Mini K47 Condenser Microphone

$ 389.00

  • The original compact K47 condenser microphone
  • Designed, assembled, and tested in California
  • Vintage tone from true 34mm large-diaphragm K47 capsule
  • Handpicked NOS audiophile components
  • In stock for immediate shipment


My latest clean guitar tracks have all been a Princeton with a Mini K47 into an MCI pre. Gold. The Mini K47 should be the next mic in everyone’s locker after a '57.

- Paul Smith, 8 Days A Week Studio


The Mini K47 captures the tone of a vintage microphone, with modern performance specifications.

Like all Roswell microphones, the Mini K47 is designed, assembled, and tested in California.

"K47" refers to the capsule design. Our K47 capsule is modeled after the one in the most famous microphone of all time. It provides a full, balanced tone without any harshness or hype in the upper frequencies. It will record less sibilance and fewer mouth sounds on your next vocal track. It will add weight, body, and tone to high strings and electric guitars. It will reduce the jangle in strummed acoustic tracks.

We created a clean, transparent circuit design. It lets the sound of the capsule pass through without alteration. Self-noise and distortion performance are on par with microphones costing significantly more. The circuit incorporates the best tricks we’ve learned from modifying and upgrading other companies’ products.

Every Roswell microphone is subjected to a 24-hr "burn in" on our conditioning fixture, then tested extensively prior to shipping: polarity, noise, frequency response, sensitivity, and more. We perform an acoustic sweep test and multiple listening tests before any microphone leaves our facility.

The Mini K47 has a durable, heat treated finish. Each mic ships with our exclusive Cutaway™ shockmount, Roswell branded microfleece mic sock, and a flight case.

Recording drum overheads or other stereo applications? Click for matched stereo pairs of the Mini K47.

Click here to customize / personalize your Mini K47 via the Roswell Mic Builder.

Cosmetic Options

The standard production Mini K47 uses a black metallic sparkle finish. We offer a series of limited-availability finishes. Click the link above to see current options.

Circuit Options

The standard Mini K47 circuit is optimized for high dynamic range. It works well on sources from vocals to drum overheads, from piano to loud electric guitar cabinets. This is the best option for most audio engineers. This is the circuit that has earned all the superlative reviews you've seen about this mic.

If you only ever intend to record quiet acoustic sources, such as acoustic guitar, strings, vocals, voiceover, or ensembles, we can replace the standard circuit with a high output, high sensitivity design. These "High Output" microphones will not work well on loud sources such as drum overheads, horns, or amplified instruments. But they will deliver superior results on very quiet sources.

The High Output Mini K47 is built to order; allow 3-4 business days for assembly, testing, and burn-in.

We also offer the option of an internal pad switch. 99+% of users would never need this; the standard mic has sufficient headroom for vocals, guitar cab, and drum overheads. If you expect to record extremely loud sources, contact us to request the inclusion of a non-capacitive pad (which would be accessed via a miniature toggle switch inside the mic).

We have a collection of audio clips below. See also the growing collection of demo videos for the Mini K47.


  • True single-backplate 34mm K47 style capsule
  • Ultra-clean transformerless circuit
  • Imported, NOS, audiophile-grade signal capacitors
  • Heavy, solid steel body with durable finish
  • Exclusive Cutaway™ non-resonant shockmount
  • Natural, unhyped frequency response
  • Enhanced articulation
  • Solid, high-quality construction
  • High sensitivity
  • Low self-noise and very low distortion
  • Modern performance with vintage tone
Component Details

The most unique thing about the Mini K47 is its capsule: a true 34mm (large diaphragm) K47 type capsule, modeled after the capsule in the most famous microphone of all time. We selected this capsule because it delivers a sound that is impossible to achieve with any other capsule design: tight lows, beautiful midrange detail, and a neutral, rather than a hyped, top end.

Mini K47Our component selection process for the Mini K47 benefits from a decade's worth of experience in upgrading audio circuits. The parts in this mic were chosen because they sound good, and they sound good together, and they give the mic the voice we want it to have.

Start with the main transistor, T3 in the photo at right. While most competing models use a generic low-cost part called the 2SK170, we don't, because the 2SK170 has crazy high input capacitance, which creates an unneeded attenuation pad in most of the mic implementations in which it is used. We favor an uncommon vintage transistor with superior performance characteristics. Then we manually "bias" each one in a custom text jig, which ensures that each Mini K47 has high SPL and low distortion.

The input coupling capacitor (not visible here, for reasons that are about to become obvious) is the first component a "modder" would change, because so many condenser mics use a low-grade part in this position. For the Mini K47, instead of upgrading the capacitor, we redesigned the input circuit to eliminate the need for this capacitor entirely. The best-sounding capacitor sounds a lot less good than not having one at all!

An added benefit to our mic's streamlined input circuit: the JFET "gate" (audio input) is held at higher impedance, which helps reduce noise. We form this critical audio input connection "dead bug" style, off of the surface of the PCB. It costs more to build the mic this way, but it sounds better, so that's what we do. These connections are hand-soldered, cleaned, and insulated with a special acrylic coating, to prevent signal degradation over time.

The main signal capacitors are vintage European parts, which we selected by ear after auditioning all the usual suspects and a fair few unusual ones.

The electrolytic capacitors in the center of the PCB were also selected by ear, despite not being in the audio signal path. It is likely that not everyone will hear the difference. Some will, though. Even if you don't, your Mini K47 gets the good parts anyway.

This circuit topology is essentially balanced at the JFET, with two equal output circuits that are mirrored in the PCB design. These two output legs benefit from having matched components. We use 1% tolerance resistors, and we hand-match the signal capacitors to 1% (or usually better).

This combination of components delivers a sonic profile that is much more musical and balanced than anything in its price category.

Model: Mini K47
Acoustic Principle: Pressure gradient transducer
Polar Pattern: Cardioid
Capsule: 34mm O.D. True Condenser, K47 style, single backplate
Frequency Range: 20 - 20,000 Hz
Sensitivity: 14 mV/Pa for Mini K47
Impedance: 112 Ohms
Signal-to-noise: 81 dBA
Equivalent noise: 13 dBA
Supply voltage: 48±4 VDC
Output: Electronically balanced (transformerless)
Physical dimensions: 150 × 44mm; 325g (mic only)
Frequency Response

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