ORIGINAL: Philo

I did not desolder any wires, just moved them.

It's easy to tell--these are the ONLY two wires (I think green and black) that run directly from the mic cable jack to the output jack. I moved the wires up above the caps and as far away from the circuit board as they could go; I moved the white wire connected to the LED sideways so it was further away from the signal wires.

Of course, you should only do this with the AC cord UNPLUGGED so you don't have live power. There are unshielded points inside the PS with live 110 volts.

Philo

Yeah.. I did that stuff too when I was in there and that may be good enough, I'll try the shielded jumper and let you know if it helps.

Well, mine are working fine. I think if you get good continuity from the head shell all the way to the PS ground and on to the preamp through pin 1 the hum will go away.

Side note this experiment helped me a great deal, one of my AKG Solid Tube microphones had developed the exact same kind of hum and I didn't have a clue what was wrong. After working on the MKL2500s and discovering that case shield is the secret to fixing hum I did some testing and discovered pin 1 on the working Solid Tube shorted to the grill screen and the bad one it did not. All I had to do was take the mic apart and scrape the metal of the joint where the head and shell meet on the mic and it fixed it. Saved me a lot of money in repair cost. Paid for the two other mics that's for sure, I'm very happy and smarter.

ORIGINAL: 3MV

I am a bit dense. What do you mean by "replaceing the signal pins jumpers with a small section of shielded wire and also solder the shield to ground"? What is a signal pin jumper? Is there a specific wire color you are talking about? Specific wire location? Thanks in advance for any info.

What I mean is that the two wires inside the power supply that go from the 7 pin XLR to the 3 pin XLR pins 2 and 3 are the audio signal from the mic. They are just unshielded single wires. You could replace them with a small piece of shielded mic cable so even that small section would be shielded. And to make the shield effective solder it to that bare solid wire going to pin 1 of the 3 pin XLR (ground).
You can see them in this photo the audio signal wires are black and green and the ground wire is solid bare wire.

http://webpages.charter.net/coffeys/mkl2500psinside.jpg

It's not a project for you if you don't solder much it's a tight space and the mod is a long shot for doing any good.
Also in addition to the cable mod you can get a good mic case ground by using the case wire from the mic and making a jumper (small piece of wire) to solder it from pin 3 of the 7 pin XLR to the bare silver wire (ground). Again it's tight work and you have to remove the 7 pin XLR socket to get to pin 3 and that means making sure you have needle nose pliers to hold the nut to put the screw back. It's easy to find because it's the only terminal on the 7 pin socket that has no wire attached to it.

http://webpages.charter.net/coffeys/mkl2500psinsidepin3.jpg

Here is the pin out for the cable as far as I can tell. If you look at the connectors close you can see the tiny numbers for the pins.

mic power supply

1 ------- 1 Connects to wire on tube 126v
2 ------- 4 and 7 0 v ground goes all the way to capsule center
3 ------- 2 Goes through resistor to LED to tube 4.5v
4 ------- 5 Goes through transformer all the way to audio signal output XLR pin 3 -
5 ------- 6 Goes through transformer all the way to audio signal output XLR pin 2 +
6 ------- 3 Seems to go to transformer case and mic case inside mic but not connected inside PS !!

Again if you havn't done this kind of stuff and don't feel confident DON'T DO IT. it's dangerous !!! The cable shield mod and the switch flip should fix the hum problem, this stuff is just "nice to have". For the soldering iron geeks.

What you could do easy is scrape some paint off the power supply cover on the inside where one of the four screws go to hold it on and also on the base in the same spot. That way when you put it back together and tighten the screw you have metal to metal connecting the cover plate to the base.

ORIGINAL: vag0e

hello all...i too was allured by the 'black russian' as ive come to call it. of course the hum is there, blah blah, yadda yadda...so i have a serial number on the bottom of the mic, i opened it up just now and i discovered a PLASTIC disc beneath the capsule, much different from either picture ohhey or hotlungs posted...im wondering if this is all a game...im about to try plugging in the mic after having switched the 220/110 switch on the power supply with hopes of a cure for that hum. it seems like they used found objects to make these mics...but someone said that oktava had problems with manufacturing, could be several different stages of mics...interesting stuff.

thanks all for the posting, extremley helpful.

In addition to the voltage swtich you may need to do the shield mod. Either by the cable jumper or pin 3 (on the 7 pin XLR) to ground inside the power supply. Like I said in a previous post you can test to see if you need that fix by touching the little chrome spring loaded catch trigger to the case of the preamp or mixer where it can make good contact (not a painted part). If the bad hum goes away then you know you need to fix the cable. You will also noitce that if you push the catch down and let it spring back up the hum might cut in and out.

ORIGINAL: hottlungs

hey guys, i purchased a Russian MKL-2500 mic and PSU off my friend and returned one of my Russian/Chinese 2500 kits. The difference in quality of sound is unreal. I am also in the process of making some cables for these suckers. Pacific Radio in Los Angeles sells Mogami cable for $1.12 a foot and they also carry 6 pin and 7 pin neutrik connectors for $6.94 and $7.92 respectively(www.pacrad.com). With the Russian PSU there is no lingering hum after the cable mod, and i assume that after a complete cable switch, the quality will continue to get better. Keep in mind that i still have a Russian mic/Chinese PSU combo that I'm dealing with, so I'll look into trying to get the Chinese PSU hum free. Ohhey, if you figure something out let me know, and in the mean time I'll open up my Russian PSU and see how the Russians did their thing.

daniel daniel

Who did you deal with at pacrad ? I called the LA office and they said they don't stock the cable and the connectors were double the price you got.. gerrr...

