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Apex 460 Mod Kit

Item #Fox 460 / FOX SG
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Watch for our newly revised tube mic mod kit in 2015.
The Apex 460 is the best tube mic mod platform on the market. These two mod kits fix all the problems with the mic, enabling it to perform like the vintage European microphones after which it was modeled.

Product Features

•Audio circuit mod designed by Fox Audio Research
•Includes selected, low noise Russian tube
•Includes selected high-end capacitors
•Includes full-color, 30-page installation manual
•Choose from RK7, RK-47, or RK-12 capsules
•Choose from FOX or FOX SG kits

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 that sounds pretty good in its stock form. And there are a million ideas on the audio forums about how to make it better.

Unfortunately, most of those million ideas are incomplete, and incompatible with one another. Never has a mic needed a comprehensive mod recipe more than the Apex 460!

Upgrading the Apex 460

No mic benefits from a haphazard collection of component upgrades. The capsule, tube, circuit, and transformer all form a system. They have to work together, or the mic won’t sound good.

Therefore, what the Apex 460 needs is a comprehensive overhaul of the circuit. This is where Fox Audio Research comes in. Brian Fox spent weeks reverse-engineering the Apex 460 and testing numerous iterations of component changes. After countless listening tests, he settled on the recipe for our Fox 460 mod kit.


Mod Kit Benefits


This modification makes fundamental changes to the topology of the circuit. It is not simply an in-place upgrade of a few key components.

Rather, the mod changes current flow to the tube to increase headroom, improves power filtering, drops the noise floor, reduces transformer ringing, and cuts distortion at multiple points throughout the circuit.

To be sure, the kit includes upgrades for all the key capacitors as well, resulting in a much more open and uncluttered sound.


What’s in the kit?

We use ultra-low-noise Dale metal-film resistors, because they’re built to very high standards and they sound great in our FET mod kits. We use a NOS polystyrene input coupling cap from TRW. We have a fat polypropylene cap from Panasonic on the output, bypassed with a Wima film cap for high-frequency details. The low-frequency filter cap is an Elna Silmic II. And we’re using Nichicon electrolytics in the power filtering circuit.

If you’re installing our RK-12 capsule, we’ll also include a small polystyrene EQ capacitor. This is an optional installation; it gives you the choice of a Telefunken Ela M 251 response, or an AKG C12 response.

Because polystyrene caps are sensitive to heat, we supply a metal alligator clip for use as a heat sink when you’re soldering the polystyrene caps in place.

The kit includes a selected, low-noise Russian 6072 tube; this is the specific tube that this circuit was optimized for.

We provide step-by-step instructions for the mod in the form of a full-color, 32-page manual. We’ve revised the mod process significantly over the past 6 months, based on regular feedback from customers of our FET mod kits. The result is the best manual we’ve produced to date, and it gets better with every printing.

Each kit also includes your choice of our large-diaphragm replacement capsules:


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.

Because the modified circuit is linear, we won’t offer a K67 replacement option. But all three of the following will work wonderfully with the modified circuit:

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.

A more neutral option is our RK-47, 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 FOX Mod SG edition

SG Mod Kit Enhancement for Apex 460
For those modders who want the very best, we are excited to introduce the SG Edition!

SG stands for Silver and Gold. We’ve taken the FOX mod kit and enhanced it with precious metals:

  • A gold-pin EHX 6072 tube, hand-selected for low noise and low microphonics
  • a length of Kimber Kable Ag25SC “Black Pearl” solid-core silver wire, to replace a critical input wire inside the microphone
  • WBT 4% Silver Solder, the best-sounding solder we’ve found (note: lead-free WBT 4% silver is available for EU customers)

This enhanced kit includes two premium capacitors as well:

  • the input coupling capacitor is upgraded to a polystyrene unit made by Reliable Capacitors specifically for this kit.
  • the EQ capacitor is upgraded to a NOS polystyrene from Mial. (We used to use Siemens, as in the photo above, but the Mial is better.)

If you’re looking to squeeze the highest possible performance out of your Apex 460 mod, the FOX SG is the kit for you! Kimber’s “Black Pearl” wire retails for $27/ft. WBT’s 4% silver solder costs over $1/g. RelCaps have been a top pick by audio enthusiasts for years. We’ve saved you the time and hassle of searching out individual components, and numerous individual shipping charges, to bring a sweet little sonic boost on top of the substantial sonic upgrade of the standard FOX mod kit.

Compatibility Check

Our mod kit is compatible with the Apex 460, Carvin CTM100, and Alctron T-11 (aka HST-11A). It is very likely compatible with the Nady TCM1150 as well; click the image link below to verify.

The kit is not compatible with the TnC ACM-1200, Avantone CV-12 or any other tube mic with switchable pad and filter. We hope to introduce a kit specific to these mics soon. (Drop us an email so we can get a sense of how many people need this.)

The best way to verify compatibility is to expose the circuit boards on your mic (no tools required; just unscrew the large nut at the base of the mic), then compare to the photos here. If your mic’s circuit boards are identical to the Apex 460 PCBs, then this kit will work fine for your mic too.

What about the transformer?

One of the benefits of this kit is that it makes the circuit work well with the stock transformer. You do not need to upgrade the transformer with this modification. And in fact, we don’t recommend it.

If you insist on swapping the transformer too, here are suggestions from Brian Fox:

  • AMI T8 ($120) U47 style, 7:1 ratio, recommended for RK-47 capsule
  • AMI T14 ($95) C12/ElaM 251 style, 12:1 ratio, recommended for RK-12

Please note: Replacing the stock Apex/Alctron transformer for the AMI T14 will drop the mic’s output level by 3dB.

T14 users can also expect to hear slight attenuation in deep bass frequencies, and slightly boosted high frequencies, as compared to the stock transformer.

Contact an AMI dealer here for more information on availability, pricing, etc.