mods worth it?
Honestly, it's hard to say. I didn't exactly do scientific tests or comparisons.

Certainly dampening the ring of the body seemed worthwhile.
Will cork be enough to make the difference?
I don't know but it'd be easy to hold by a plugged in cable and flick the body to see if it still rings or not.

Replacing the grills has to be done well.
I don't know what others recommend but I ended up setting them in place with a line of conductive paint, to ensure a good electrical connection all round.
There are probably other conductive glues/epoxies out there.
If you have gaps or weak connections between grill and body/frame, your mic will buzz like it's broken.

 

[Slouching Raymond]

I just had a look at Scott Dorsey's article at 'therecordingmag'.
What he says sounds plausable.
Mechanical padding of the case.
Increasing the impedance seen by the capsule.
Replacing resistors with more accurate 1% tolerance ones.
Replacing some caps with tantalum ones.
I'm not familiar with that FET.

Just not sure it will make any real difference to a mic that you already like.
If you proceed, you won't have the original to do an A/B test with.
He does describe that the replacement FET may have a different pinout to the original, so you may need to be electronics savvy.

 

[ctdrac]

Words of wisdom? ... stop reading the internet.

Hopefully you won't end up with a microphone that sounds like a Princess phone from 1965.

Call me a skeptic, but I read all the mic mod threads and without fail, they ALWAYS sound worlds better. Sweeter on the top, smooth as a a baby's butt, cuts through the mix, sounds better than that all original U-47. Maybe I'm completely deaf, but most of the comparisons show minimal difference (notice I didn't say improvement). If you're not an "electronics guy", how will you test your work. Can you solder competently? You're looking at replacing an FET, capacitors, resistors. BTW make sure you are modding the correct version. It's said there are 4 distinct versions of the MK219.

If I want a different sound in a mic, I just choose a different mic. Why take the chance of mucking up a perfectly good mic?

Had to laugh a little, I have had this mic for 9 years and never did the mod just for all the reasons you stated. I know, I know........ stop reading the internet. I have other mics and will be getting another stock MK219 soon. I think knowing I will be getting another one is the reason I decided to do the mod, more just out of curiosity. It will not be "scientific" data but after 9 years of using it I will be able to hear any difference (if there is any difference). IF things go south and I end up with a paperweight you will be the first to know, I will definitely give you the satisfaction of telling me "I told you so". What I meant by I am not an Electonics guy is that I do not do it for a living, I have basic knowledge and I'm very comfortable soldering.

Thanks for the "words of wisdom" you are probably right.

 

[ctdrac]

The most common mods I'm aware of for this microphone adding mass to the body to dampen the ring, as you mentioned,
removing the plastic rings on the capsule (non destructive), and replacing the grill material with something more open,
or just a single layer of what was already there.

I did all three many years ago. I very much like the sound of the microphones but were the mods worth it?
Honestly, it's hard to say. I didn't exactly do scientific tests or comparisons.

Certainly dampening the ring of the body seemed worthwhile.
Will cork be enough to make the difference?
I don't know but it'd be easy to hold by a plugged in cable and flick the body to see if it still rings or not.

Replacing the grills has to be done well.
I don't know what others recommend but I ended up setting them in place with a line of conductive paint, to ensure a good electrical connection all round.
There are probably other conductive glues/epoxies out there.
If you have gaps or weak connections between grill and body/frame, your mic will buzz like it's broken.

Thank you for the info about the gaps or weak connections between the screens and body. I should have included there is a layer of RTV behind the cork. I have not tested with the mic put together but there is more a thud than ring when I flicked on the two body halves. I should have all the parts I ordered within the next two weeks.

Thanks again

 

[ctdrac]

I just had a look at Scott Dorsey's article at 'therecordingmag'.
What he says sounds plausable.
Mechanical padding of the case.
Increasing the impedance seen by the capsule.
Replacing resistors with more accurate 1% tolerance ones.
Replacing some caps with tantalum ones.
I'm not familiar with that FET.

Just not sure it will make any real difference to a mic that you already like.
If you proceed, you won't have the original to do an A/B test with.
He does describe that the replacement FET may have a different pinout to the original, so you may need to be electronics savvy.

I do have resources (I know a guy that knows a guy, that knows a guy) if needed when replacing the FET, anyway, thank you (and the others) for the replies and info, got about 2 weeks before the parts come in, will let you know when they get here.

 

[Slouching Raymond]

One last word - Take good photos of how it is now, so you can backtrack if it doesn't work out.