By the way did you make new cables ? Did they improve anything with the sound ?

Heya Ohhey and the rest of you cool Techies!
It seems like I got sukkered with a russian/chinese mkl2500.
I am leaning to beleive that either they are russian and genuine or just FAKES from china.
My mic is exactly the same as yours. If it is possible that the mic IS Russian with the chinese PS, I feel Octava should be on "the HOOK" for this inmdescreptancy and replace the mic/PS with a genuine setup.
What the hell were they doing? BULK packing the mics separately?? I dont get it. This is a very STRANGE scenario that I feel Oktava is involved with. Guitar Center has a great reputation and I beleive they must have dealt with an authorized Oktava Dealer- its highly unlikely they would buy anything off the back of a truck thats for sure. So something really fishy is going on here. If I get time I am gonna call both Oktava and Guitar Center and **** because even for 99 Bucks its still a fake! It probably cost 5 dollars to make. Looks downright CHEAP to me on the inside and HUMS like a bastard and is unusable here. I am gonna hold off on any mods till I see what both Oktava and GC are willing to do.
Cheers and thats for the research. I would have never known it to be a fake!

I am curious and determined to see how Oktava will respond to this matter. I will keep you informed and also reference the conversations here as proof. Maybe if we all complain as a group effort , Oktava/GC will look after us to "save face"
Cheers and thanks again for the knowledge!

ORIGINAL: progdrums

UPDATE: The manager at GC in Rochester says they are no longer going to deal with Oktava and they are willing to refund my money and thats all they will do. I am gonna keep the mic, do the repair , and am still awaiting a response from oktava USA to see what the "truth" is.
Cheers

Ask them if they will repair the mic under warranty ?

OB BTW have you also seen this people?
http://oktava.tula.net/news/reliz_eng.htm

Both of mine have ASM on the back and no serial number at all.

Both of mine have ASM on the back and BOTH HAVE A SERIAL NUMBER under the twist off mounting ring.

Not mine.. I checked there. Very strange.

Indeed, I opened mine up and I think the mics are "REAL" and the power supplies and cables are Chinese. Inside my mics I found some cyrillic (sp?)(Russian) writing in pencil on the PC board. Also I think if these mics were made in China, the internal workmanship would be of higher quality...eg. better solder joints, metal work and threads machined better, plus the cap on all chinese mics that I have seen are of higher quality in the suspension system and mounting rings.

BTW, what does ASM mean anyway ??

Well bad news guys. According to Oktava anything NOT from russia is counterfeit. I am not surprised considering the real goes for 750 USD. Now that I have fixed my Chinese wanna-be Oktava I would like to somehow compare it to the REAL one. As for the workmanship being to shoddy to be chinese-keep in mind any NAME-BRAND condenser type chinese mics are made within 3 plants under strict regulation. These plants would not risk counterfeit racketeering type charges. The plant that made these mics isnt one of those :o(
I spoke with a guy at Oktava usa and he says the McKay brothers are crooks and forfeited an agreement with Oktava and counterfeited their mics...

I also soldered the wire inside the power supply from the "shunt" or ground of the XLR to one of the screws that bolt down the power supply.This worked for me.It should work for you too!
It makes the mic a very good deal as I think it sounds good after the repair.
Cheers and Merry XMas

Once more, guys: I think if you follow through on all the info on the Internet, this is what you will find:

1) Oktava in Russia = the real Oktava.
2) "Oktava" (McKay) in the UK was, for a time, an authorized distributor.
3) "Oktava"/McKay at some point lost that distributorship. Whether it was before or after they started commissioning the Chinese to do manufacturing, I don't recall.
4) "Oktava"/McKay seems to have had a larger supply of genuine Oktava mics than power supplies. Hence, some (but not all) of the Guitar Centre mics are apparently genuine, but have Chinese power supplies. Others are fake all the way around.

Beyond that, I wouldn't get too confident about the genuineness of the product, even if it has a serial number (unless you can confirm that serial # with Oktava Russia). After all, who's to say that "Oktava"/McKay and/or their Chinese manufacturer didn't figure out the missing serial number issue at some point?

Just thought I'd summarize this, since there still seems to be a fair amount of confusion.

Hi everyone,

I have been wanting this mic for a while and finally purchased it a few days ago. Unfortunately I didn't know about the fake mics, I read months ago that there were duds that came out of production but nothing about trademark violations. It makes me wonder how GC can get away with this without being partially liable. The guy at GC told me incorrectly that Oktava was moving their operations to China. After finding out about the fakes I wrote to Oktava USA and the guy called me and confirmed that all my mics were fine(I have ML-52's and a MK-012 too). He told me that they'd warranty the MLK-2500 if I purchase a power supply and cable from them for $300 and that it'd be a good deal since they normally sell for $900(they sell at list!). I am not going to do that though, I got the 2 year at GC for $20 with the mic and I'd rather mod the existing PS. I mean $300 for a transformer and a few parts in a metal box is outrageous!

Does anyone have the schematic and parts list for the Real PS? I haven't had a chance to try it out and hear the hum, but in addition to the hum I am real concerned about the tube being properly powered. I read a prior entry that said something about the Real PS having more power going to the tubes. From my understanding, a typical tube has 6.5 volts at the heater and several hundred at the plates.

Thanks and take it easy,
Jason