MK-U47 - build thread

[Pip]

Thanks Stefan,
I´m using the 200mA fuse now and no blown fuses so far.
I know that the fuse is not impacting the current draw, only limiting it and I also figured that the initial impulse when powering on is probably blowing the 125mA fuse. I was only concerned that the 200mA fuse is would limit the current past the power rating of the transformer (could reach 44VA with this fuse) but it is not likeley that a permanent 200mA current draw should occur.

The mic is working fine in cardio btw, but no omni, but I already know the reason and will fix this shortly.
Using Philips Miniwatt tubes and burn in is still ongoing. Have some Tungsols, they are next. Trying to get some WE´s.

Are your Philips Miniwatts microphonic? When you tap the mic body do they make a ping sound?

After much research my suggestion is you want to look for made in USA WE tubes with the large font. I believe these are older than the others available and there is no doubt in my mind anymore that they are the lowest noise of the WE's. If you can find some Ericsson 408a's they are the best noise to microphonic in my experience and sound great. The Philips TS62 Miniwatts sound the best out of all I have tested but they are the most microphonic.

Yes, quite microphonic. They are cooking for some 10 hours so I´m still burning them in and hope this will improve. I´m very happy with the sound (classical guitar sounds magic, voice very natural and warm), but didn´t compare them yet to other tubes.
Found some 50ies WE 408A in nostubestore.com (got the miniwatts there as well, gold pins O-getter), the guy has just 4 left don´t know if they are paired still waiting for a reply.

Yeah sadly I had no luck with the microphonics getting better after 3 days of burn in. That said, I think they are the best sounding of all the 408a's I have tested so I suggest recording for a bit and see if they have any noticeable problems. If you only hear problems when you touch the mic I ask myself is this a problem.

 

[Bowie]

Yeah sadly I had no luck with the microphonics getting better after 3 days of burn in. That said, I think they are the best sounding of all the 408a's I have tested so I suggest recording for a bit and see if they have any noticeable problems. If you only hear problems when you touch the mic I ask myself is this a problem.

  Microphonics generally don't improve.  If they start out bad, chances are that they'll get worse from heating and cooling cycles (warpage).  The problem you might end up having with your tubes is that a vocal/instrument can vibrate a mic more than you might think, leaving a trace of microphonic reverb in your tracks. 

 

[Category 5]

The polystyrene capacitor can also be responsible for microphonics.  Make sure the leads are short and tight. 

 

[Pip]

The polystyrene capacitor can also be responsible for microphonics.  Make sure the leads are short and tight.

Very true indeed. But this is not that, every Philips Miniwatt TS62 408a (at least a dozen pairs)  I have tested was quiet electrically, no hissing or popping,  but microphonic. They sound damn good though until you tap the body and then it is a high pitched ring. Yes I am worried that if the mic body is concussed hard enough by a sound wave it might get into the recording but so far I have not noticed anything. But have as of yet not used this configuration for room mic on drums or in front of a guitar cabinet.

 

[gbruler]

Hello everyone,

Can someone please explain to me how to connect the microphone to the pattern switch? I can't figure this out.

Thanks

 

[djn111]

Hi,

What do you mean,  the place of the reed switch ? Be aware the magnetic field of the magnet makes circles, so the middle is not the strongest field. I will post some pictures tommorow how I solved it.

Djn

 

[gbruler]

Hi,

What do you mean,  the place of the reed switch ? Be aware the magnetic field of the magnet makes circles, so the middle is not the strongest field. I will post some pictures tommorow how I solved it.

Djn

That will be great, I am really not sure how to work with this thing..

Thanks!

 

[djn111]

The promised foto's and explanation:

First of all, the magnet and the reed switch should not be in the middle, the magnetic field is the strongest about the edge of the magnet.

How to test if you did it right or not.

I, first put in the mounting plate of the capsule, low Z board, and lined it up in the headbasket, now you can mark out with a marker, where the magnet is in the cardiod and round position.

