T-25 Microphone Kit

The T-25 is a professional quality condenser microphone with a remarkably musical frequency response -- not hyped in the high end like so many inexpensive microphones.

The T-25 is a medium-diaphragm condenser microphone kit that we think sets a new milestone in price/performance ratio. We have adapted our popular T-84 circuit kit to make it easier to build without sacrificing tone. This circuit gives the T-25 microphone a rich texture reminiscent of vintage microphones, but at a tiny fraction of the cost.

Applications

The finished T-25 will find uses throughout your studio, from vocals to drum overheads to guitars. We designed it to mimic the behavior of our T-12 and T-47 microphones, in that it will saturate under moderate SPL in order to capture harmonically rich sound. This circuit has a mild compression effect; it gently attenuates transients, which can make drum tracks easier to mix.

Audio Circuit Details

The T-25 uses our new EXF1 circuit kit. It is a transformer-balanced design based on Neumann's KM84 circuit. It is easy to build, requiring just 14 components (!) plus capsule and transformer.

We implemented the EXF1 with all our favorite high-performance parts, including a NOS JFET that we manually bias using signal injection and a distortion meter. This step ensures that your microphone has the maximum possible headroom.

In the Box

The T-25 kit includes:

• the microphone metalwork (body/chassis/grille), with XLR3 insert pre-installed and wired
  
• the microphone capsule, with custom mounting post
• the EXF1 circuit kit, including our custom transformer
  
• detailed, step-by-step, color illustrated build guide
  
• all the screws and wires needed to build the microphone. Just add solder.
• a swivel mount for connecting the mic to a mic stand.

Cosmetic Options

As of January, 2023, we offer two cosmetic options. Both have a satin black finish. One has a satin nickel plated grille. The other has a tall, C12 style chrome grille.

Both these metalwork options have an embossed MP logo badge.

The taller grille gives the mic a slight extension in the "air" frequencies above 10kHz. (Note - this does not mean the mic is "bright." Brightness is usually defined as a 3-5dB boost in the 8-10kHz range.)

About the Build Process

This is the easiest-to-build full microphone kit that we make. It has half as many components as the S-25, which is the kit that first-time kit builders typically build at our workshops.

Completing the microphone requires soldering 14 components and 9 wires. If you have never soldered before, we recommend practicing on an inexpensive soldering practice kit first.

You will need to supply a soldering iron, ideally one with adjustable temperature so that you can set the temp to 700 degrees F. Colder irons are harder to use.

Please see this listing of recommended DIY audio tools.

We supply full color, step-by-step instructions for the build.

We have a livestreamed demo build of this kit. It's not a tutorial video, but does illustrate the process.

First DIY Mic?

See the list of essential tools.

We recommend this magnifier. Passive components are small; value markings are difficult to read. We can't make the parts bigger, but we can help you see them.

Audio Samples

Charlie Waymire and Ernesto Homeyer of Ultimate Studios, Inc built a T-25 during a live webcast, and later recorded drums (mono, front of kit), acoustic guitar, bass, and electric guitar with a single mic. The video here starts right on the audio samples; rewind it for more info on placement.