Aztec • Boutique Tube Microphone

$ 2,999.00 (MSRP $ 3,299.00)

The Roswell Aztec is a boutique multipattern tube microphone built without compromise.

The Aztec results from several years' worth of R&D and component testing, during which every piece of the microphone and power supply was reviewed, revised, and improved. The result is a stunning microphone: intimate and rich, never harsh or brittle.



I’m a microphone maniac. Most clones don’t do anything for me.
The Roswell Aztec made my jaw drop. It has this modern pop-edge that differentiates an Elam 251 from a C12, without the annoying harshness of most modern microphones that strive to achieve this.

Christian Seitz
Producer (58M records sold)

It's not a clone... it's better

The Aztec does not pretend to be a copy of anyone else's microphone. We borrow liberally from proven designs, and we relentlessly upgrade everything we possibly can.

The Aztec uses a single triode circuit topology, with a selected 6072 tube. Noise filtering components within the mic are upgraded, using higher quality and higher value parts to reduce noise. Input and output capacitors, which pass the mic's audio signal, are ultra-premium parts selected by ear.

The original European power supplies were typically unregulated, which means tube voltage will drift as the mains AC voltage changes. Rather than subject your recordings to unexpected sonic changes just because the HVAC or refrigerator cycles on or off, we provide a fully regulated power supply that delivers precisely the correct filament and plate voltages, regardless of mains AC changes.

Review Excerpt

I tried Aztec alongside some mics that I had on hand ranging from $5000–$7000, and it absolutely held its own in sonics and depth -- and I do not say that lightly.

Paul Vnuk
Editor, Recording Magazine (see full review here)

Versatility, by design

The Aztec provides nine discrete polar patterns, each of which can be precisely recalled via the rotary potentiometer on the power supply.

A switch on the microphone engages a 10dB attenuation control, which allows the mic to be used for louder sources without internal clipping.

A second switch on the mic engages a high-pass filter, which rolls off the mic's low frequencies (-3dB @ 140 Hz); use this to control proximity effect with close mic placements.


This mic could pass for a $5000 model ... the attention to ALL the details is astounding.

Rob Tavaglione
Writer, MIX Magazine
Catalyst Recording


  • Roswell Aztec microphone
  • Roswell Aztec power supply
  • Gotham GAC7/Neutrik cable
  • AudioQuest IEC power cord (available for IEC type B, E, and G plugs for US/CA/JP, UK, and much of the EU)
  • Shockmount
  • Flight case


Cosmetic Options

The Aztec microphone has a satin black body, or in a color we call "Vintage Cream." The VC mic bodies tend to have minor imperfections, such as a dot or a bump in the finish. The grille is chrome.

The power supply for black microphones is silver. For cream-colored microphones, the power supply matches the microphone color.


Features & Benefits

  • Our RK-251 capsule, single-triode circuit, and custom European-made transformer capture a timeless sound: full low end, honest midrange, and airy, intimate highs.
  • Independent pad and filter switches, and polar pattern control provide comprehensive versatility.
  • The 9-position pattern control, located on the power supply, provides repeatable, discrete selection of polar pattern.
  • Both the Aztec microphone and its power supply incorporate premium, rare, and "unobtanium" components. These parts elevate the mic's sound, drawing comparisons to well-preserved, revered vintage microphones.
  • The included Gotham GAC7/Neutrik XLR cable ensures maximum signal fidelity and minimum voltage loss. The included AudioQuest IEC power cord ensures a robust connection to mains AC supplies.
  • The Aztec power supply is fully regulated, ensuring consistent sound even when subjected to varying AC supply levels.

The two cosmetic options are selectable via the drop-down menu above. The Cream option's availability is limited.

By special request, we can change the rolloff frequency of the high-pass filter, or the amount of attenuation provided by the pad switch. Contact us via email to discuss options.

Jargon for mic nerds

  • The pattern control is a Swiss-made precision potentiometer, which we hand-wire (point to point) using 1% tolerance, audio-grade resistors.
  • The input capacitor was developed decades ago for the aerospace industry; it is a high-voltage part designed to be extraordinarily stable and reliable even when subjected to extreme temperatures and forces (and as such is arguably over-spec'd for use in a microphone -- although we love it for its transparent sound).
  • The Aztec power supply is fully regulated, both plate and filament, to ensure rock-solid power rails for the tube, capsule, and circuitry. Each one is manually adjusted at our shop to 0.1VDC tolerance.
  • The B+ supply runs at a higher voltage than standard; we have optimized the circuit for this.
  • The included XLR7 cable uses genuine Gotham GAC7 and Neutrik connectors. We hand-terminate these in-house, then "burn in" each cable on a proprietary conditioning rig for 72 hours. The heavier conductors in the GAC7 are used for the tube heater circuit, to minimize cable losses.
  • The lid of the power supply is vented to reduce component heat exposure. Power resistors are over-spec'd to ensure long life. Regulators have oversized heat sinks. The circuit board is vented to enable convection cooling of any component that consumes more than 0.1W.
  • All electrolytic capacitors (microphone and PSU) are selected audio grade parts. Most are our own proprietary recipe, Roswell branded parts.
  • Internal wiring in the PSU is Kimber brand OFC, solid core, with Teflon insulation; it's difficult to use, but is the best-sounding wire we've ever tested.

See the PSU internals below. This image shows some of our custom electrolytic filter capacitors, vintage Japanese audiophile resistors, bridge rectifier boards (mounted vertically to aid in convection cooling) with NOS Telefunken diodes, gold-plated German-made fuse and socket, oversized heat sinks on the regulators, etc.

Related Products