MK-U47 - build thread

[Baltazar]

My first one is finished , this was a LONG wait for the M7 !

I'm not sure about the wires of my Thiersch M7 Blueline,  is this correct ?
The omni switch doesn't work, mic stays in cardioid,
and when I touch the body, I get very loud noise.
Any tips ?

the mic itself works perfect and is very quiet ! I use RCA408.

Looks very nice!!
What height did you use for the capsule holder, cause that is thiersch capsule holder?
Do you have a picture of your PSU? Need inspiration  :

 

[kosi]

Yes, this is the Thiersch capsule holder.
I didn't use any of the distance pieces, the normal height looked good to me, so I just kept it like that.

I use for my PSU an old Gefell N61 housing, which was not such a good idea. It has many holes in the wrong places.
Then I also made some logistic faults, so I ended up with a very DIY looking PSU...
Will post a pic, when I'm in the studio.

After my first test in the studio, I am very satisfied with the touch sensitivity of the body, my original U67 has the same level.
I guess I never noticed before, cause I never held the U67 in my hand...
I use the big Rycote mount and in this one, the 47 is VERY unsensitive to touching, so pleasant surprise.

Unfortunately, the noise level is pretty much higher than my U67, so I have to look around for new tubes. Difficult job.
But nevertheless, the sound is superb and I won't hesitate to use it in productions from now on.

When I have time, I will fetch a few U47s from friends (actually I know 5 U47 users) and compare them.
I already did some comparisons with my U67 and it left me all smiling

 

[kosi]

Here my rough PSU

 

[kosi]

back (or front)

 

[chefducuisine]

kosi,

you can hear mine here (together with two DIY U87 as room mics).
I ended up with using WE tubes...
http://groupdiy.com/index.php?topic=59704.0

 

[marcelkroese]

Burn Baby Burn

 

[Pip]

Burn Baby Burn

How hot is the area where the drop-down resistor is attached to the base getting?

 

[kosi]

HOT !
But I can touch it

recording as we speak, btw

 

[marcelkroese]

Very hot! Can just bear it.

 

[Pip]

HOT !
But I can touch it

recording as we speak, btw

Glad to hear it! I have had this in use for awhile and was just not sure it was supposed to get as warm as it does. I noticed Max went with a 10Watt 1.5K resistor this time.

I am in the process of burning in some new tubes. Just because there is a difference in sonics and gain between the Phillips/JAN and the WE. I just cant make up my mind. Both have there merits and drawbacks.

 

[Baltazar]

Finished, mine a couple of days ago, redline capsule, philips tubes and a thick film resistor for the negative biasing resistor.

Did a really quick comparing against our UM57, i know it's not the same mic at all but it has a nice character and works really good. Some quick thoughts:
The UM57 has smoother top, bottom is pretty similar, even though the mk-u47 goes a little deeper, mid not as present or nice as the mk-u47.

What i'm going to do is try some other tube brands and different neg biasing resistors. I also got an old Bosch I really wanted to use for coupling cap, but it was too big to fit . Going to try to modify the inside of the mic to make it fit...

I would want to smooth the high out a bit, some letters really slams through a bit too much now in my opinion.


Anyway, thank you Max for an fantastic design, kit and quick shipping!!

 

[ioaudio]

Thanks Baltazar!

before you start drilling holes I'd recommend giving the blue (PVC) line a chance.
I'm pretty sure the bosh cap wont change the timbre enough, based on how you describe the sound.
If you decide to go for it, Thiersch's capsules hold their value well and some even prefer the more modern sounding red line.

-Max

 

[Baltazar]

Thanks Baltazar!

before you start drilling holes I'd recommend giving the blue (PVC) line a chance.
I'm pretty sure the bosh cap wont change the timbre enough, based on how you describe the sound.
If you decide to go for it, Thiersch's capsules hold their value well and some even prefer the more modern sounding red line.

-Max

Wow, that reply was even quicker than you ship!

Then i might just place an order for a blue line... Or maybe build another one...

But that bosch cap looks so good....

Also want to add i had no problem with unreliability on the philips tubes, the noise floor is very low.

Edit: Added a picture of my psu..

 

[Pip]

So in the interest of not taking up more space then necessary I have come to, at least for now, some tube conclusions:

http://groupdiy.com/index.php?topic=47112.msg764053#msg764053

http://groupdiy.com/index.php?topic=47112.msg764111#msg764111

 

[Baltazar]

Ok, couldn't resist to place and order for a Blue line, so i did...

Difference is quiet big, s:es and k:s are softer and over all a lot less sibilant.

The blue line is definitely the capsule to go for in this build if you primary plan to use it for vocals.


I have to say I'm not a huge fan of the magnet solution to change the characteristic of the mic, worked perfect before. But cant get it to work perfect again.. its VERY sensitive and precise and the feeling of the "switch" is not very smooth. But thats my only concern around this build! 

 

[stelin]

I have delivered two MK-U47s to Pama Studio 3 in Sweden today.
We spent the afternoon comparing the two MK-U47s to Pamas original U-47.
The general conclusion was that it was very hard to distinguish the original U-47 from the two MK-U47s. There where small differences, but no more than you would expect from different copies of "the real thing".

 

[ioaudio]

Nice! Do you happen to know which capsule sits in the original U47?

-Max

 

[Phrazemaster]

Max, at one point you mentioned you were working on an M7 of your own, as well as a PSU for this kit.

Are those still in the offing?

By the way, I'm sure you have spent some time in Klaus' forum for microphones. He says no one has nailed a real M7 in years. He thinks it's because the PVC material has changed. Just wondering if you were going to continue this research, and also suggest you contact him as he might be willing to offer suggestions/guidance if you wanted it.

Hope this isn't too far OT; just wanting to make the best MK-U47 possible (hint, hint!)



Mike

 

[Phrazemaster]

A quick question regarding the PSU - Max do you have a schematic for it specifically, or you are recommending the Zayance or a real Neumann PSU?

I'm tempted to go PTP on this one, as I want to mount the resistors off-board anyway; I'm not certain what value the Zayance PCB will provide with more than half the components not even mounted.

I do have a question regarding the LED that is on the Zayance PCB - how does this not get fried? I thought LED's were around 5V or such; I can't see how the voltage gets dropped to support it...or are there some high-power LEDs out there of 105V? I tried doing the math on it and can't figure this...any thoughts, anyone?

Thanks

Mike

 

[stelin]

Max, the original U47 has a K47 capsule. The two MK-U47s have Thiersch Red Line capsules.