Stock vs. Modified Oktava MK-012s mp3s

[ecs113]

Done? Did you modify yours?

yes - I performed the modification written in Recording Mag Sept 2003 by Scott Dorsey. I didn't perform any scientific testing, but I did play an acoustic guitar through the mic before and after.

 

[Flatpicker]

yes - I performed the modification written in Recording Mag Sept 2003 by Scott Dorsey. I didn't perform any scientific testing, but I did play an acoustic guitar through the mic before and after.

That's basically all I did. I just tried a few different caps along the way.

 

[ecs113]

I am very pleased. I also modded 2 mk219's and an MCA SP1, all with positive results. I am finally tackling a backlog of repairs/modifications, and really enjoy it.

 

[Flatpicker]

I am very pleased. I also modded 2 mk219's and an MCA SP1, all with positive results. I am finally tackling a backlog of repairs/modifications, and really enjoy it.

Very cool!

What did you do to the 291's?

 

[ecs113]

Very cool!

What did you do to the 291's?

quite a bit

originally experimented with mechanically modifying them:

-removed mechanical high frequency exciter (that circular disc on the diapraghm)
-removed outer-grill on the front to cut down on chamber resonance
-put speaker putty on the floor of the chamber to cut down on internal reflections

greatly helped out, although a bit dark

got some parts together today and tackled upgrading some components:
-replaced what were supposed to be 2x 680M ohm resistors, which were actually small capacitors, with 2x 1000M ohm resistors
-replaced the FET(?) with a 2sk170BL
- replaced the dielectrics

I did my 2 mk219's today, plus the Dorsey mk012 mod, which was a bit trickier

 

[JCALAB]

Oktava Mods

Flat Picker..
Your posts on Modifying the Oktava mics I found interesting.
I have 2 MK 219's and find them to have an " acceptable " response for the work I do " Home Recording ". But, If I can get significantly more out of them through modification rather than spending hundreds more on more expensive mics, I may be interested in doing the same. I use them mostly for acoustic guitars and mandolins. I have an AT 4040 for vocals that I'm very pleased with. Can you provide some more info ?
Thanks in advance,
JC

 

[deharmonic]

quite a bit

originally experimented with mechanically modifying them:

-removed mechanical high frequency exciter (that circular disc on the diapraghm)
-removed outer-grill on the front to cut down on chamber resonance
-put speaker putty on the floor of the chamber to cut down on internal reflections

greatly helped out, although a bit dark

got some parts together today and tackled upgrading some components:
-replaced what were supposed to be 2x 680M ohm resistors, which were actually small capacitors, with 2x 1000M ohm resistors
-replaced the FET(?) with a 2sk170BL
- replaced the dielectrics

I did my 2 mk219's today, plus the Dorsey mk012 mod, which was a bit trickier

that should read "replaced electrolytics"

ps - ecs113 is now deharmonic

 

[Flatpicker]

Re: Oktava Mods

Flat Picker..
Your posts on Modifying the Oktava mics I found interesting.
I have 2 MK 219's and find them to have an " acceptable " response for the work I do " Home Recording ". But, If I can get significantly more out of them through modification rather than spending hundreds more on more expensive mics, I may be interested in doing the same. I use them mostly for acoustic guitars and mandolins. I have an AT 4040 for vocals that I'm very pleased with. Can you provide some more info ?
Thanks in advance,
JC

The 219s are like 319s inside, and I’ve made a lot of changes to my 319, but I’m still not satisfied with it. Basically there’s a 680pf between the capsule and the FET, and a 1uF/160V electrolytic between the FET and the transformer that needs to be improved. Try changing the 1uF/160V to a good 1uf metalized polyester like the Panasonic V series (Digikey) and a 820pF COG ceramic in place of the cheap 680pF ceramic. Gus likes to put a 1000pF polystyrene here, but I haven’t had time to try it yet. You have to buy the polystyrenes from Mouser. BTW, the 1uF ele doesn’t need to be 160V and I don’t know why they put caps with voltage ratings that high in there. 25V should do just fine.

For guitar and mandolin, I'd get a MK012 and modify it.

 

[Flatpicker]

...removed mechanical high frequency exciter (that circular disc on the diapraghm)...greatly helped out, although a bit dark

Mine was dark too, so I put the disc back on - sounds better with it on to me.

...replaced what were supposed to be 2x 680M ohm resistors, which were actually small capacitors, with 2x 1000M ohm resistors...

