Wednesday, May 3, 2017


by Mark King for
12-251 from
Why would you build your own microphone? The first answer is to save money and the second is to get a microphone that sounds like you want it to sound.

Besides looking at building microphones we'll take a look at the basic tools you need for doing electronics and DIY. If you're looking for just the tool information scroll down to the TOOLS section head to see what's needed.

Building your own microphone allows the use of premium electronic components


Lets clarify a little more here, what I'm talking about is building your own large diaphragm condenser (LDC) microphone with vacuum tube electronics for making high quality recordings. The results should compete directly with any microphone on the market regardless of price.

There are four main electronic components that determine the character of any LDC microphone.

1. The capsule

2. The tube used for amplification

3. The output coupling capacitor

4. The output transformer

The shape of the head grille that houses the capsule is also very important, it should transparently allow sound to pass through it while providing galvanic shielding to the sensitive condenser capsule and ultra-high impedance electronics.

The power supply and cabling used to connect a tube condenser microphone are important but they're not nearly as influential in shaping the tone a microphone produces as the four main electronic components and the grille-head shape.


There are basically two different capsule designs for LDC tube microphones, the center terminated style as was used in the Neumann U-47 (and most of their other microphone models) or the edge-terminated style that was used in the AKG C-12 and the Telefunken 250/251 style microphones.

Center Terminated Capsule Design, RK-47 by
Edge Terminated Capsule Design, RK-12 by
Capsules from various brands may look similar but they don't necessarily sound the same at all. The capsules pictured above are made in China and are sold by

More than any other component in a microphone the capsule is the singular most important component that determines the sound-personality of a condenser microphone. 

How capsules are made varies from brand to brand and model to model. There are dozens of brands and models to choose from. Some models attempt to mimic the classic AKG and Neumann styles of construction as closely as possible. This requires very precision equipment to mill the metal work to extremely precise tolerances. This machine-shop work can be done by a human running a mill or it can be done by a CNC machine. How accurately they adhere to the original design directly affects the sonics of the product. 


The internet has made acquiring parts from around the world much easier. Now you can select from the best boutique components available by a handful of the world's finest craftsmen. These components are not inexpensive but when you consider that the original microphones that utilized similar components regularly sell for $15,000 to $30,000 and more, these start looking down right inexpensive. 

Handmade by Tim Campbell in Denmark, beautiful boutique AKG C-12 capsule reproduction
Handmade by Siegfried Theirsch in Germany, the Blue Line M7 style replica skinned with PVC
Handmade by Beez Neez in Australia, their boutique AKG style C-12 capsule

These are just a few of the better known boutique capsule suppliers, there are many more sprouting up all the time.


Never touch the pretty gold diaphragms on a microphone capsule. Never ever! Protect them from solder splatters while you're working on your microphone. The slightest tiniest bit of solder spit will ruin a diaphragm instantly.

Gig-ohm resisters can change in value due to oil from your skin, don't touch them with your bare hands. Overheating them with a soldering iron is also not advised since that can also affect their value. 


When I first saw I thought it was just another vendor trying to push cheap Chinese manufactured goods. After a lot of reading I finally decided to give one of their kits a try, it was their 12-251 model, one of their most complex kit builds. 

I was very impressed with every facet of the mic-parts kit. The build guide was excellent with detailed descriptions and clear color photos. I followed the instructions and built a wonderful sounding LDC tube microphone. I've since experimented with different output coupling capacitors on it and changed it to what we now call "The V-Twin" (based on the twin triode amplifier circuit).

I have owned some very expensive Neumann microphones over the 50+ years I've been recording, none of them have sounded better to my ears than my modded V-Twin. The success of this microphone build led to another kit, then another, then modding microphones I already owned with new capsules and electronics. Warning, building your own microphones can be expensive if you build enough of them.

When you build your own microphone you learn every facet of what goes inside it. If it ever breaks chances are you'll know where to look for problems since you made the entire thing. Building your own microphone is liberating and it removes all the voodoo and unknowns about commercially available products. 


