MK47 PCB tube mic kit - build thread

[rrowley]

Yes,and the relays contacts are open in cardioid and closed in omni
Rich

 

[bobine]

Hi All
The problem I have is that in cardioid both front and back of the capsule are on,although the back is duller sounding.If I switch to omni the sound becomes quieter and really thin sounding,again both front and back are on.

With mine (same setup), in cardioid, the sound from the front is good (uh, great) and the sound from the back is not good (kind of ugly sounding; certainly duller.) In omni, the overall level is lower and the sound is different, less vivid (partly because it is quieter, partly because there is more room in the sound.) I wouldn't say it is "really thin" but I could understand saying it sounds thinner compared to cardioid.

I can't tell for sure, but it sounds like your mic is behaving like mine is. It sounds so amazing in cardioid that I haven't questioned the rest.

 

[Sredna]

Sorry for asking such a question, but are you two familiar with how cardioid and omni works?

Just trying to clear out misunderstandings....

 

[gemini86]

in cardioid your back diaphragm is disconnected, off. So you're still listening to the front diaphragm, even though you're yelling at the back of it's head.

 

[The Frizzle]

Do you think it would fit in this case?:
http://www.musik-service.de/mxl-550--551-set-prx395772760de.aspx
Its just 89€ which is like 127$.
But maybe this one is even too cheap and has plastik parts or something?
I like the look tho.

 

[pasarski]

Hi All
The problem I have is that in cardioid both front and back of the capsule are on,although the back is duller sounding.If I switch to omni the sound becomes quieter and really thin sounding,again both front and back are on.

With mine (same setup), in cardioid, the sound from the front is good (uh, great) and the sound from the back is not good (kind of ugly sounding; certainly duller.) In omni, the overall level is lower and the sound is different, less vivid (partly because it is quieter, partly because there is more room in the sound.) I wouldn't say it is "really thin" but I could understand saying it sounds thinner compared to cardioid.

I can't tell for sure, but it sounds like your mic is behaving like mine is. It sounds so amazing in cardioid that I haven't questioned the rest.

Cardioid pattern is directional. It never sounds good on other side. In omni position there is no proximity effect and the mic will sound relatively thinner compared to cardioid at close distance. Farer away, say one meter or so, there shouldn't be so big difference in frequency response.

 

[duy_hoang]

Do you think it would fit in this case?:
http://www.musik-service.de/mxl-550--551-set-prx395772760de.aspx
Its just 89€ which is like 127$.
But maybe this one is even too cheap and has plastik parts or something?
I like the look tho.

(I think) this one is better :
http://www.thomann.de/de/thon_flex_cut_universal_mischpult_1.htm

 

[The Frizzle]

thanks duy_hoang, right your case looks better.
But actually i was thinking of mounting the MK47 inside of the MXL 550 body
I'm just not sure if it will fit.

 

[rrowley]

in cardioid your back diaphragm is disconnected, off. So you're still listening to the front diaphragm, even though you're yelling at the back of it's head.

problem is the back seems to be on in cardioid.Is everyone else seeing a 17v drop when omni is engaged?
Cheers
Rich

 

[0dbfs]

thanks duy_hoang, right your case looks better.
But actually i was thinking of mounting the MK47 inside of the MXL 550 body
I'm just not sure if it will fit.

MXL 550 Looks to be slightly too narrow at 47mm x 170mm (according to the PDF on their website anyway) but maybe you could file down half a mm around edges of the mk47 PCB? If you pick one up please let us know whether your mk47 PCB's will fit with room for everything. I saw some of the 550/551's advertised for $79/pair. Maybe you could also make a PCB that fits inside this body and still have the SDC for some franken-mic'ing action.

[quote author=The ioaudio]
Title: Re: MK47 assembly - more pics added
Post by: ioaudio on November 12, 2010, 02:12:53 pm
A 50x1mm (inner dia. 48mm) is the absolute minimum.
[/quote]

Cheers,
jb

 

[Sredna]

problem is the back seems to be on in cardioid.

How do you come to this conclution? Did you try to disconnect the diaphragm on the back and compare?

In omni the pattern voltage drops from 48v to 30 volts but if I reverse the the front and back capsule wires I have the same problem but without the voltage drop.The relay checks out fine and all other voltages in the mic are are good.

You mean that the junction between the 14kOhm and 12kOhm resistor in the PSU have 48 Volt?
It should be normal that the voltage drop when you apply a load (relay)...
Not normal is that there's no drop when you rewire your capsule, probably miswiring, check with the step by step instructions.

