KM84 DIY Body & PCB kit – CLOSED

Help Support GroupDIY:

JMan

Well-known member
Joined
Oct 26, 2019
Messages
312
Location
Chicago
Powder coating on the threads did occur to me, so I took a look after my last post. It was indeed preventing a good connection, so I tried to carefully scrape it without damaging the threads. Seems to be better now, although family time has taken my attention in the meantime and I haven’t gotten to plug the mic back in and see if I’ve eliminated the hum or not.
 

waltzingbear

Well-known member
Joined
Jan 30, 2006
Messages
66
Location
Portland, Oregon
The body tube is brass, it will tarnish. There are no gas tight connections in the ground connection path.
thats not to say it won’t work for many years, but remember later when you get odd behavior to clean the path.
 

JMan

Well-known member
Joined
Oct 26, 2019
Messages
312
Location
Chicago
FWIW, I had a few spare minutes just now, so I plugged in the mic that had the hum issue to test it out. Looks like removing some of the powder coating from the threads really did help. No noise at all now!

So thanks to all of you who offered help! I've now got two working, great-sounding mics.
 

59flame

Well-known member
Joined
Nov 28, 2014
Messages
101
anyone have a few extra .1uf wimps MKS0D031000C00KSSD for sale. I could use a few here in the states
mouser seems to be out.
 

kato

Well-known member
Joined
Aug 16, 2004
Messages
1,574
Location
Indianapolis, USA
Anyone else need to drill out the PCB to make the turrets fit?

No one's mentioned it so I'm wondering if Digikey send me the wrong part #?
 

JMan

Well-known member
Joined
Oct 26, 2019
Messages
312
Location
Chicago
Anyone else need to drill out the PCB to make the turrets fit?

No one's mentioned it so I'm wondering if Digikey send me the wrong part #?
I found the turrets to be extremely tight to get in. If they say they’re the right part # and look like they are a close fit, but are just difficult to get started, I’d guess you have the right ones.
 

Banzai

Well-known member
White Market Member
Joined
Apr 6, 2013
Messages
972
Hole is meant to be smaller than the turret as it's a press fit. But if very difficult to install, you can use a round file to slightly enlarge the holes.

Need to be careful though as it's easy to remove too much material and end up with loose turrets. Don't use too much pressure.
 

corgan4321

Well-known member
Joined
Nov 30, 2008
Messages
133
Location
Brooklyn, NY, USA
Only McIrish posting here has built kits from the 4th batch. Others like Corgan and Craigmorris don't have kits from 2021. So we're not going to question the quality of a large batch because of the results of one or two people.

Of course it's possible some people end up with problematic capsules or transformers. Nothing is 100%. The way to resolve those issues is to get in touch with us, like you would with any other product.

But it's also impossible to satisfy everyone and not every negative comment is automatically a manufacturing problem.


Encouraging people to experiment with their builds and try different parts is not being defensive. There's no strategy here, nor do I want one.


Read between the lines: he never built the kits, let alone compare them or build an adapter.

If you disagree, feel free to explain how you build kits without PCB's:

View attachment 84342


Overtly dickish tone is a better description.

"Thanks for saving me hundreds of euro's because your mic sounds horrible" ???

... and you want me to be polite and considerate?


Bad assumptions. We don't sell anywhere near enough kits to live from this, and as demonstrated above, some of these people are trying to influence opinions.

Otherwise this kit has no marketing. Only user reports from members of this forum.


No microphone expert would say all that. You're confusing two different things:

1. The capsule decides what quality CAN be achieved.
2. The circuit, tube, transformer, power-supply etc decide what quality IS achieved.

Everything enters the mic through the capsule, which makes it the only part along with the headbasket that can set the maximum attainable quality and resolution of a microphone. Everything else behind it has to work with what the capsule provides.

But what is your pre-amp connected to, the capsule or the transformer?

Commercial microphones aren't designed around fixed circuits either. Circuits are a toolbox, designed to fit and control the parts around them. You can adjust and change circuits. You can add and remove parts, add EQ filters, adjust sensitivity, add pattern controls etc. Looking at a circuit as this immutable and useless object is a complete waste of opportunity.

And no, your Neumann K87 capsule in a cheap Chinese mic won't sound like a good mic. It'll be unbalanced and probably unusable. But the proper U87 circuit and transformer with a cheap K67 will sound like a U87. Won't be a great one, but it will have the right character.