I'm very fortunate, life has provided me with 50+ years of building electronics and I've had the opportunity to listen on many different systems. Nowhere is listening more critically important than in choosing microphone components.


Not all capsules that look the same, sound the same. It sounds simple enough but it's never been more true than looking at Chinese microphone capsules, they may look similar but the sound can be dramatically different from brand to brand. 

Some are skinned with 3-micron diaphragms, some with 5-micron, some with 6-micron and even thicker materials. Some use mylar and exotic models use PVC like the first Neumann M7 capsules used. Sellers often talk about the thickness of their diaphragm material and how it affects the sound. 

I've heard capsules with 6-micron thick diaphragms that have a hard unpleasant edge to their sound, inspite of the fact this is the thickness Neumann uses. I've heard capsules with 6-micron thick diaphragms that sound fantastic, and all points in between these extremes. Through various listening tests I've determined that the thickness of the diaphragm is less important to me than the metal-work a capsule is made from or how well the diaphragm was mounted to the metal work. My personal favorite Chinese capsules are skinned with 3-micron mylar from Japan, these are some of the best I've ever heard. 


I've been going to musical instrument trade shows since 1978 when I attended my first Summer Namm show in Chicago. Trade shows like NAMM, NAB, AES, NSCA and many others have given me the opportunity to meet and chat with lots of interesting people such as Deane Jensen, Leo Fender, Jim Marshall, Les Paul, Bob Moog, Ray Kurzweil, BB King, Neil Schon, John Entwistle, Hartley Peavey, Roger Linn, Dave Smith, Tom Oberheim, Rupert Neve and many other very cool people.

Beware of the used-car microphone-salesman hustling inexpensive imported parts, who talks about how he hangs out with big-guys like Royer and Bock (I've hung out with them too and discussed mic design). Another completely unverifiable claim is how budget capsules track the performance of a vintage Neumann part within 2-dB. Why don't they just provide recordings of their microphones next to the real thing?

Watch out for descriptions that include "we redesigned the metal work for manufacturing efficiency but it sounds exactly the same". There is much more at work than just the frequency response in a large diaphragm microphone capsule. In making capsules, cheap builders often take manufacturing shortcuts that really affect the overall character of sound the capsule produces.

How any company reselling Chinese parts does quality control is extremely important, some companies talk about quality control while others implement it. Let me tell you it's a real bummer to spend your money on a $600 microphone purchased through the internet, then wait for your purchase to arrive only to find out you got a dud and need to pay shipping charges to return it. The reputable sources provide return shipping charges on items if they send you a poorly manufactured or defective unit.

These are just a few of the things to watch out for if you go looking for parts to build your own microphone. 


The metal work on inexpensive Chinese microphones has a big impact on the sound a microphone makes. Take the head-grille off an inexpensive Chinese mic and hold it up to your ear, do you hear the ocean? The head-grille used on many cheap microphones can create a rushing sound similar to listening to a sea shell. The microphone capsule hears that too along with everything else. The head-grille can make the microphone sound boxy or open depending on how much screen is used and how large the grille-head portion is.

Is the capsule in front of just the grille or is is up behind support metal? I've seen inexpensive microphone models where they worked tirelessly to reduce the cost and boost the feature count to attract your buying dollar. These are usually a bunch of cheap, mismatched components cobbled together and passed off as boutique. 

The metal windscreen that surrounds a mic capsule also provides electrical shielding, if you operate the mic with the shield off you'll hear hum and noise that won't be present with the grille/head installed.

I found the best deal I ever got on a new microphone while scanning the internet for donor microphone bodies I could rebuild into my own mic creations. Google is your friend when you're looking for microphone metal work to build your own mic creation. 


The tube makes a difference but in my opinion based on reamping experiments, not as much of a difference as many people make it out to be. By repeatedly playing an identical recorded track, then recording it with microphones with various tubes installed in them we gathered performance data.