After that I mounted the reed switch with two little M2 bolds, and al the rest normal. now you can check with a multy meter if it works. But to be shure, I put the whole thing together, and checked again.

Because I used the two little bolds, I can measure the working of the switch with the head basket mounted, hope this helps.

And when you are shure everything is working properly, switch the bolds one by one for the original ones, and mount the rest of the parts.

Djn

 

[gbruler]

The promised foto's and explanation:


First of all, the magnet and the reed switch should not be in the middle, the magnetic field is the strongest about the edge of the magnet.

How to test if you did it right or not.

I, first put in the mounting plate of the capsule, low Z board, and lined it up in the headbasket, now you can mark out with a marker, where the magnet is in the cardiod and round position.

After that I mounted the reed switch with two little M2 bolds, and al the rest normal. now you can check with a multy meter if it works. But to be shure, I put the whole thing together, and checked again.

Because I used the two little bolds, I can measure the working of the switch with the head basket mounted, hope this helps.

And when you are shure everything is working properly, switch the bolds one by one for the original ones, and mount the rest of the parts.

Djn

Hey Thank you very much for that, I finally had time to check this out, and apparently I broke it, and I guess that is why it didn't work, so I'll get some new ones and try to fix it.

Thanks again!

 

[Energizer]

Hi, I hope everyone is enjoying this year's end celebrations 

A couple months ago I built a pair of MK-U47 (Thiersch Red Line capsules and Zayance's PSUs).
The first mic works flawlessly but I noticed the noise floor was significantly higher on the second one.
Then the situation got worse as I get loud scratching noises and all kinds of clicks and pops that seem to come back each 5 minutes or so. The sound seems to be OK but these noises make the mic unusable...

Here are some audio samples :
https://www.dropbox.com/s/opvij2ztgbmzxos/mk-u47%20noise%201.wav?dl=0
https://www.dropbox.com/s/hcwea75kdn1gigl/mk-u47%20noise%202.wav?dl=0

So I was wondering if someone had experienced similar issues ?
Could it be a faulty tube, or maybe a problem with the reed switch ?

Thank you all very much for your help 

Brice

 

[djn111]

Hello,

I would start, with swaping both tubes. Between mic's if the problem swaps with it, you can suspect the tubes.

Djn

 

[Sredna]

Yes, probably the tubes.
I bought 10 pcs and had to try a good while to find a working combination.  8)

 

[Energizer]

Thank you for your replies, I'll try to swap the tubes and I'll keep you posted.
Happy New Year's Eve
Brice

 

[gbruler]

Hey everyone! 
A couple of days ago we have rented a real vintage U47 from a local studio, so we've done some tests. We had an important recording, and I've put both the vintage U47 and our MK-U48 in front of the singer.
Now I'm not really sure what's the condition of the Vintage U47, It looked and sounded really good, but it's the first time I use a real one. I'll leave the clips in here so you can judge for yourselves, but it seems like our MKU48 is really dark. We have nice Westren electric tubes from Christian Whitemore, and a beezneez capsule (I suspect that could be the issue). It seems like if you put a high cut on the Vintage U47, or a high shelf on the MKu48 it seems to be pretty close (didn't have time to really dig into it).
Here are the files (recorded through Sound skulptor's MP73 at exactly the same settings):
U47 - https://drive.google.com/open?id=0ByyLGJW4qi4eY2VQQXM1eU5ZVjA
MKU48 - https://drive.google.com/open?id=0ByyLGJW4qi4eS2VkSmdndW0wMjQ

So what do you guys think it is? is it the capsule or maybe something else is wrong?
I just want to add up that I have asked Ben from Beezneez about it, and he was willing to hear some clips, I sent him some clips almost 4 months ago and he didn't answer.

Thank you all for your help

Edit: Sorry if the links didn't work, they should work now!

 

[o3misha]

For less low end and more bright sound you should use 60M grid resistor instead of 100M and 0.5 uF output coupling capacitor instead of 1uF. Also, you may try K67 style capsule.