Neumann is in the thread title to credit them as the source. We didn't create the KM84 circuit. We can change it to something else, it's not important.

Being vulnerable to criticism isn't a problem either. Critique from people who build the kits is welcome and that's how all products are improved. But we could do without the "input" from people who have no intention of building this kit, in a build thread...


Stated the circuit can be used to adjust the frequency response, and each transformer type affects the frequency response of the mic differently. Both statements are true.

If they have no effect on sound, then why bother building a KM84 circuit? Why not just build a generic flat circuit with a flat capsule?

Or every time you don't like something in a mic, you're just going to endlessly swap capsules until it sounds right? How much money are you made of?!


No returns. It's a DIY kit.

Not liking the sound of your build, or kit not matching expectations is not a bad capsule problem.

Problems with sound where your 1st capsule is wildly different from your 2nd is a bad capsule problem. Both your capsules showing problems and being unusable is a bad capsule problem (that includes anything from not working to having poor frequency response)


Then you might as well buy from Stam instead of building anything on this site. For most people DIY is about the process. It's about making something yourself. Not everything is about money.

(can we please leave this thread for those who are building the kit? Anyone who wants to discuss the validity of this project or marketing strategies, take it to the white-market thread)

I'm moving my response to some of the discussions going on in the build thread to this forum per the request of Banzai.

I think Urskov's post on the build thread was worded well and brought up some important points. It's strange to weigh in on a project that you haven't built (RuudNL). It's also bad behavior to misquote somebody (I searched the forums and found no indication of anybody besides Banzai saying, 'Thanks for saving me hundreds of euro's because your mic sounds horrible').
It's totally valid for someone to voice their opinion on this forum. It's also okay if that is a dissenting opinion. It's not okay for anybody to bully somebody privately and, overtly or not, cause them to remove dissenting opinions from the forum either. It's a bad look on somebody trying to sell something and might go against forum rule #4.

Regardless, as far as the actual build goes. You have marketed the product as a "Neumann KM84... ...DIY kit". The circuit is identical. The transformers play a big part in the sound made clear by the few options people have used, however we know that the Cinemag transformer that many used in this build has produced fantastic results in other microphones. The capsule is of a different design to a KK84, and more akin to other SDC capsules from China that are so prevalent based on the backplate design and the frequency response. It's reasonable to assume that the capsule is the weakest link here. If you read just about any article by Klaus Heyne, you will see that he spends a remarkable amount of time altering even the best vintage German capsules. Here's a great article here: Interview: Klaus Heyne, Master Of Microphone Modifications - Page 4 of 6 - ProSoundWeb

I have 7 of the Maiku capsules from this kit. None of them exhibit frequency responses similar to a KK84 capsule. They also vary in sensitivity by around ~8-9db. I posted my findings in the other thread with my REQ curves. That's pretty bad quality control by any measure. It makes me wonder about the quality of the gold sputtering, or the tensioning of the diaphragm, or the thickness of the diaphragm substrate, none of which we have any data for.

I have no problem spending time altering these kits to my liking (It's fun) but maybe some other users do. Maybe some were happy enough with the kit as is. I was interested in the kit because it was marketed as a "Neumann KM84... ...DIY kit". I think most people who are upset are upset because the capsule you included in the Neumann KM84 kit doesn't hold up to the brand association you invoked. Also, when they voice their opinion, you (Banzai) are are sometimes responding in a distastefully defensive manner. I will continue to enjoy tailoring these microphones I have to my liking as best I can because it's fun for me, but I won't be interested in any future projects you're involved in marketing.
 

Banzai

Well-known member
White Market Member
Joined
Apr 6, 2013
Messages
972
I'm moving my response to some of the discussions going on in the build thread to this forum per the request of Banzai.
Thank you!

I think Urskov's post on the build thread was worded well and brought up some important points. It's strange to weigh in on a project that you haven't built (RuudNL). It's also bad behavior to misquote somebody (I searched the forums and found no indication of anybody besides Banzai saying, 'Thanks for saving me hundreds of euro's because your mic sounds horrible').

It's totally valid for someone to voice their opinion on this forum. It's also okay if that is a dissenting opinion. It's not okay for anybody to bully somebody privately and, overtly or not, cause them to remove dissenting opinions from the forum either. It's a bad look on somebody trying to sell something and might go against forum rule #4.
I sent my reply by PM to Urskov before posting it, so he could read through it and see for himself whether the general impression he had of a "bad batch" was accurate. That's not bullying.