Those are resistors - they just look like caps.

...replaced the FET(?) with a 2sk170BL...

When I did this, it lost a lot of the full sound I heard with the old FET, so I put the old one back in. Gus suggested going with the 2SK170 and tweaking the bias some, but I haven't got around to doing that either. Oh well, it'll be a good project on a rainy day this spring when my wife can't make me go out and work in the yard.

How did the MK012s turn out?

 

[Marik]

Hey Flatpicker,

Today somebody brought a couple Oktavas to upgrade. I run out of BGs and Wimas and went to local electronic store. Look what I found there. It's about 3mm thick. You remember I told you about BG instead of 1Mf cap? Forget it. Monday I am going there to buy the whole stock

PS. Yeah, please don't mind the flux on the right side--it is a stock one. I haven't touched yet there. BGs on the way!

 

[Flatpicker]

Hey Flatpicker,

Today somebody brought a couple Oktavas to upgrade. I run out of BGs and Wimas and went to local electronic store. Look what I found there. It's about 3mm thick. You remember I told you about BG instead of 1Mf cap? Forget it. Monday I am going there to buy the whole stock

PS. Yeah, please don't mind the flux on the right side--it is a stock one. I haven't touched yet there. BGs on the way!

Ooooohhhh baby! A ferfect fit! How does it sound?

 

[Gus]

3 uf film cap nice. I have fit 1uf PET films in 012s

 

[Marik]

<How does it sound?>

It sounds..... good. More relaxed, open and transparent than electrolitics. Both, bass and top improved--everything more defined.
I was asking the guys in the store what's the part number, and who's manufacturer, but they even don't know how it got there... he, he. It is quite a funky store, I have to go fishing there. Oh yeah, I also found there some Vishay axial resistors--good stuff.

 

[Flatpicker]

<How does it sound?>

It sounds..... good. More relaxed, open and transparent than electrolitics. Both, bass and top improved--everything more defined.
I was asking the guys in the store what's the part number, and who's manufacturer, but they even don't know how it got there... he, he. It is quite a funky store, I have to go fishing there. Oh yeah, I also found there some Vishay axial resistors--good stuff.

Cool. If you decide you can spare a couple, I'll buy them off of you.

 

[Marik]

<Cool. If you decide you can spare a couple, I'll buy them off of you.>

I have a better idea... How about if I make a CD with modified and unmodified ECM8000 comparisons and send it to you along with a few caps? In exchange, you'll make and post the MP3 clips, so folks here could hear it.

 

[Flatpicker]

<Cool. If you decide you can spare a couple, I'll buy them off of you.>

I have a better idea... How about if I make a CD with modified and unmodified ECM8000 comparisons and send it to you along with a few caps? In exchange, you'll make and post the MP3 clips, so folks here could hear it.

You drive a haaarrrrrrd bargin, Marik. Let me think about this...Ok, it's a deal!
Check your PM.
(I'd still be more than happy to pay for the caps!)

 

[ausrock]

I just hope when you guys have finished all this that you will re-post it in a form that can be understood by the less technically minded.

For starters, clear desciriptions of alternative parts would help. As it stands, if I want to find that cap that looks like a mini soapbar, I'll probably have to take a photo to my local supplier so he knows WTF I'm talking about .

 

[ausrock]

BTW, FP....................I haven't forgotten the Tommy Emanuel CD's. Actually I saw he and his brother on TV last night performing at the Aust., Country Music Awards, as usual....bloody awesome!

 

[Flatpicker]

BTW, FP....................I haven't forgotten the Tommy Emanuel CD's. Actually I saw he and his brother on TV last night performing at the Aust., Country Music Awards, as usual....bloody awesome!

You know, I thought about that today for the first time since we spoke. Don't know why - it just popped into my head. I wasn't going to rag you about it, though. If you get time, that'd be great, but no hurry.

Yeah, his brother's incredible too. I'd sure like to hear him play again!

 

[Flatpicker]

I just hope when you guys have finished all this that you will re-post it in a form that can be understood by the less technically minded.

For starters, clear desciriptions of alternative parts would help. As it stands, if I want to find that cap that looks like a mini soapbar, I'll probably have to take a photo to my local supplier so he knows WTF I'm talking about .

I'd be glad too when I get a minute. My hands/wrist have been cramping up on me lately too, so it's difficult to type a lot.

(edited because I was beginner to sound like a whinner)