MK-U47 - build thread

[Category 5]

Well, I appreciate that...I've done research on it too; I guess I'm just wondering why Max in particular is suggesting the blue line.

Same reason they sell the blue line.  Historical accuracy and slight variation in tone.  Nobody ever said PVC will "degrade" over time.  Most people thought the older capsules sounded just fantastic so think of it like win that matures and improves with age rather than degradation.  The M7 was the original capsule and it was PVC.

I'm sure the red will be a fantastic option for folks that are worried about the change in sound, but keep in mind those can change too.  I am pretty sure the difference is that the PVC will tighten over time while the PET will loosen.  If you plan to use the mic in scenarios where very low end cent will be important than maybe the red is the way to go.

 

[rainton]

Well, I appreciate that...I've done research on it too; I guess I'm just wondering why Max in particular is suggesting the blue line.

Same reason they sell the blue line.  Historical accuracy and slight variation in tone.  Nobody ever said PVC will "degrade" over time.  Most people thought the older capsules sounded just fantastic so think of it like win that matures and improves with age rather than degradation.  The M7 was the original capsule and it was PVC.

I'm sure the red will be a fantastic option for folks that are worried about the change in sound, but keep in mind those can change too.  I am pretty sure the difference is that the PVC will tighten over time while the PET will loosen.  If you plan to use the mic in scenarios where very low end cent will be important than maybe the red is the way to go.

Well I also tried to find as much as possible on this topic and a lot of sources said PVC will "degrade" over time (i.e. K.Heyne, A. Grosser, etc.) :-\
And also explained how it happens and what it does to the sound (loss of low end; noise)

But I'm with the others that still couldn't make up their mind or get a clear picture of what to use.
And it's not true that all M7s were made of PVC, right - Neumann stopped using PVC in 1957 in favor for MCF (Macrofol) which is basically also PE like Mylar.
The only thing I know after reading all the articles is that it is clearly a matter of taste, too.
Anyway I guess the only way to find out for yourself is get both and hear them "side-by-side" under the same conditions - that's probably what I'll do  :

 

[electrisizer]

i read that blue line has bit smoother highs than red line - for a vocal mic i need smoothness. german singers tend to emphasize SSSSS and its difficult to remove after recording without sounding dull.
on the other hand its a pleasure to boost highs when they are smooth and open with a good EQ - thats the way i prefer. same thing for overheads... 

 

[Melodeath00]

FWIW, I have read Oliver say that only the blue line is "up to snuff," (my quotes, not his words) but that may have been an old comment, and I believe the red line/mylar may have gone through some different iterations/versions over time. Regardless, they use the blue line in the Lucas CS-4. If I were to replace the BeesNeez K7 in my mic, it would be with a blue line. In fact, I may do that anyway once I build a U47 FET.

EDIT: I found the post from Oliver I was thinking of, and indeed it was from 2008, and before he had even heard the PVC blue line. Regardless, he said the Thiersch mylar "did not cut it." Honestly, this may have even been before they were called blue and red. Regardless, I think the fact that they use the blue in the Lucas says something. I would go for PVC for authenticity, but that's me.

 

[chefducuisine]

Max,

no need to hurry - as we say: 'Gut Ding will weile haben...'
Thiersch states that the correct holder for an M7 is the STS 7a. Look at the third picture on Products/Holder STS 7, the last column mentions the microphone.

If you didn't have already - put me on the list for at least one.

Regards,

Christian

 

[Dr Gris]

I have an old M7 PVC (original, not a Thiersch Blue Line) and it has sure "degraded" over the
years, and is noisy. Thinking of having it reskinned with PVC again, but I'm not sure.
I have an original U47 with another original M7 (see reply #50 in this thread )
reskinned by Thiersch with Mylar, sounds darn good to me....

Best
//M

 

[Phrazemaster]

I have an old M7 PVC (original, not a Thiersch Blue Line) and it has sure "degraded" over the
years, and is noisy. Thinking of having it reskinned with PVC again, but I'm not sure.
I have an original U47 with another original M7 (see reply #50 in this thread )
reskinned by Thiersch with Mylar, sounds darn good to me....

Best
//M

Thanks for chiming in Dr Gris! Now I'm only completely confused.    lol seriously thx.

 

[ioaudio]

Re: Why i recommend the blue line:
In the past i remmended Thiersch's capsules with no preference, but i had three or more users changing to PVC after purchasing the PE red line capsule in the first place.
I'd say overall the feedback was better regarding the PVC capsule.

Re: Capsule holder:
The STS7 is available in three different heights 52, 55 and 58 mm - i was wondering which one most people here bought.