In a previous thread he had told me he was a marketing professional, so in the original post there was a joke reference to his "lizard marketing brain" – because in each of my actions he always sees strategy, business, and $'s. Same problem with a few others, who don't see any of my suggestions as helpful, but always as defensive.

I have no strategy and there is no defense.

My concern is for everyone building this kit. Not any one individual person on their own. There are easy solutions for some of the issues you have and others might have as well. Just sharing experience and the experience of others.

Regardless, as far as the actual build goes. You have marketed the product as a "Neumann KM84... ...DIY kit".
I understand.

It's also a €100 kit. Aftermarket SDC capsules on their own are sold for more than the price of this entire kit. There has to be reasonable expectations when embarking on a project.

The circuit is identical. The transformers play a big part in the sound made clear by the few options people have used, however we know that the Cinemag transformer that many used in this build has produced fantastic results in other microphones. The capsule is of a different design to a KK84, and more akin to other SDC capsules from China that are so prevalent based on the backplate design and the frequency response. It's reasonable to assume that the capsule is the weakest link here. If you read just about any article by Klaus Heyne, you will see that he spends a remarkable amount of time altering even the best vintage German capsules. Here's a great article here: Interview: Klaus Heyne, Master Of Microphone Modifications - Page 4 of 6 - ProSoundWeb
In any €100 kit, the capsule will always be the weakest link. No-one is arguing or denying it. Pictures of the capsule taken apart have also been posted in this thread for years. Never been a secret.

What seems to be the problem here, is that any suggestion that the circuit and transformer can be used to improve the frequency response is taken as "the circuit and the transformer are the problem!". I have never said that.

I keep repeating these microphones are a sum. With different combinations of circuit settings and transformers, the results will be different. You might like them more than your current results.

Please have a look at this chart I've posted on this forum before. This is 3 identical type transformers, from 3 different brands:

transformer comparisons.png

None of them sound the same. The AMI exhibits no roll-off in the highs, and the Cinemag no roll-off in the lows. Both have different mids. These are extremely noticeable differences, not minor differences you will have problems hearing.

Both are copies of the original Haufe in green.

With these transformers, if you wanted more lows, you would use the Cinemag. If you need more highs, you would use the AMI. Because you can use transformers to tune your builds. That's not the same as "the transformers are the problem!".

In short, obsessing over one component instead of looking at a microphone as a whole, is a wasted opportunity.

I have 7 of the Maiku capsules from this kit. None of them exhibit frequency responses similar to a KK84 capsule. They also vary in sensitivity by around ~8-9db. I posted my findings in the other thread with my REQ curves. That's pretty bad quality control by any measure. It makes me wonder about the quality of the gold sputtering, or the tensioning of the diaphragm, or the thickness of the diaphragm substrate, none of which we have any data for.
I understand.

Your capsules are also 3 years old from the 1st production batch. Do you think it's fair to present your findings as if they're from the 4th batch in 2021? We have made improvements over the years, especially in consistency. I'm sorry you couldn't benefit from that.

That doesn't mean either that the current batch will be 100% perfect. That is something we will probably never reach, which is why we have support available.

Over the last 3 years, anyone who has contacted me about discrepancies in capsules, has always been offered the same solution: send me your microphones, and I will match capsules to your builds. Every person has always accepted the solution, and been very happy with the results. We have never charged for this, or demanded a "matching fee".

Same offer was made to McIrish: send me your microphone, we'll check the transformer and capsule to make sure they're working properly, and then we'll match a capsule to your build.

I have no problem spending time altering these kits to my liking (It's fun) but maybe some other users do. Maybe some were happy enough with the kit as is. I was interested in the kit because it was marketed as a "Neumann KM84... ...DIY kit". I think most people who are upset are upset because the capsule you included in the Neumann KM84 kit doesn't hold up to the brand association you invoked.
I understand, and apologise to anyone who is disappointed by the performance.

Also, when they voice their opinion, you (Banzai) are are sometimes responding in a distastefully defensive manner.
I understand, but also don't agree with your impression. I don't respond distastefully or defensively to anyone building or owning this kit. We have a responsibility to all of you.

I have responded dismissively or distastefully to people who do not own and will never build this kit. It might seem as if these are my first interactions with these people, but they aren't. There's a repetitive pattern of the same people always getting involved, and to put it politely, always looking to start fires. You even witnessed one of them fabricating stories just to add fuel.