 

[stelin]

I don't think changing the grid resistor will help if you have a Beezneez capsule.
I have two Beesneez CK12 capsules and they both sound "dark" (or "warm", if you like the sound) on voices, since they have a rather big dip around 5-6 kHz (in the "ess" area).  The dips in my CK12s are about 10dB deep, and you can't fix that with a grid resistor change.
You can find clips on YouTube with Beesneez microphones. They all sound a bit dark (or warm). That's how Ben like to tune his capsules, I suppose.
I have Thiersch Red line capsules in my MK-U47s, and I have compared them to an original U-47 with a K49 capsule. You have to listen very hard with very good monitors to tell them apart.
If you are trying to contact Beesneez, send an email to Veronica instead: [email protected]

- Stefan

 

[Delta Sigma]

...and a beezneez capsule (I suspect that could be the issue)...
I just want to add up that I have asked Ben from Beezneez about it, and he was willing to hear some clips, I sent him some clips almost 4 months ago and he didn't answer....

Which capsule? The K7 or M7? The K7 is supposedly an M7/K7 hybrid. Possibly a little darker than an actual K47. Their M7 I expect would definitely be darker. I'll also add to contact Veronica. I think they're a little busy right now though. I too have sent a message and not heard back.

...I have two Beesneez CK12 capsules and they both sound "dark" (or "warm", if you like the sound) on voices, since they have a rather big dip around 5-6 kHz (in the "ess" area).  The dips in my CK12s are about 10dB deep, and you can't fix that with a grid resistor change...

I have a Beesneez Arabella with a K7 capsule and a DIY U67 with a K6 and I don't find either to be darker than I expect. That being said, I don't have much to compare to. If there is a darkness or a dip in the high end, apparently I like it. I quite like both mics.

 

[gbruler]

I guess I forgot to mention it's a K7 capsule.
Did you guys hear the clips? It's very noticable difference. It's not just a little darker. But again, when I raised the high end it sounded really close to the original U47, so yeah, it might be just how the capsule is tuned.
I will try Veronica's mail, see if it helps.
Anyway, if you do think it's the capsule, would you live with it and just use eq to raise the top end, or would investigate in maybe replacing the capsule?

Thanks again for your help

 

[stelin]

I have heard the clips. The difference in sound between your clips is the same, relatively speaking, as it is in my MataChunger C12 when I compare the Beesneez CK12 to the Tim Campbell CT12. 
If you like the "Beesneeze sound" you could call it warm, smooth and rounded. If you don't like it you might say that it sounds like there is a blanket over the mic.
My humble opinion is that if you want your MK-U47 to sound more like the original U47, you should try a different capsule.

 

[Delta Sigma]

@gbruler

I finally listened to those clips on my monitors. Your K7 shouldn't sound like that. My Arabella (K7 through an EF12 circuit) has no trouble with high end.  Check out Chunger's recording's of an MK47 with a Beesneez M7, which I would expect to be slightly darker than the K7:
https://app.box.com/s/dwdl8htubzwbp3wos0ym
https://app.box.com/s/50cp8xnfa601ih141xmj

Here's the whole shootout:
http://studio939.blogspot.ca/2014/11/vocal-microphone-and-capsule-testing.html

I'm planning on building an M7 and was trying to decide between the Thiersch Blue Line and a Beesneez M7 and decided on the Blue Line for a slightly warmer or darker sound than my current all Beesneez selection.

Even in deciding this, I have to remember that no shootout is perfect especially when comparing capsules in DIY mics where so much can be different beyond the capsules.

It's a lot cheaper to troubleshoot caps, wiring, etc than capsules. I think you should start there. You could also identify your location and see if there is anyone nearby who would allow you to try a capsule swap.

Did you follow proper Hi Z installation practices? Esp gloves and cleanliness when installing the capsule.
http://groupdiy.com/index.php?topic=58771.0

@stelin

I don't have much to compare to, but I wouldn't call the muffled sound in the above clip the "Beesneez sound".