 

[ctdrac]

One last word - Take good photos of how it is now, so you can backtrack if it doesn't work out.

Thank you, I will.

 

[TalismanRich]

Had to laugh a little, I have had this mic for 9 years and never did the mod just for all the reasons you stated. I know, I know........ stop reading the internet. I have other mics and will be getting another stock MK219 soon. I think knowing I will be getting another one is the reason I decided to do the mod, more just out of curiosity. It will not be "scientific" data but after 9 years of using it I will be able to hear any difference (if there is any difference). IF things go south and I end up with a paperweight you will be the first to know, I will definitely give you the satisfaction of telling me "I told you so". What I meant by I am not an Electonics guy is that I do not do it for a living, I have basic knowledge and I'm very comfortable soldering.

Thanks for the "words of wisdom" you are probably right.

That's at least a positive. I'm sure most of us have seen a bunch of "I don't know anything about electronics" and "I have never soldered before" posts. Sometimes it results in traces and pads lifting from the circuit board because of too much heat, and weak solder joints that don't make connections. Then often the next post is "why doesn't it work?".

I've done a few cap and resistor changes and I just don't hear the veils disappear and the heavenly lights shine afterwards. Nowadays, if I'm changing parts, it's for a repair, not for seeking sonic nirvana. Even that's become more rare. I've got a 60 yr old amp that needs new caps, and new tubes. When I worked up the BOM, it was the same or more than I originally paid for the amp in the mid 60s (the dang tubes are crazy expensive now). So it sits and I just use my other amps.

 

[rob aylestone]

Being ancient enough to remember the 219 and 309 mics when they first came out, at the time, both got good comments for sound, and the 219 was only slagged off for the poor castings and build quality. In the era of cold war Soviet engineering, they were made exactly in the way we imagined. Most people were very happy with them because the sound swung the popularity. I get the impression people are changing them because inside, cosmetically, they look almost home made. If I am reading the circuit changes correctly in the diagram, the components being changed are going to do things we would describe as equalisation. After the small changes they sound different. Surely this would have been done far simpler with modern EQ rather than a soldering iron. The circuit is so simple that nothing clever has been done, no changes to circuit function, no changes to the actual design. Swapping the transistor will change the gain, and the EQ too. Surely, the early plastic, crudely cut protection on the diaphragm had either a positive function, or a neutral one, or it would have been removed 40 years ago? It is inside, and invisible. Leave the poor mic alone. It is old, fragile, but perfectly functional. Break a winding on the transformer, and its dead forever.

 

[ctdrac]

Being ancient enough to remember the 219 and 309 mics when they first came out, at the time, both got good comments for sound, and the 219 was only slagged off for the poor castings and build quality. In the era of cold war Soviet engineering, they were made exactly in the way we imagined. Most people were very happy with them because the sound swung the popularity. I get the impression people are changing them because inside, cosmetically, they look almost home made. If I am reading the circuit changes correctly in the diagram, the components being changed are going to do things we would describe as equalisation. After the small changes they sound different. Surely this would have been done far simpler with modern EQ rather than a soldering iron. The circuit is so simple that nothing clever has been done, no changes to circuit function, no changes to the actual design. Swapping the transistor will change the gain, and the EQ too. Surely, the early plastic, crudely cut protection on the diaphragm had either a positive function, or a neutral one, or it would have been removed 40 years ago? It is inside, and invisible. Leave the poor mic alone. It is old, fragile, but perfectly functional. Break a winding on the transformer, and its dead forever.

I did the mechanical part of the modification, used it to mic up an acoustic guitar. Didn't record anything just listened through headphones and monitors, no effects and flat EQ. AND........wait for it......... to my ears it helped and cleaned up some of the muddy/muffled sound I had gotten before. Did it make the mic sound like a 9,000 dollar U-47? defiantly not but it did make me like the mic a little more. I have got a few weeks before the parts I ordered come in to try the mic other projects but even now I am thinking I will "leave the poor mic alone". Now what do I do with the 70 dollars of parts I ordered??

 

[Slouching Raymond]

I have parts totalling way more than $70 that I never used, going back 35 years. Such as an original 68000 processor.

 

[ctdrac]

I know you guys like pictures so here it is and will probably stay this way. After reading all the posts and hearing how it sounds now, I just don't think I will do anything else. Yeah Raymond, I am a pack rat, just can't let things go. Not saying you are a pack rat. lol