 

[rrowley]

problem is the back seems to be on in cardioid.

How do you come to this conclution? Did you try to disconnect the diaphragm on the back and compare?

In omni the pattern voltage drops from 48v to 30 volts but if I reverse the the front and back capsule wires I have the same problem but without the voltage drop.The relay checks out fine and all other voltages in the mic are are good.

You mean that the junction between the 14kOhm and 12kOhm resistor in the PSU have 48 Volt?
It should be normal that the voltage drop when you apply a load (relay)...
Not normal is that there's no drop when you rewire your capsule, probably miswiring, check with the step by step instructions.

Success I must have had a bod solder joint as I resoldered some joints and all is now fine
Thanks to all
Rich

 

[JW]

Hey guys,
Is this sound indicative of bad tubes, or a dirty capsule/high impedance area or something else? http://www.supload.com/listen?s=pSLcIC

 

[living sounds]

Does anyone else have the problem with the SVT-700 and similar mic bodies that the capsule sits too high, just behind the metal ring surrounding the mic basket? This is already the case with the chinese capsule, and the Beez Neez one will be at the same position. There's no room to lower the base, so the only remedy I see is to saw away the ring...

 

[kante1603]

Does anyone else have the problem with the SVT-700 and similar mic bodies that the capsule sits too high, just behind the metal ring surrounding the mic basket? This is already the case with the chinese capsule, and the Beez Neez one will be at the same position. There's no room to lower the base, so the only remedy I see is to saw away the ring...

Hi,
not sure if you meant the SCT-700 (Thomann)?
If so I was able to lower it by using a different holder (used the Thiersch capsule) bringing it about 6mm down.It nearly touched the top of the basket.Not perfect but much better than with the normal holder.Will give it a listen when my psu is done.

Best,

Udo.

 

[The Frizzle]

Thanks 0dbfs, i won't risk it then, thanks for pointing that out..
I found an inside picture of another mxl mic:
http://recordinghacks.com/images/mic_extras/mxl/MXL2006-circuit.jpg
This is the MXL 2006, which has the minimum 50mm size.
But the PCB holder does not seem to be suitable whith that shape.
So maybe MXL is not the way to go..

 

[crackerzot]

Would someone be so kind as to help me figure out which pins on the Binder connector for my EQU47 mic shell connect to what on the MK47 board, specifically?

I've got 7 pins on the connector.  Which are unused on the Binder and where do the rest connect on the PCB?  I read an earlier post on the last page, but I'm still a little confused.  Please forgive my ignorance.  This is my first mic build project.

A friend is building the P/S for me according to the schematic on the first post.  I've got my Thiersch capsule.  All that's left for me to do is the connector wiring and install the capsule and the mic will be finished.  Many thanks in advance.

 

[living sounds]

Hi,
not sure if you meant the SCT-700 (Thomann)?
If so I was able to lower it by using a different holder (used the Thiersch capsule) bringing it about 6mm down.It nearly touched the top of the basket.Not perfect but much better than with the normal holder.Will give it a listen when my psu is done.

Best,

Udo.

Yes, I've got a similar mike (same factory and model, different brand). But then you get it closer to the metal at the bottom, which isn't ideal either....

 

[Sredna]

Hey guys, Is this sound indicative of bad tubes, or a dirty capsule/high impedance area or something else? http://www.supload.com/listen?s=pSLcIC

Strange sound, doesent sound like the bad tubes I had, maybe a bad connection?
A bad capsule could be noisy or give scratching sounds when breathed on, haven't heard
sound like this from a bad capsule.

Would someone be so kind as to help me figure out which pins on the Binder connector for my EQU47 mic shell connect to what on the MK47 board, specifically?

It doesent matter as long you keep record of your wiring. Ask your friend how he wired the connector on the PSU and do the soldering accordingly.

....problem with the SVT-700 and similar mic bodies that the capsule sits too high, just behind the metal ring surrounding the mic basket?

Dont forget that the U47 got the same (or similar) arrangement with the upper part of the capsule behind the ring. Maybe it's part of the sound! 

 

[kante1603]

Dont forget that the U47 got the same (or similar) arrangement with the upper part of the capsule behind the ring. Maybe it's part of the sound! 

@living sounds:
Yes-Sredna is right...here a link to pics of the original (scroll down to the 10th pic!):
http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Neumann-Mikro/U47/U47.htm
Therefore mine must be mounted nearly absolutely right-can´t wait to get this mike up and running!

Cheers,

Udo.