I've used this same technique to listen to guitar amplifiers with replacement tubes in them. When all factors are identical except the tube is changed we just could not verify a performance advantage consistently. In statistics, they refer to results like this as random or guesses. All this has led me to the opinion I have today, there is not that big of a difference in the way tubes sound. It's an incomplete study but it is born from years of playing with tube guitar amplifiers and gear in the recording studio.

Back in 2007 I bought a new Peluso 2247LE microphone which had a highly regarded NOS steel Telefunken tube in it. I kept the microphone for three years and then sold it because I never cared for the sound it made. It was not complimentary to my voice or my female partner's voice. 

Experience with that Peluso microphone led me to build and experiment with several microphones using various tubes including the EF86 and vintage N.O.S. Telefunken EF800 (both glass tubes). In my experimenting the capsule, coupling capacitor and output transformer have a much more profound effect on the character of a microphone's sound than the tube used for the amplifying.

The Peluso 2247LE microphone I owned had a very small output transformer in it, so small it fit neatly inside the little steel can used in the cheapest Chinese microphone bodies.

Note the physical size, almost 1.5" square and almost an inch thick
If you look at the components in a vintage Neumann U-47 the output transformer is not tiny, it's a big slug of metal and windings that lives at the bottom of the microphone body. Here is a link to our U-47 schematic copy.

If a manufacturer says their microphone sounds like a vintage U-47 or U-48 then you need to look at the output transformer. If it's a little square Chinese part there is no way it's in the same class sonically as the original BV-8 used in the U-47, they share nothing in common except it's become popular to slap a BV- part number on inexpensive parts to make you think it's the same. 

There is a lot more going on in a transformer design than just the winding ratio. How the windings are segmented, the alloy the metal is made from and the size of the laminations all affect tone profoundly. 
Transformer size comparison by Bock Audio
My intention here is to provide you with an overview of information about building microphones rather than a specific instructions about building any specific microphone. The options for a microphone builder are many and the prices are all over the place.


The tools and equipment needed to build a microphone are the same as those for building any electronics. The great thing about investing in quality tools is, they continue to work for you year after year making new things and repairing old ones. Here's a look at the short list of tools required to build a microphone kit.


A multimeter is a necessary tool for checking wire continuity, checking resister values and measuring voltages in a microphone build. 

Fluke 101 Basic Digital Multimeter

Fluke meters are not the cheapest but they last forever and they're accurate. You don't want to waste a lot of time guessing, a quality meter allows you to know precisely what you're working with. This one is under $60 from Amazon, it's an investment that will continue to pay off for years to come.


Soldering is one of the single most important parts of building a microphone. Your connections need to be neat and clean because the impedances inside tube condenser microphones are Gig-ohms (that's a lot). You can't measure these resistances with a standard digital meter, also you don't want to overheat fragile precision parts because this can actually change their value.

I like the Weller WES51 adjustable soldering iron/station from Amazon
Do you know how to solder? Do you have a good soldering iron and some very small diameter solder? I've owned a lot of soldering irons over the last 50+ years, the Weller WES51 is a favorite of mine because it's very fast to heat up, it holds temperature well and it lasts a long time, I've never worn one out before it was lost or stolen from a job site.

Besides building microphones you can use a soldering iron to make the best guitar and microphone cables in the world. We will be talking about that in an upcoming Build Your Own Cables article.


Can you strip wire? 

Klein Tools 11057 Wire Stripper and Cutter for 20-30 AWG Solid Wire and 22-32 AWG Stranded Wire

The typical wire gauges used inside microphones are very small so you'll need wire-strippers that work accurately at small gauges. Klein brand tools cost more than the cheapest available but they last forever and do a great job stripping the wire without removing metal.


While we're talking about wire strippers the best wire to use inside a microphone is teflon-jacketed, silver-plated copper. When you get a solder connection too hot Teflon jacket does not melt, unlike PVC jacketed wire which melts quite easily.


