New to the world of Microphones and could do with some nudges in the right direction.

[carboncomp]

Hello.

I'm new to mics, but have some basic knowledge of analogue electronics through DIY guitar and amp projects.

Would love to dip my toe into making a vocal mic, and would love some advice on what circuits to look at. I don't really want to go down the kit path as I have many components and can whip up a PCB board to fit a donor housing no problem.

So, what should I be considering for a first project, for a phantom powered vocal condenser mic?

I have seen the term 'Alice mic' thrown around in a few places and on youtube, good starter, or with looking at something else?

Thank you for taking the time to read.

 

[Whoops]

So, what should I be considering for a first project, for a phantom powered vocal condenser mic?

You should do an U87 project, there's pcbs for it, bodies and all parts are available, a lot resources for it and you can get help over here
In the end you will have a top quality vocal mic and not just a DIY gizmo.

check these pages, everything you need is over there:

http://www.vintagemicrophonepcbkit.com/DU87.html
https://groupdiy.com/threads/neumann-vintage-u87-clone-build-thread.48030/
https://groupdiy.com/threads/vintag...-pcb-kit-for-diy-new-d7-custom-capsule.49675/
https://groupdiy.com/threads/syt-5-microphone-bodies-b-stock.79952/
https://groupdiy.com/threads/unmark...parts-syt-5-cu-49-ht-11a-gt-2b-and-u47.50015/

I have seen the term 'Alice mic' thrown around in a few places and on youtube, good starter, or with looking at something else?

I remember a long time ago the "Alice mic" it being a popular project in mic builders yahoo group, not at all over here. If I remember correctly it used an inexpensive Electret capsule, so not even true condenser.
A lot of time has passed and nowdays there's much more interesting and better projects that will actually turn out into high quality professional microphones, like the U87 project I suggested

 

[kingkorg]

This mic from @rogs is exceptional and relatively easy project. You can go with both electret and externally biased capsule.

http://www.opic.jp137.com/
While u87 project whoops suggested is very exciting project there are two quite tricky parts to pull off, biasing and feedback network tuning. Make sure you are familiar with these two parts before starting the build.

 

[Ricardus]

The U87 build is highly recommended. I did it. You can do your own boards if you want to.

Someone else here took a Neumann KM84 circuit and adapted it to a large diaphragm condenser. I plan to get around to doing some of those as well.

If you want to be really daring and feel like doing some point to point wiring you could do a classic tube mic clone. U47 or something cool like that.

 

[carboncomp]

This mic from @rogs is exceptional and relatively easy project. You can go with both electret and externally biased capsule.

http://www.opic.jp137.com/

That looks like just the sort of thing I'm after, love any project that starts with stripboard! Thank you.

Someone else here took a Neumann KM84 circuit and adapted it to a large diaphragm condenser. I plan to get around to doing some of those as well.

Thank you, I will look into that!

 

[Purplenoise]

The u87 was my first mic build. It gave me a couple of headaches but all the answers are here in this forum and members are very helpful…and very knowledgeable. The mic came out great…I have learned a lot…and since then I have built more than ten more of various types. Dany Bouchards boards are a great way to start and very well documented ( vintage mic pcb)

 

[Khron]

You should do an U87 project, there's pcbs for it, bodies and all parts are available, a lot resources for it and you can get help over here
In the end you will have a top quality vocal mic and not just a DIY gizmo.

While u87 project whoops suggested is very exciting project there are two quite tricky parts to pull off, biasing and feedback network tuning. Make sure you are familiar with these two parts before starting the build.

I would argue the even trickier part will be getting your hands on a K87 capsule with isolated backplates.

The FET847 or Alice, or the @rogs mic that @kingkorg suggested would have far more easily achievable positive results, i would say.

 

[mhelin]

Whatever you plan to do please don't waste your time building another DIY cheap mic using cheap £20 China capsules from Ebay and acoustically not so good 'donor' bodies (ant the most common Schoeps circuit used to death of course) unless you want just practice soldering. Instead take your time studying which capsule design you might like sonically and what proven designs (like the one mentioned in this thread) might fit your bill. I would vote a proper sized body (see lifelongmusic-uk in england for an example), could be U67/87/47, Maiku K47 capsule is a good one, 3U Audio's as well, (there are others, but I would avoid K67/87 type capsules as they need some correction circuit and even then it's difficult to get the circuit match the exact capsule. The op-amp Alice circuit or @rogs OPIC might indeed work well or better than a regular discrete FET circuit and doesn't need biasing adjustments, instead of following the circuit as it is you could try adding output transformer to it.

 

[carboncomp]

I would argue the even trickier part will be getting your hands on a K87 capsule with isolated backplates.