At some point, everyone reaches their own personal limit and they have to put an end to it, regardless of how it makes them come across.

See Urskov's initial post for the impression the entire 4th batch is bad. Is that a fair impression to have? He didn't arrive at that conclusion on his own.

I will continue to enjoy tailoring these microphones I have to my liking as best I can because it's fun for me, but I won't be interested in any future projects you're involved in marketing.
I wish you all the best and hope you do have fun.

Maybe what isn't fair in your conclusion, you haven't bought your kits from me. It's possible your experience would have been different if you had.
 
Last edited:

Urskov

Active member
Joined
Jan 6, 2020
Messages
31
Location
Dnk
I want to sincerely apolegize for the brainfart that was the statement that it was a "bad batch". Of course I had no way of knowing that 200 capsules were all bad based on the little documentation in the thread. I meant to say that the capsules seemed to be the issue in the specific cases mentioned in the thread. Perhaps, reflecting on it now, they were just simple cases of too high expectations. I'll come back to that.

Honestly, retrospectively, I don't know why I spent so much energy on trying to criticize a kit with a very reasonable price directed at the DIY community. So to remove all notions of me being bullied into silence. Banzai only offered me to come to my senses, which I have done now, I think. I first deleted the post it because I was kind of ashamed that I put so much energy into it, not even really wanting to build the kit. I guess it's because I come from DIY pedal community that are extremely critical and zealous when it comes to snakeoil salesmen - which you aren't, btw, Banzai, don't get me wrong. It's just the critical culture I take with me and - too many boutique builders trying to cheat naive musicians - and my personal "sense of justice" (said with air quotes...).

Anyway, you misremembered (and I take your word for the namecalling being a joke, after all it's hard to decipher people's tone of voice when it's written). I work in communications (not-for-profit public healthcare), not marketing. I fucking hate marketing language and hyperbolic blurbs designed to induce GAS. My main critique is not about the money, but, as it also was in the other thread about the LDC capsules, about transparency. The source of the components, the actual work undertaken before it is sold etc. People are usually very forward about this in DIY circles. This is not to suggest that you shouldn't get something out of being the middleman ensuring we can get a huge, steady supply at a better price instead of multiple smallscale groupbuys. That's the whole spirit of this forum. But to ensure my fellow DIY'ers aren't duped (again, the "culture" from DIY pedal pervades here). I'm not saying you are, but there appeared to me - my research into the whole thing might have been too superficial in the 20/20 hindsight - to be misinformation going on.

You say that there have been multiple visual teardowns of the capsule revealing the differences from the Neumann-original - OK, I didn't catch that and so didn't alot of the other people responding to the thread, including buyers, it seems. So some, including me, did get the idea the capsule is a closely modelled after the Neumann. I was actually interested and wanted to poke around to see if all the capsules were like this. I know you don't advertise it as a "Maiku KK84 capsule", so I can't fault you for that. But I hope you can see how the whole naming of Neumann in the sales thread name can be misinterpreted, especially if people are too lazy to click through the threads and see stuff like those teardowns.

Also, I need to add, they do sound from what I can tell, and like many of your champions have already confirmed, decent - not harsh like so many stock capsules - and if the capsules are ever available to buy alone, I would buy them in a heartbeat to stick on cheap donor mics or something. Because you're right about one thing, I'm cheap... I'm a self-recording, multi-instrumentalist musician, not a big circuit-analysis guy, pro audio gear is secondary tools... so I constantly chase the ultimate bang for the buck. As for the whole kit, it's not for me, partially because of good commercial options in the price range (as I mentioned), limited time for DIY'ing right now and so on, but it obviously is for others. So good for y'all and enjoy it. Don't listen to my cheapness talking, it's not what DIY is for for most people.

Also what I meant by "defense strategy" wasn't anything remotely like a "calculated business strategy". What I meant is simply to reflect on the effect your response has in terms of escalating or deescalating the debate. I think - here I am again giving communication advice, sorry if it's patronizing - you can easily deescalate future debates about the quality. Just look at how fripholm handled the potential distrust of his product spreading like a wildfire here: [BUILD] fripholm's TG1 Zener Limiter boards - support thread
Simple, assuring, responding quickly instead of going head to head.

