Some questions related to mic builds

Hi!

I'd like to ask few questions that I still didn't found answers for.
It is hard to grasp everything so maybe I've missed some answers in build threads, but I did try to search before asking here.
I don't want to clutter the forum with many separate threads so I'll throw all into this one and hopefully some will be answered


1. Why are keystone turrets important? How do they differ from regular pads on pcb? I know they are here to isolate Hi-Z components, but is it so crucial to have absolutely no contact with pcb on those spots? Why can't there be just unconnected solder pad and we would then solder regular pin to that?

2. I see a lot of hype on M49 that is making me reconsider my long waiting U47 (D-47 or D-EF47) build. I've never heard M49, but from what I assume they are in the similar lane. Is it worth to jump over U47 and go straight to M49? I must say that I've recorded on original U47 and tried one clone of it and I'm absolutely in love with it's character. Is M49 even better?

3. Some mics have single and some have dual layer mesh on the head grille. Is my assumption correct that single layer mesh will let in more high frequencies from the source so it is supposedly more natural in capturing sound to the capsule? Or there is some other trick?

4. Some builders use teflon wires for internal wiring. Is it an obvious difference from regular wire, considering those are really short wires and they are not exposed much to RF/EMI/junk inside metal body of the mic? Or is it related to capacitance of the wire, even for such short runs?

Maybe I'll ask few more questions if I don't find answers in other threads.
Others may feel free to ask their own.


Luka

1.  You are dealing with super high impedance .  Board leakage too high.
2.  I love my M49s.  M47s too.  YMMV
3.  resonance.
4.  No teflon for me.......maybe some insulation?
Best,
Bruno2000

I don't know about a few of your questions, but I did talk to the makers of the Vanguard V13, which has a single layer open head basket like an AKG C12. I had asked if they had sort of cloned the Manely Ref Cardioid and this is what he said:

"No, there's not really inspiration from the Manley Ref Card, although they did take the mic hot-rodders approach to the open headbasket (helps reduce internal reflections/nodes - George Neumann always said the best mic headbasket is no headbasket at all!). I believe this was first popularized by Mike Joly on Gearslutz a while back, but it's really simple - if you have several layers of mesh, you create a closed cylinder and a serious problem with resonant frequencies. It's a big part of why poorly-designed cheap mics have that "eshy" bright sound - it's not only a property of a bright K67-style capsule paired with a bright circuit, but also a significant buildup in the headgrill between 3-6k (depending on the diameter of the interior). The headbaskets by Neumann are steepled to avoid this buildup (non-parallel surfaces near the capsule), but an open headbasket provides a very natural sound while still protecting the capsule from physical damage."

I thought that was a cool answer so I wanted to share at least that.  Going back to the "M49" I have also heard that is a really awesome mic and I've also heard that the U47 is the one for male vocals. I personally decided to build the D-47, but I can say, as a beginner to mic building, there's more to it than I thought. I thought the kit was designed like a sort of "paint by numbers" type thing and its isn't. I'm feeling pretty good about it, but I have for sure had to ask some beginner questions and have read for a couple days on just the power supply because the voltage is so high I don't wanna hurt myself or burn down my house. Still, I'm pretty pumped about it and totally looking forward to using it when its all said and done, but I am taking my time with it. 

Why does u87 have a triple mesh then?

I'm afraid it's more complicated than this, but I don't think mic designers say i'll use this or that 'couse it sounds this or that way. You simply have to test it. Same for m47/m49. Taylor Swift's producer thinks Avantone CV12 is ''better'' than both of these, in the genre, her voice , and I am sure it is ''better''.

This might sound funny, but for years I've been avoiding Behringer B-1/B-2 because of bashing from all the ''experts'' regarding it ultimate Chinese crap mic.  Until I tried it being aware of absence of HF rolloff! Since then I use 10 of these, with various mods, or none, but with  EQ on a pre or post, painted in various ways (for those who look but not listen), with single and double grille depending on application. They are on every session along u87s, KSMs, ATs, diverse rental mics.... Tracks are being sent to various engineers for mixing, and no one ever asked what crap were using on this or that. But I can tell you I have heard, wow man, what is that mic on that source, sounds great. ....blah just a custom thing built buy a guru...