 

[Pip]

I hope this does not start a flood. But I bought a Blue Line only as a nod to antiquity and authenticity when it comes to originality. The Red line is just as good. If you read the info on the Thiersch site it is stated that sonically they can detect no difference (with the equipment they own) they only started making the PVC membrane capsule because of customer demand due to a move towards original authenticity not sonic variance. I will also be buying a red line for other mic projects. I actually go with Mr. Grosser on this even though I decided differently. If you want a mic that will stay healthier longer, buy the Red Line.


http://www.thiersch-mic.de/en/estm_ablauf.html

 

[Phrazemaster]

Thanks Max and Pip for adding to this. I didn't mean to hijack the thread getting on about this, but since it was brought up I thought to ask for clarification.

Thanks much,

Mike

 

[ciscan.81]

Thanks everyone for the red/blue info...it all helps when trying to chose 'sound un-heard'...

On another topic...

Max (or anyone else thar knows) what tubes are you recommending for this project? 6028/408a as per the MK47?

I know this was touched on earlier in the thread, but I'm still not clear.

I'm in the process of ordering some tubes for a couple of other projects and would like to order them all at once if I can.

Thanks

 

[Nele]

Re: Capsule holder:
The STS7 is available in three different heights 52, 55 and 58 mm - i was wondering which one most people here bought.

For my Skylar-body rendition of your mk7 I used the 58mm version. This places the capsule above the center of the headbasket, as was originally the case. You could always choose a version and use acrylic spaceplates to raise or lower the capsule.

 

[Le Roux]

STW 7.1 - Blue & STS 7.1b 52 mm and the D7.1

"We have only STS 7.1b in stock. The mount is with transducer and head/roof 52mm high."

 

[sr1200]

I was about to start my own u47 project using the nuvistor circuit.  This looks like its gonna beat the snot out of what i was planning.  Is there a list i can get on?

 

[ciscan.81]

...For anyone else who needs something to help tip their scales regarding the capsule choices...

I sent a PM to a GDIY member who built 3 MK47's (in a couple of different bodies). He used 3 different capsules: a Theirsch Blue line, Theirsch Red Line and BeezKneez M7.

I asked if after 6 months with the three mics he had a preference, his response:

If i had to buy another capsule now I would still get the Blue line.  It just has a sound I prefer overall.  It is subtle but I do prefer it.

Obviously there are other variables (eg. BeezKneez was in different body to the 2 Theirschs) and it is just one guys opinion/taste...BUT with all my other research, it was just enough to help me settle on a choice...FINALLY!  ;D

 

[Phrazemaster]

...For anyone else who needs something to help tip their scales regarding the capsule choices...

I sent a PM to a GDIY member who built 3 MK47's (in a couple of different bodies). He used 3 different capsules: a Theirsch Blue line, Theirsch Red Line and BeezKneez M7.

I asked if after 6 months with the three mics he had a preference, his response:

If i had to buy another capsule now I would still get the Blue line.  It just has a sound I prefer overall.  It is subtle but I do prefer it.

Obviously there are other variables (eg. BeezKneez was in different body to the 2 Theirschs) and it is just one guys opinion/taste...BUT with all my other research, it was just enough to help me settle on a choice...FINALLY!  ;D

I already have a U47 clone in the making and I have a red line. For me it makes sense to venture into blue territory lol...although I'm a little disappointed we never really heard of the fruits of Klaus' collaboration with Thiersch or if they ever really bore fruit...I'm game to try blue this time.

Thanks for the sharing ciscan

Mike

 

[benqbasic]

Everything wired but the capsule and connector:



img]http://www.twin-x.com/groupdiy/albums/userpics/wired2.jpg[/img]

Hey Max,
I've just noticed your using what looks like K42Y capacitors. I haven't seen them come up in discussion about the U47 although i have used them in non-mic circuits. Did you select these capacitors for sonics?

Cheers

 

[ioaudio]

Re: tubes for in the MK-U47

I still like the simplicity of the one-supply solution with two 6028 tubes.
Plug and Play compatibility with VF14 tubes makes this solution attractive to those lucky enough to own one.

Additionally i decided to open the system to work with other tubes by optionally adding a seperate heater supply.
The MK-U47 can be used with various tubes - steel types (eg. EF12, EF12k, EF14) or one of the wide variety of glass tubes - in many configurations (self biased, forced bias or fixed bias)

Re: height of the capsule holder
Thanks for the stock update, seems i will have to include acryl spacers for different holder types/heights.

Re: capacitors

Yes, I'll include K42Y caps as filter and output capacitor - i like them and i saw them in various high-end U47 clones.

-max

 

[Phrazemaster]

This is getting exciting Max! Can't wait!

 

[Woot]

This is getting exciting Max! Can't wait!

Absolutely! Can't wait. I'm in for 1.

8)

Thanks Max