Fake Oktava MK-319 pics

;ivlunsdystf · Post by **;ivlunsdystf** » Tue Feb 21, 2006 6:41 pm

Fair enough, I was out of line, sorry-

MichaelJoly · Post by **MichaelJoly** » Thu Feb 23, 2006 4:12 am

hey thanks, man. No problem.

Now I have to offer a correction. Last night I worked on a 319 that came in a hard plastic case not a a pouch (a sign of the earliest models), serial number N04621 but had the "fat" surface-screen-only logo. Opened it up, sure enough - all silver Russian caps and the early metal case FET. A Russian MK-319 for sure.

So now I have to eat crow about the fake logo news. I think what I've been seeing is naturally ocuring variations in the stamping/etching/screening process of the logos. Not a correlation between logo look and country of origin. Looks like parts branding is sill the the only way to distinquish country of origin. I apologise for the mis-information.

joelpatterson · Post by **joelpatterson** » Thu Feb 23, 2006 3:21 pm

A grateful world forgives you.

I guess I really lucked out, I have one of those miniature plastic suitcases too.

But I probably shouldn't have unscrewed the little screw to the center of the capsule to get the plastic shrouds off, huh, or at least I shouldn't have tightened it back on QUITE so hard and warped a little twist in the membrane of the diagphram. Unless that's a mod I just invented. Seems to still sound great, can you kill these things?

MichaelJoly · Post by **MichaelJoly** » Thu Feb 23, 2006 3:55 pm

Well, putting a screwdriver through a diaphragm when it slips out of a shallow-cut slot in a resonator screw will kill it. I have a little shrine of mic parts I accumulated from when I first started working on my own mics ten years ago.

If you think about it, the little spiral twist warp (been there, done that too) would tend to pull the diaphragm a little tighter. Perhaps careful measurments might show that the resonant frequency of the diaphragm had shifted up in frequency due to the higher tension. I've actually seen diaphragms come from the factory this way. A little too much vodka at break time I guess. But they still sounded fine. So I guess a little spiral twist is OK but these days I just snug the screw up enough to make contact and don't go any tighter.

eeldip · Post by **eeldip** » Thu Feb 23, 2006 4:22 pm

anyone have schematics?

MichaelJoly · Post by **MichaelJoly** » Thu Feb 23, 2006 6:40 pm

Here's one I scanned from an early 219 manual, it now lives on Mariks server:
http://home.comcast.net/~markfuksman/MK ... g_7__8.jpg

And in the thread below you'll find a nice clean one (319) drawn by Tim Harbin:
http://www.prodigy-pro.com/forum/viewtopic.php?t=487

eeldip · Post by **eeldip** » Thu Feb 23, 2006 6:57 pm

sweet, and someone scrawled in the values... supercool. here's mine:

joelpatterson · Post by **joelpatterson** » Thu Feb 23, 2006 7:09 pm

I see we have a family tradition going.

nlmd311 · Post by **nlmd311** » Thu Feb 23, 2006 7:15 pm

I chopped up my 219 also. I did it a few months ago and ended up coming right back to Atlanta and wasn't able to bring it with me. Didn't get to use it after cutting it up. Will get back to it next week and can't wait.
eeldip, did you do the same to the back? I left the backside of mine normal and only removed the front... curious to know if the back has that much of a sonic impact as well.? Maybe Michael could impart some knowledge on the thought?

-Darrill

eeldip wrote:sweet, and someone scrawled in the values... supercool. here's mine:

MichaelJoly · Post by **MichaelJoly** » Fri Feb 24, 2006 4:39 am

eeldip - The rough cut edges lend a certain dangerous "field improvisation" look to your MK-219. (I still love the name of this mic, its like a little weapon of sound). I use a fine dremel wheel, a couple of file grades, extra fine steel wool and super flat black paint to try and give my mods a factory fresh look.

re: front / back grille mod -

For the rear cancelation of the cardioid pattern to perform as intended, the front and back halves of the headbasket need to remain symetrical. This would mean the back half should be modified the same way as the front.

But, if we think about this for a minute, what might the differences be? Not modding the back allows the stock grille material to continue to function as resonant comb filters. This introduces very narrow band peaks and dips in the frequency response. So I would expect that the off-axis frequency response of a 219 modified this way would be a bit more irregular and its spatial response would become slightly more omindirectional at certain frequencies. This probalby would not be noticed in a close mic vocal situation in a quiet, well damped room.

I played with this front / back asymetry a bit in the past and am planning some extensive tests. I've converted a number of MK-219s to omni-directional pattern mics by removing the rear diaphragm and filling in the acoustical chambers with 5 minute epoxy. Makes a very nice room mic. My future experiments will involve tuning the polar plot of the mic by selectively filling in some of the acoustical chambers but not all. I expect I'll be able to create a modification that would be omnidirectional in either the low, mid, or high range. Close mic'd vocals will remain largely unchanged but the room pickup response will have a different timbre from a stock mic.

eeldip · Post by **eeldip** » Fri Feb 24, 2006 9:22 am

yea, i did the back the same as the front, i was figuring, its all about reflections and trying to minimize them.

michael, you ever try to raise the roof on this sucker.

the lack of uh. headroom, always seems scary to me.

MichaelJoly · Post by **MichaelJoly** » Fri Feb 24, 2006 10:11 am

Do you mean physical or circuit headroom?

eeldip · Post by **eeldip** » Fri Feb 24, 2006 10:27 am

MichaelJoly wrote:Do you mean physical or circuit headroom?

i was being cheeky.. i mean physical room. doesnt it seem crowded up there?

MichaelJoly · Post by **MichaelJoly** » Fri Feb 24, 2006 10:53 am

It is a pretty small headbasket, its shape and grille mesh sizing account for the small differenes in sound that remain between a modded 219 and 319. And its a sound I like btw.

The top portion of the mic case can be opened up by removing the extra fins and one layer of grille mesh. Or even cutting much of the top off and making a custom top grille. I've done this in some of my own mics. In my commercial work though I'm trying to offer the most bang for each buck of service time. So I routinely install a diffuser at the base of the capsule that helps disperse top-to-bottom reflections and lessens the need to open the top as a means of reducing reflections.

For those of us who obsess over diffractions and reflections in either mic transducer or speaker enclosures because they cause frequency domain coloration and time domain ringing, the thing to do would be to cut its head off and install an open grille.

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Fake Oktava MK-319 pics

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