Just to double-check, an isolated backplate is one with the brass plate rather than exposed film and is what make it cardioid?

 

[soliloqueen]

Just to double-check, an isolated backplate is one with the brass plate rather than exposed film and is what make it cardioid?

ok, quick rundown. a multi-pattern capsule is actually two cardioid capsules back to back (basically, there is some complication to how this is achieved but essentially). patterns are switched by combining the two cardioid signals in different ways.

in a connected backplate capsule, the backplates of the two capsules are connected electrically, and only the membranes on the front and rear are separate, so that's 3 lead wires. in an isolated backplate capsule, the backplates are not connected electrically, and there are 4 lead wires. there is no difference between the two in function (in most cases), but they require two different circuit designs to achieve the same function. connected backplate capsules are more common than isolated ones, because only a few, somewhat unusual circuits like the original u87 use them. it's better for a beginner to start with a project that uses more common capsules.

if you are just making a cardioid mic with a multi-pattern capsule, you don't need to care, because you're only hooking up half the capsule anyway

 

[carboncomp]

ok, quick rundown. a multi-pattern capsule is actually two cardioid capsules back to back (basically, there is some complication to how this is achieved but essentially). patterns are switched by combining the two cardioid signals in different ways.

in a connected backplate capsule, the backplates of the two capsules are connected electrically, and only the membranes on the front and rear are separate, so that's 3 lead wires. in an isolated backplate capsule, the backplates are not connected electrically, and there are 4 lead wires. there is no difference between the two in function (in most cases), but they require two different circuit designs to achieve the same function. connected backplate capsules are more common than isolated ones, because only a few, somewhat unusual circuits like the original u87 use them. it's better for a beginner to start with a project that uses more common capsules.

Thank you, So a single diaphragm = Cardioid.
Whereas a dual-diaphragm can be omni using both diaphragms, super/wide cardioid and finger of 8 by adjusting the bias voltage on one side?

And if so, on say this project:
http://www.opic.jp137.com/index-ldc.html
It is designed for a single cardioid capsule, but I could use a multi-pattern capsule and change the polar pattern by just adding a voltage divider on the DC voltage multiplier? Or would I need a totally different circuit or 2 of the Op Amp impedance convertor circuits, or would 2 only be needed if I was going for stereo output?

Sorry, a lot of questions there.

 

[doqmemory]

So a single diaphragm = Cardioid.

For an LDC (Large Diaphragm Condenser), that is true, but sometimes other types can be omnidirectional (for instance, with small diaphragm, such as in a "pencil mic").

I recommend that you start with a cardioid-only microphone, since that's what you are likely to use most of the time for vocals. If you enjoy making and using it, then next try a multi-pattern one. You might eventually want to try a tube microphone, but you should get plenty of experience first, since the voltages in a tube microphone can be lethal.

I recommend the FET847 or Pimped Alice as your first project., to see if you like it.

Beware, though, it is an addictive and expensive hobby! I could have purchased several vintage M49's for the amount that I have invested in microphone parts in the last few years.

 

[Whoops]

I would argue the even trickier part will be getting your hands on a K87 capsule with isolated backplates.

Not tricky at all 3U Audio does it, plus some other sources.
But I would get it from 3U

 

[carboncomp]

Rather than starting another thread, I guess I should ask this in case anyone else stumble across it and has the same question.

If I wanted a vocal mic that would also be good for duet live use, I'm guessing figure 8 would be the best to take advantage of the null area, I would need a 4 wire capsule for this right, and flip the polarity on one side?

That way I could toggle from cardioid to figure 8 by engaging and disengaging the power to the reversed polarity side?

 

[swpaskett]

Perhaps I am just being a wet blanket; I don't want to be, in fact, I have a couple mic projects on the back burner myself. What I do not see in the mic builder community is moderation of expectations. Yes, we can build mics that look like U87 clones and we can do listening tests and tell ourselves (and we are all totally objective, of course) that our mic sounds so much better than a U87. But we cannot objectively test it without recourse to test facilities that exceed the cost of the homes most of us live in. Most of us cannot machine parts. We cannot measure polar response. We cannot produce calibrated test tones or sweeps.
I would never show up at a live sound job with a homemade mic mostly because I am not convinced it could survive in that environment, but also because it smacks of being unprofessional, though I have used plenty of other homemade gear. I suppose in a studio setting where you can have do-overs it is a different story. So maybe I am just being fickle. Or a wet blanket. Not trying to kill discussion and I respect the guys brewing their own and learning new things. I just rankle at some of the claims, and that has nothing to do with the OP or other posters on this site. So why am I saying this? Just a rant, I guess.