I know the case was a bit different here... some of the posters were out for blood (I weren't, though I can understand how it can be interpreted that way). Then don't dignify them with a response... Or tear their claims down by questioning their methods in a non-aggressive way instead of belittling. Or grab the bull by the horns and be honest, like you ended up being here - "you guys are expecting to much out of a 100 euro kit". It's true, I see that now. But some were expecting KM84 sounds out of the kit. That could've been dismantled very easily.
I'm not saying you should be doing costumer service - you're merely making these kits available and you, as you say, didn't create the "Build"-thread. You're not expected to do much in the way of offering help - which you still are, though, and that's great. Offering the returns to the few extremely dissatisfied, hard-to-please costumers that might pop up every once in a while is also a very good gesture and I applaud you for doing it.

That's about all I have to say about this matter from here till eternity. I already feel nauseous for spending so much energy on it. I wish you good luck on the sales and hope I can remember to think twice next time I want to enter in heated debate. I agree with some of the people defending you that it should be about the spirit of DIY (counting work hours, components etc., DIY doesn't save you money in the end as is so commonly said).. and ultimately about the music being captured with the things that we have fun creating.
 
Last edited:

kato

Well-known member
Joined
Aug 16, 2004
Messages
1,574
Location
Indianapolis, USA
Don't feel nauseated that you put a lot of thought into this. We're all humans with feelings and we all experience the same highs and lows from DIY. And if I were Corgan, 7-capsules deep, I too might feel a little salty if I thought I'd been misled.

I think many of us (myself included) read into "Maiku capsule" as if it were somehow superior. I think we all projected what we wanted to believe: that his capsules were somehow Neumann-ish. But looking back, neither he, nor Banzai, claims he does any QC on them. Perhaps it would have been more transparent to call them "Maiku-imported" capsules or something.

Once aligned with that reality, I was satisfied that Banzai offers a replacement in the off chance we get a dud. And I feel pretty optimistic that this mic has the potential to sound good.

I might be one of those people you identified as being on Banzai's side. It's true. I thought one person in particular was being needlessly unfair. But I'm also on your side. I too am a home recording multi-instrumentalist with a practical-minded budget. (I also build a lot of stompboxes, do comms work for a non-profit, and I also hate marketing speak. Nice to meet you!)

If I had an immediate need to record some acoustic guitar or hi-hats, I'd probably look into the LCT 140 AIR and "get her done" for a quick $150. But ultimately, I'd feel more happy with a self-built KM-84ish mic that I could work on myself, knowing it wasn't full of smd components.

I'm glad you spoke up, if nothing else, for the sense of community. Since you're from Stompboxland, you probably know Jon Patton. He's here as Midwayfair.

Matthew (currently building the Meatsphere from MusicPCB.com)
 
Last edited:

Martan

Active member
Joined
Nov 9, 2019
Messages
37
Hi all,

I bought a pair of these and thought it was a great diy project. Thanks to Bonzai for doing this and also thanks for his patience as diy frustration played out (as it sometimes does). I like the sound of both my builds yet have the same issue some have found that the capsules are 8-9dB apart in response. I can compensate at the preamp, but was wondering if there is a solution for the discrepancy in the capsules. Can we measure capsule capacitance and members exchange capsules with each other to get a match? I've done stranger things to complete a diy project. No worries from me. It's part of the diy game. Would just like to know (if there is one) an objective measurement to match capsules and get my pair matched more closely. Again, thanks again for all the info from everyone.

All the best,

Marty
 

Banzai

Well-known member
White Market Member
Joined
Apr 6, 2013
Messages
972
Hi all,

I bought a pair of these and thought it was a great diy project. Thanks to Bonzai for doing this and also thanks for his patience as diy frustration played out (as it sometimes does). I like the sound of both my builds yet have the same issue some have found that the capsules are 8-9dB apart in response. I can compensate at the preamp, but was wondering if there is a solution for the discrepancy in the capsules. Can we measure capsule capacitance and members exchange capsules with each other to get a match? I've done stranger things to complete a diy project. No worries from me. It's part of the diy game. Would just like to know (if there is one) an objective measurement to match capsules and get my pair matched more closely. Again, thanks again for all the info from everyone.

All the best,

Marty
Hi Marty, sorry about the issue with your capsules. You can send your mics over to me and I'll match them for you.

If you prefer a faster DIY solution, you can remove C2 entirely from the mic that is lower in volume. Then adjust the value of C2 in your louder mic. Higher pf = lower sensitivity (4pf = ~ 3dB pad)
 

Latest posts

Top