DiY U47fet Ideas?

[Deadly Mix]

I want to build a mic, but a DIY or knockoff mic would never get chosen for vocals over some of the great mics we have and I don't see the point in working on a mic that won't get used. So, I was thinking, "Why not build a mic for sources that we're not naturally built to scrutinize so thoroughly?"

The mic that comes to mind when I think "great mic, not for vocals, and we don't currently have one" is the Neumann U47fet. I'd love to have one for bass cab and kick, but I'm in no hurry to spend $5k on a kick drum mic when I already get good bass and kick without it. So, that seems like a prime candidate for a build.

I've been over some old posts seeing a bunch of BM800 conversions, but I'm not entirely sold on the kick drum samples I've heard nor the look.

Any alternative idea?
I'm not looking for the absolute cheapest way to go. I'm looking to build the best U47fet knockoff possible, even if it costs more than a typical build. Just not so expensive that I might as well continue to wait until I'm ready to justify buying a real one lol, which is a fairly high spending cap for a diy build.

So, if there's a better capsule than the RK47 or any other part, even a better headbasket/body, I'm interested. I know there are some members here who know about building the way I know mixing, so I'm sure there are some great ideas to be heard.

 

[mrgrooves666]

Milan from VAMI sound has 47 pcb kit for through hole components (https://vamisound.com/kits/v47f/). You can now get the good body replica @ ali express. Traffo from Moby (https://www.mobytransformers.com/), or UTM/Igor. Capsule, Ari should come soon with her authentic K47. That ought to make a good mic.

 

[EarthTone]

I used Dany’s PCB’s, his D7 capsule, and Cinemag’s remake Trafo and could not be happier. On the next one I have a Moby trafo and will see what the difference is, but it’s probably my favorite DIY mic I’ve made so far, and one of my best mics overall.

Don’t use that china 47 capsule from mic parts! It sounds like crap.

Ari at Arienne Audio will soon release her k47 standard capsule. I am sure it will be very solid. Her stuff is great, for DIY.

 

[Khron]

Or if you're not in a humongous hurry (and are not expecting the sound of a possibly overdriven mic circuit), i've got some things in the pipeline. Including things to make stuff like the Chinese K47's sound less obnoxious

https://groupdiy.com/threads/feeler...-upgrade-boards-opamp-jfet-u87a-fet847.87606/

 

[Deadly Mix]

I've obviously never built a capsule, so I'm not sure why it seems to make such a big difference (or at least be so common among mics that I love) and I was actually wondering why having one seems to make mics so much more expensive. So, anyone able to fill me in on what it is about brass ring capsules?
Are they that much more to make? Why?
Is the brass a significant factor or is it just part of a technique/design that was more common in a time when people invested in the labor required to make a glorious capsule??

AKG comes to mind when I think of a mic that had a brass capsule, switched to a mylar capsule, and the sound quality plummeted. I can hear the difference, but I don't understand what the connection is.

Is this something I should consider when looking for a capsule in the pursuit of a mic worth choosing in a locker with top tier mics?
They taught us quite a bit in college and we even made these shitty little ribbon mics to understand the concept more than anything, but my training revolves around using the tools and I've been wondering about this.

Feels like something that would help me mic choices when shopping for capsules

 

[Khron]

I've obviously never built a capsule, so I'm not sure why it seems to make such a big difference (or at least be so common among mics that I love) and I was actually wondering why having one seems to make mics so much more expensive. So, anyone able to fill me in on what it is about brass ring capsules?
Are they that much more to make? Why?
Is the brass a significant factor or is it just part of a technique/design that was more common in a time when people invested in the labor required to make a glorious capsule??

AKG comes to mind when I think of a mic that had a brass capsule, switched to a mylar capsule, and the sound quality plummeted. I can hear the difference, but I don't understand what the connection is.

Is this something I should consider when looking for a capsule in the pursuit of a mic worth choosing in a locker with top tier mics?
They taught us quite a bit in college and we even made these shitty little ribbon mics to understand the concept more than anything, but my training revolves around using the tools and I've been wondering about this.

