MK47 PCB tube mic kit - build thread

[nashkato]

  I havent got others to try sadly harder to get in UK

you have seen those ?
  http://cgi.ebay.at/ws/eBayISAPI.dll?ViewItem&item=190401256090&ssPageName=STRK:MEWAX:IT

 

[Andy Meyer]

I tried swapping the capsule out with a capacitor and the popping continues.  At least I know it's not the capsule.

Any other ideas?

-Andy

 

[bruno2000]

Just finished building up one of these, but the output level seems really low.  Any ideas?  What mic should I compare it to as far as output level?
Thanks in advance!
Best,
Bruno2000

Problem was with transformer connections.  Both work great now.
Just FYI, the output seems to be a few dB hotter than a U87, but more natural sounding.
Best,
Bruno2000

 

[gary o]

Thanks Nashkato I may end up trying some....
Glad your sorted bruno2000

Andy here what I tried....sadly didnt work for me but maybe for you.....hope so

I burnt tubes in for 3 days , I thought i had solved it but no the pops came back...
My oil capacitor was getting warm & smells foul , I think it is leaking so I changed it for a modern cap
At one point sound went very thin turned out the small capacitor died , so i replaced that..
tried different capsules...
re soldered all joints...
cleaned tube pins & sockets
swapped tubes round
swapped last remaining capacitor as someone else had a problem with theirs

I need to get power supply checked a friend will help me....
After that il have to buy some tubes to try...

Good luck with yours, be interesting to hear how you get on.....

 

[Andy Meyer]

I am going to try replacing the 10nF cap.  When I tap on it I can get it to recreate the popping sound that I hear.  It's worth a shot at this point.

I can't imagine how frustrated you must be with all that you have tried.  I am hoping to get mine healthy soon.

-Andy

 

[gary o]

Thats sounds promising Andy as I said my 10nf totally died , think those caps are nos its also why I suspected my other caps....I kinda given up on the mic for now but I hope you can fix yours.

 

[mata_haze]

Hello Everybody,
I have built two of these amazing mics and they sound awesome...really incredible.
I have used Ioaudio psu (no regulators just the 5W pot) , beesneez capsule (awaiting substitution of one of the two due to diaphram being glued ...).
They worked at the first shot, the only problem is that when I switch for OMNI I get a loud crackle at the output (on both) and I have no idea what it could be due to.
yes its a crackle (like tube going). I am currently burning them in, they have been on for about 24h now but the noise is still there. they are absolutely fine in CARDIOID.

any ideas?

Mattia.

 

[gary o]

Switch .....could try removing it & hard wire omni.....

 

[mata_haze]

Gone,
I left the two microphones on for 48h and now they are as quite as a mouse...
nice!

thank you for the suggestion Gary o.

Best,
Mattia.

 

[AW_music]

This is our version of the PSU for this incredible MIC !!





Thanks to Mata _ HAze

 

[mata_haze]

this was a goooood project the mic sounds really really good!
thank you ioaudio for the kit, grand master for the case!
thank you aw_music for the FANTASTIC implementation !

YEAH!

Best,
Mattia.

 

[Denyle Guitars]

^Totally agree, this was a fun project. I'm still putting on the finishing touches but it passed the burn in and initial audio tests with flying colors.

psu

and mic

 

[kante1603]

Very well done!!

May I ask what type of resistors (the golden ones) you used?
I also like the idea of building the guiderails of hex metal-standoffs-cool!

Congrats,

Udo.

 

[Denyle Guitars]

Vishay resistors: http://www.mouser.com/catalog/specsheets/rhnh.pdf

Another shot of the mic, to be dubbed the "Stealth Pipe."

 

[ioaudio]

looks top!

 

[etiefenthaler]

Hi Denyle Guitars


Nice build !

I am interested in the carbon tube.
Did you make the carbon tube by yourself or where have you bought it?

Erich

 

[Denyle Guitars]

I found a 2 ft tube on ebay for $10. I was thinking how cool it would be to have a non resonant mic body, then I remembered freshman physics. 

 

[bobine]

My mic has recently begun crackling and popping while warming up and I remembered others here have had that happen. I'd been planning to open it up and remount the PCB so I finally got around to it tonight (I had hung the PCB from the rails with zip ties and wanted to try a more solid arrangement with angle brackets).

When I reassembled everything, the crackling was much, much worse.  I took the mic apart again and hung it up -- sans body -- and explored where it was most sensitive to interference...wow, even a wooden stick around the capsule wires will cause noise...

I noticed that the capsule wires would pass near the body tube when it was assembled so I rearranged them so they'd be well away from any surface. When I put the mic back together again, the crackling stopped a few seconds after it powered up and remained stable.

So I'm wondering if moving the capsules wires would help others with crackling problems. Tomorrow I'll try to deliberately induce crackling to see if the position of the capsule wires really is a factor.

 

[bobine]

I just noticed something strange: My MK47 with Beezneez K7 has an extremely narrow spike at 8165hz (and another at 16330hz). The 8K spike creates a lot of sibilance, though it's not hard to notch out. I noticed it on the Ozone 4 spectrum.

What could be causing this?  It also happens in omni mode. It's definitely the mic and nothing else in the chain. I looked at recordings from six months ago and it is there, too.

 

[gary o]

Bobine.... hi I have loads popping and cracking ,,,Im not gonna say mine has stopped BUT for now its has gone away after I sprayed switch cleaner over components & scrubbed with cotton bud......dont know if that cured it or if it disturbed something but for now at least its silent.....

I still cant record anything as next door decided to get a F**kin cockerel & it wont shut up .....Im off to buy a gun!

best of luck