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Apex 460 Mod Kit

Item #F460
In Stock
Pre-order for June 5 shipping!!
The Apex 460 is the best tube mic mod platform on the market. This kit replaces 100% of the audio signal path with handpicked, no-compromise parts.

Product Features

•Audio circuit mod designed by Fox Audio Research
•Custom circuit boards and transformer
•Includes selected, low noise Russian tube
•Includes selected high-end capacitors
•Includes full-color installation manual
•Choose from four large-diaphragm capsules

Introducing the new Fox 460 Mod Kit

Our new “Fox 460″ mod kit for the Apex 460 tube microphone provides a massive upgrade in the sound quality of the mic. We’ve removed every compromise by replacing 100% of the signal path:

  • New capsule
  • New circuit (and new circuit boards)
  • New transformer

Choose Your Color

Choose from three core sonic palettes by selecting a capsule:

  • U47 → RK-47 or RK7 capsule
  • C12 / ElaM 251 → RK-12 capsule
  • U67 → RK-87 capsule

The Fox 460 is not a clone of any of these vintage microphones, but we can certainly achieve a similar tone and frequency response… for a tiny fraction of the price.

Then fine-tune the mic’s high-frequency response using the instructions in the kit to establish exactly the voicing you desire.

About the Apex 460

The Apex 460 (aka Alctron T-11, aka Alctron HST-11A) is probably the most modified mic in the world. It is an affordable, solidly built tube mic. But its capsule is too peaky and bright, its circuit is too distorted, and its transformer varies wildly in performance from one mic to the next.

Upgrading the Apex 460

The core circuit in our Fox 460 mod was designed by Brian Fox of Fox Audio Research. Brian spent weeks reverse-engineering this microphone and testing numerous iterations of component changes. After countless electronic and acoustic tests, he settled on the recipe for our Fox 460 mod kit.

Then we took it a giant step forward by finding the best parts we could for every component on the board, and designing DIY-friendly custom circuit boards to accommodate those parts.

And then we took it another giant step forward by sourcing a custom-wound output transformer that gives us lower distortion and tighter bass response.

And then we took it another step forward by fully analysing the effect of the “tone” capacitor option, and providing clear documentation for the amount of rolloff created by a variety of cap values. This allows the circuit to be fine-tuned to suit every desired voicing.

Mod Kit Benefits

As compared to the stock microphone, this circuit offers:

  • Increased headroom
  • Superior power filtering
  • Lower self-noise
  • Reduced distortion
  • Reduced transformer ringing
  • Less congested sound
  • Higher output

What’s in the kit?

We give you everything you’ll need to transformer your Apex 460 (or compatible mic) into a studio powerhouse:

  • Custom circuit boards. We designed these in house and manufacture them in the US. We use high quality two-layer boards with clear silkscreen markings and reasonably sized solder pads.
  • Fantastic components. The kit includes 100% of components needed to build the mic circuit. All these parts are selected from among the best available, including low-noise Dale metal film resistors, a styrene input cap from Reliable, high-grade electrolytics from Panasonic and Elna, a NOS styrene tone capacitor, an excellent US-made output capacitor, Wima film capacitors, and a US-made output transformer that was custom wound for this specific circuit.
  • Low-noise tube. The tube is a 6072a type, manufactured in Russia, then tested and selected in the US to conform to our specifications for noise and microphonics. We picked this 6072 over many other types because it has better distortion characteristics.
  • New capsule. The capsule is the most important component of the entire microphone. This kit includes your choice of sonic colors: our famous RK-47, RK-12, RK-87, or RK7.
  • Internal wiring. We’ve sourced pre-cut and tinned, color-coded, multistrand silver-plated OFC with Teflon insulation, made in the US specifically for this kit. One exception to this: the main input wire that carries the high-impedance audio signal from the capsule to the tube is solid-core, 100% silver Kimber Kable.
  • Unparalleled documentation. Each kit comes with a full color, step-by-step instruction manual. Our installation guides are known throughout the DIY audio community, and have been widely praised as the best available.

  • Apex 460 Capsule Replacement

    The stock 32mm K67-style capsule in the Apex 460 is part of the problem with the stock microphone. Even if your mic’s capsule is a good one — with two intact diaphragms, no wrinkles or dings — it produces a rising high-frequency response that you usually don’t want to hear.

    Our version of the AKG CK12 is the most popular choice for the 460 mod, due to AKG’s use of the CK12 in the famous C12 and ElaM 251 mics (after which the 460 is, to some extent, modeled). Our RK-12 has a broad, musical presence boost that is great for bringing out detail in intimate vocals, drum overheads, and location recordings.

    Our RK-47 is a modern version of Neumann’s famous K47 design. This is the most balanced-sounding capsule we make, and it works wonderfully for capturing acoustic instruments and vocals with warmth and articulation. If most of your inexpensive condensers sound too bright, you’ll love the RK-47.

    A variation of the RK-47, our RK7 is the darkest, most colored capsule we make. It reaches lower than the RK-47, and rolls off the highs sooner, giving it a characteristic vintage sound. The RK7 is great for room mics, for taming sibilant voices, and for thickening the sound of acoustic instruments.

    The RK-87 is our version of Neumann’s K67/K87, the capsule in the U67 and U87. We build it with a milder high-frequency peak than the original, as this tends to work better with most microphone circuits. If you’re choosing this capsule for your Fox 460 build, plan to build some high-frequency rolloff into the circuit to approximate the K67 sound.

    Compatibility Check

    Our mod kit is designed as a drop-in replacement for the circuit in the Apex 460, Nady TCM1150, Carvin CTM100, and Alctron T-11A (aka HST-11A). We believe it will also fit the BadAax T11-A, which we’re told is an Alctron T11-A, although we have not personally verified this.

    It should also work in any donor body that will physically accommodate its circuit boards and a 6072A tube and transformer. Practically speaking this means it will fit the 46mm diameter tube mics with switches such as the TnC ACM-1200, Avantone CV12, A.I.R Liberator, although you would have to remove the switches. We choose to use a higher-quality output cap rather than leave room for the switch PCB.


    The first two production run of these kits sold out immediately. The third production run will begin shipping on June 5.