Feels like something that would help me mic choices when shopping for capsules

http://www.saturn-sound.com/Curio's/akg's ck12 capsule.htm

That should contain hopefully at least SOME answers to those questions, although you maybe possibly might not be asking the right ones, as it were But the "brass vs. Teflon" (not Mylar; virtually all "pedestrian" condenser diaphragms are gold-coated Mylar of one description or another ) is an AKG-only thing / debate. No such issues with other large-diaphragm condenser capsules.

 

[TLRT]

First I would start with a premium quality capsule,I built many 47fets with M7,although Neumann never did that,it works very well both for vocals and instruments too. Other option is K47 original, that ain't cheap, but works very well.

 

[Deadly Mix]

First I would start with a premium quality capsule,I built many 47fets with M7,although Neumann never did that,it works very well both for vocals and instruments too. Other option is K47 original, that ain't cheap, but works very well.

So you're thinking like a Thiersch? Klaude Heynes recommended having Thiersch take care of maintenance on a vintage U87 I'd picked up from another studio awhile back and I have nothing bad to say. In my most anal "everything has to be top because that's what people are paying us for" mentality, I have nothing but praise to give. I'm not even entirely sure what was involved, but the mic came back better.
That was a Neumann U87 though. You really think its a good choice to build a U47fet? I'm not doubting you. I'm just curious.

I suppose it makes sense. U67 owes its lineage to the U47, the U87 was to be the fet U67, U47fet is the fet U47 (obviously lol), so it kind of makes sense.

 

[Deadly Mix]

http://www.saturn-sound.com/Curio's/akg's ck12 capsule.htm

That should contain hopefully at least SOME answers to those questions, although you maybe possibly might not be asking the right ones, as it were But the "brass vs. Teflon" (not Mylar; virtually all "pedestrian" condenser diaphragms are gold-coated Mylar of one description or another ) is an AKG-only thing / debate. No such issues with other large-diaphragm condenser capsules.

Wow. Thank you. That's not gonna make me by any means an expert capsule builder lol, but I finally understand why, other than Bock, nobody's "clone" mics ever come anywhere near the real top tier mics (U47, C12, 251, C800-G). It appears the answer is that, even if you have instruction in front of you, top tier capsules are just REALLY hard to make. Materials cost a bit more but you're paying for an extremely skilled master of their craft to build each one over the course of a significantly longer amount of time than a Chinese or even more common decent capsule. Correct? I also understand now why, when I attempted to buy a brass CK12, they wanted so much money that I could've bought a Telefunken remake of the whole mic for very little more lol.

So, did Bock have a guy we could be buying capsules from, or did he make them himself?

 

[Khron]

That's not gonna make me by any means an expert capsule builder

Who says it was supposed to? And i slightly misspoke earlier - "even" the CK12 is included among the "pedestrian" capsules that are based on gold-sputtered Mylar diaphragms.

top tier capsules are just REALLY hard to make

Thaaaaaaat's... kinda-sorta relative(?) - case in point: https://groupdiy.com/threads/soliloqueens-k87-k67-and-k47-capsules.81968/

CK12 is very much its own beast though - structurally complex, as you could see in that article, and from what i understand, VERY difficult to tune consistently / reliably (large variability of the frequency response).

 

[soliloqueen]

top tier capsules are really hard to make, but that's not why a lot of clone mics aren't good. the answer is acoustics, primarily. Only a few makers genuinely pay attention to how the sound travels around and through the mic body. i've seen more people than i can count iterate on small part changes and capsules for years or even decades trying and failing to electrically engineer out an obvious headbasket issue. If you put a $30 chinese capsule into an actual u87 body, it will sound more like a u87 than a mild majority of boutique clones. People seriously underestimate the importance of this.

 

[Emmathom]

I think someone on the group has already asked : in safe environnements why not take the headbasket off and leave the capsule naked just for the recording time ? What would be the pro's ans con's ?

 

[soliloqueen]

I think someone on the group has already asked : in safe environnements why not take the headbasket off and leave the capsule naked just for the recording time ? What would be the pro's ans con's ?