 

[ccaudle]

I would need a 4 wire capsule for this right, and flip the polarity on one side?

You can also do it with a 3 wire capsule, assuming you can generate the proper voltages for the diaphragms. Look at some of the classic switchable pattern microphones in the technical documents forum to get an idea how it is done.

 

[carboncomp]

Perhaps I am just being a wet blanket; I don't want to be, in fact, I have a couple mic projects on the back burner myself. What I do not see in the mic builder community is moderation of expectations. Yes, we can build mics that look like U87 clones and we can do listening tests and tell ourselves (and we are all totally objective, of course) that our mic sounds so much better than a U87. But we cannot objectively test it without recourse to test facilities that exceed the cost of the homes most of us live in. Most of us cannot machine parts. We cannot measure polar response. We cannot produce calibrated test tones or sweeps.
I would never show up at a live sound job with a homemade mic mostly because I am not convinced it could survive in that environment, but also because it smacks of being unprofessional, though I have used plenty of other homemade gear. I suppose in a studio setting where you can have do-overs it is a different story. So maybe I am just being fickle. Or a wet blanket. Not trying to kill discussion and I respect the guys brewing their own and learning new things. I just rankle at some of the claims, and that has nothing to do with the OP or other posters on this site. So why am I saying this? Just a rant, I guess.

Dont worry, I have very low expectations of anything I build myself

 

[Gus]

The electronics are the easy part(copy paste "design") the acoustics(capsule grill etc interactions) are the harder part, as swpaskett posted how many people would know how or can do useful measurements?

That said if you just want to build something there are lots of circuits to copy and capsules to buy(how good they are are often directly related to price) and bodies you can buy or you could build your own bodies.

There is a lot of nonsense on the web about microphones so question every thing you read, after sometime you might find some peoples posts that you might trust after doing your own testing.

Read all the microphone posts at this forum some are good.

You have it easy now in 2022, in the 2000's and earlier it was harder to find information and parts for microphones now if you search the web you can find all kinds of information.

 

[kingkorg]

Perhaps I am just being a wet blanket; I don't want to be, in fact, I have a couple mic projects on the back burner myself. What I do not see in the mic builder community is moderation of expectations. Yes, we can build mics that look like U87 clones and we can do listening tests and tell ourselves (and we are all totally objective, of course) that our mic sounds so much better than a U87. But we cannot objectively test it without recourse to test facilities that exceed the cost of the homes most of us live in. Most of us cannot machine parts. We cannot measure polar response. We cannot produce calibrated test tones or sweeps.
I would never show up at a live sound job with a homemade mic mostly because I am not convinced it could survive in that environment, but also because it smacks of being unprofessional, though I have used plenty of other homemade gear. I suppose in a studio setting where you can have do-overs it is a different story. So maybe I am just being fickle. Or a wet blanket. Not trying to kill discussion and I respect the guys brewing their own and learning new things. I just rankle at some of the claims, and that has nothing to do with the OP or other posters on this site. So why am I saying this? Just a rant, I guess.

I rely almost exclusively on measurements when i do my builds, all of which can be made at home. You absolutely do not need anechoic chamber and such. Even real Neumanns are not QC-ed in anechoic chambers. There is a learning curve though, and some research to be done. However i do agree that most blindly copy the designs and hope for the best. I do claim there is no way one can build a u87 replica without doing some serious measurements and adjustments having original u87 reference material to compare it to.

Spoiler alert:
Even with all the resources and measurement equipment i could never match all aspects of the original u87. IMHO c12, elam251, u47 are piece of cake compared to u87 and u67.

 

[Purplenoise]

Perhaps I am just being a wet blanket; I don't want to be, in fact, I have a couple mic projects on the back burner myself. What I do not see in the mic builder community is moderation of expectations. Yes, we can build mics that look like U87 clones and we can do listening tests and tell ourselves (and we are all totally objective, of course) that our mic sounds so much better than a U87. But we cannot objectively test it without recourse to test facilities that exceed the cost of the homes most of us live in. Most of us cannot machine parts. We cannot measure polar response. We cannot produce calibrated test tones or sweeps.
I would never show up at a live sound job with a homemade mic mostly because I am not convinced it could survive in that environment, but also because it smacks of being unprofessional, though I have used plenty of other homemade gear. I suppose in a studio setting where you can have do-overs it is a different story. So maybe I am just being fickle. Or a wet blanket. Not trying to kill discussion and I respect the guys brewing their own and learning new things. I just rankle at some of the claims, and that has nothing to do with the OP or other posters on this site. So why am I saying this? Just a rant, I guess.

Party pooper