Last mod I did on my b2s is one suggested by Ruud on this forum, but then in7d told it is not a good idea, then Ruud said the other part of the mod  in7d suggested was a bad idea. And I ended up doing both on two different mics. guess what? I kept both mods! Sounded great, and different. Same happened with my Groove Tubes mic.

I know it's a crappy answer, but until you build both you will never know. I bet you will come to the same conclusion everyone hates. ''It depends on the source''.

And yes, when I shootout mics on what ever source, no matter if it's mine or rental, I don't know which is which. It has to be blind. I hate when I spend tons of hours on something and it gets beaten by a cheap thing lying in my drawer, but it happens. All the time.

kingkorg: I know what you mean...obviously this answer was one particular mic builders answer, but I can say this...that particular mic, from what I've heard ( I bought it btw) is pretty nice and a lot of people like it. I watched one studio guy talk about how he put that V13 up with his U47/269 and the singers chose it and a couple actually went and bought one right away. Anyway, I have a $150 mic  I really like and NO ONE says "man, that sounds like a cheap mic"

as far as the 87, I was told/read somewhere that it specifically has the grill in the shape its in for resonant frequencies and I can't remember who, but one company was actually made to stop using that grill because Neumann had a patent on it. I don't know...I am one of those people that can use just about any mic, but not everyone is like that and there are absolutely differences between really nice, well built mics and not so nice...and I don't mean price exactly because I've heard some mods that sounded really nice, but they were given some TLC and put together well. How many times have we heard people preferring the sm7 over a U87...all about context and voice type as cliché as it is, it seems to be true

bruno2000 said:

1.  You are dealing with super high impedance .  Board leakage too high.

4.  No teflon for me.......maybe some insulation?

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I would think these two are related, specifically with any wiring connecting the capsule (read that again, super high impedance). Teflon has higher resistance and lower leakage (I think by many orders of magnitude) than does the common plastic insulation used on hookup wire, and you would want to use it to connect the capsule for the same reason you use turrets for connections.

Keystone turrets with teflon insulators for the very high impedance connections are a good precaution. I haven't built a mic without them.

I like silver coated Teflon wire because it doesn't melt back when soldering. As mentioned by benb, Teflon is also the best dielectric. However, it is a bit of a pain in the ass to strip compared to PVC. I also use silver solder with silver coated wire, seems to flow and adhere better. YMMV.

The headbaskets do affect the sound, but not nearly as much as the capsule, transformer and tube. The U47 basket is a part of the sound for sure. The angling of the M49 headbasket was to address that "flaw". The patent for the M49 headbasket has long expired, so anyone can use it now.

M49 sounds different than U47 due to different transformer, tube, headbasket, and circuit. It's a sum of the parts. I would say the M49 is more flexible and less colored than U47. As someone said, U47's midrange "thing" can really be magic on male vocals. I understand Norah Jones bought a M49 that she particularly liked. But I've used U47's on female singers with spectacular results. You just gotta have them all!

George Neumann always said the best mic headbasket is no headbasket at all!

Click to expand...

Does make you wonder why Neumannn headbaskets have no less than three mesh layers.



AusTex64 wrote:

I would say the M49 is more flexible and less colored than U47. As someone said, U47's midrange "thing" can really be magic on male vocals.

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Yeah, the U47 basically has the same capsule, but it does have this added edge that to my ears is somewhat metallic. This works great on some male vocals and not so great on others.

-teflon pins are ok when a pcb is used but point to point is more long term reliable for me in the hi-z section (like in the u87,u67,u47,c12,elam...)
i've just serviced two c414eb and i've cleaned the pcbs during two hours !!!Recent pcb materials seem to be more reliable, but for me the best option is to encapsulate the hiz section (u87,u67,m49...) for lesser long term moisture contamination and
better resonance immunity.

-M49 is a must have in a high end recording studio, different animal than the u47 but same family, more flat , very nice highs

-headbasket (meshes and shape) acts definitely on microphone response : internal resonances , immunity to plosives, directivity ,sibilants, etc...
that part is a major element of the mic sound

-teflon wires is needed for insulation in highz section

regards

micaddict said:

Does make you wonder why Neumannn headbaskets have no less than three mesh layers.

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It's German-built, like a tank. In case the microphone stops functioning it can also be used as a hammer, air filter, or door stop. If the valve is still operational, it's a space heater.