The basket is a faraday cage that prevents electromagnetic interference. When you take it off, the interference is too loud to use the microphone

 

[MicMaven]

The basket is a faraday cage that prevents electromagnetic interference. When you take it off, the interference is too loud to use the microphone

Yes, no argument. ... and yet, ... ahem ... perhaps the question could be rephrased: What if we minimized the headbasket as much as possible? What is the least massive, least physically intrusive (for want of a better word) headbasket possible? I wonder how minimal could it be while providing the required electromagnetic shielding? Just how "naked" can we make it? OR, have we gotten as close to that as possible already? Can we do more? Has the last word been written?

I think it is a fascinating inquiry. James

 

[Khron]

I wonder how minimal could it be while providing the required electromagnetic shielding? Just how "naked" can we make it?

C414? C12?

 

[Deadly Mix]

What if we minimized the headbasket as much as possible? What is the least massive, least physically intrusive (for want of a better word) headbasket possible?

Shrinking the basket wouldn't like solve the issue. In fact, it could possibly make it worse just as easily as fixing the issue.

I have limited knowledge on mic building, but extensive knowledge on sound itself.
With the "walls" so close you're already looking at reflections likely in microseconds (ųs). So it's not like room acoustics, but more of a resonance combining with the direct signal. The basket is thin so these would be pretty much isolated to the upper frequencies where the timbre of the voice is. In that case, just about anything you do to the basket is going to have some affect and so the trick would then more likely revolve around tuning it to combine with the total sum of the voice, space, body, capsule, basket, electronics in the mic, preamp, etc. or at least what you have control over (mic design and parts) to find just the right design for it to benefit the overall sound.

I would guess that the only feasible way to find the right basket design would be to experiment with a prototype making very small tweaks to the angle, mesh pattern, materials, distances, etc.


I'm expecting some of the seasoned mic designers here to correct me where I'm wrong here.

 

[Deadly Mix]

If you put a $30 chinese capsule into an actual u87 body, it will sound more like a u87 than a mild majority of boutique clones. People seriously underestimate the importance of this.

THIS is what I was thinking, which has kept me from buying any of the cheap mics I've seen mentioned as "donor bodies" for this U47fet I wanna build.
I'm willing to spend a little more to ensure I'm happy with the results and I've never liked Warm Audio, Stam, GAP, etc. So, I expect to have to do some digging for a body and basket that match the original specs.

An artist is trying to build a good tracking studio at home to save some money and just send me the tracks for mix/master/Atmos. The Sterling Audio mic he bought has this resonance to it. He thought it was the room, but after I messed with it a bit, I was thinking the basket was the cause.

 

[MicMaven]

Shrinking the basket wouldn't like solve the issue.

Good day! Thanks for the reply.

I wonder, however, whether there are other ways to minimize the basket without shrinking it. What if it was larger, with larger gaps between the grill mesh? What if the grille was made of thinner mesh? What if we used a different shape? What if we altered the mesh weave pattern? Minimal may not necessarily entail being smaller.

Of course, this may be a purely rhetorical, academic question, as I sorta, kinda presume microphone design engineers have considered these and many other notions, and have already arrived at optimal designs, with what we consider standard grille size and materials for good and tested reasons, but I find the topic interesting and I may experiment with various wire mesh materials solely for my own edification to satisfy my curiosity.

Thanks for playing along! James

 

[Deadly Mix]

I find the topic interesting and I may experiment with various wire mesh materials solely for my own edification to satisfy my curiosity.

I would start by comparing your cheapest low-grade LDC with something along the lines of a U87 or better. There might be something useful to learn in comparing the mesh and design that could help you form a better hypothesis for you experiments.

 

[RosettaStoned]

Good day! Thanks for the reply.

I wonder, however, whether there are other ways to minimize the basket without shrinking it. What if it was larger, with larger gaps between the grill mesh? What if the grille was made of thinner mesh? What if we used a different shape? What if we altered the mesh weave pattern? Minimal may not necessarily entail being smaller.

Of course, this may be a purely rhetorical, academic question, as I sorta, kinda presume microphone design engineers have considered these and many other notions, and have already arrived at optimal designs, with what we consider standard grille size and materials for good and tested reasons, but I find the topic interesting and I may experiment with various wire mesh materials solely for my own edification to satisfy my curiosity.

Thanks for playing along! James

If you don't care about aesthetics, you can build a faraday cage as large as you want with basic chicken wire etc..., just be sure to connect the cage to ground.
-d