Klein Tools D335-51/2C 5-Inch Long Needle-Nose Pliers-Extra Slim

When assembling a microphone there are many circumstances where you'll appreciate having a very high quality set of slender needle-nose pliers like the Klein D335-51/2C. Tasks like bending small wires to fit in tight places are greatly enhanced by having a quality tool. I have some Klein tools that I've been using for well over 20 years. They're not the cheapest but they don't bend and fall apart like some of the lower priced models I've used.

You'll appreciate having a nice complete set of Jewelery screwdrivers too. Microphone bodies and circuit boards typically use tiny metric screws, you'll want screwdrivers that don't strip easily. Be sure the tips of the screwdrivers fully engage the screws you're working with or the heads of the screws will become stripped.
Helping Hands soldering aid

When soldering circuit boards you're going to need something to hold them, I've been using Helping Hands soldering aids since the 1970's. The Deluxe Helping hands pictured above has a magnifying glass and a small moveable light. The light can be very helpful when you're working on very small solder connections or if the light in your work space is not ideal. 

It is vitally important in building microphones that the connections are done neatly and then all solder flux is completely removed using alcohol or flux removing chemical. Failure to follow this simple rule will lead to lots of buzz and head scratching about why the buzz is happening. In most cases buzz and noise can be traced to contamination at the critical high impedance solder connections. 

Are you patient, careful and organized? Good with assembling small things?

These are some of the characteristics you'll need to be successful building microphones. 


I can't recommend highly enough. If you want to build a microphone and have the best chance of it sounding fantastic then start with one of the mic-parts microphone kits. These come with everything you need to build a microphone that competes with anything out there sonically. 

The mic-parts kits utilize custom no name Chinese microphone metal work, the superior sounding mic-parts capsules which are also from China, along with American made circuit boards and the finest circuitry components. Mic-parts tops their microphones off with custom grilles that don't impair the sonics of the excellent sounding capsules. They offer both of the most popular capsule designs (edge and center terminated) in different models for different applications. 

You may already own a microphone that can be modded for superior performance. I've modded several MXL microphones according to the detailed information provided on the web site. Check there to see if you own a model that qualifies for one of their upgrade paths. 


Once you move to microphones priced over $2000 the differences become much more about brand name, reputation and build quality than about sounding better. The quality of the Chinese microphone bodies are a step down from the quality you'd find in a German microphone but it's more than adequate for regular recording studio use as a tool. 

I appreciate premium European metalwork but I'm not willing to pay $1000 for an empty Flea microphone body to house one of my mic creations. My complete V-Twin microphone build was under $650 including shipping. It is not as cool looking as a Flea-47 but in use the performance of the mic has been excellent.

I would not approach building your own microphone with the goal of building a U-47 clone, you'll be disappointed if you compare it to a nice functioning U-47 side by side. Instead, approach building your own as a pioneer on a quest for something great. 

Instead of trying to build a clone of a classic, try building a new classic of your own. You can use similar components to what the original designs used and embellish it with your own personal flair.

Good luck with building microphones, good music to all! currently has a big mic shootout going on where you can listen to and compare 50 microphones, from under $100 to $9000. This is a good way to wrap your ears around these for points of reference. Here is a link to the Sweetwater mic shootout.

Good music to all!


Beez Neez microphones and microphone parts, boutique high quality components, made in Australia

Theirsch microphone products in Germany, premium M7 style capsules

Tim Campbell C-12 capsule replicas from Denmark, premium boutique hand made parts

Apex 460 microphone, the low cost king for rework, modding and experimenting***

The Alctron HST-11A, the Chinese manufacturers catalogue version the Apex 460 is based off of***

Badaax T-11A, currently one of the least expensive versions of the HST-11A, available here on Amazon, an ideal low cost Chinese microphone for modding and experimenting.

Recording Hacks Microphone Database, a great place to learn about microphones from many manufacturers. a great source for quality microphone components, kits and fully assembled boutique microphones. They also offer mod kits and upgrades for a variety of microphones. 12-251 tube mic kit.

***Recording Hacks Microphone Database