Microphone Modification Kits

High-performance, high-end microphones do not have to cost a fortune. You can build them yourself — start with an inexpensive “donor” microphone, then install our capsules and circuit mod kits. They’re easy to install, and will give you a stunning audio upgrade. These mics are our customers’ secret weapons!

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Available Mod Kits

We have mod kits in stock for the following microphones. Click any mic photo for details.

PCB Kits


MXL 990 PCB Kits

Fits MXL 990, 990XL


MP-V57 PCB kit

Fits MCA SP1, MXL 2006,

V63M, 910, V250 & more

Tube Mic Mods

Apex 460

Apex 460 Mod Kit

Starting at $109

Alctron T-11 / HST-11A

Alctron T-11 (HST-11A) Mod Kit

Starting at $109


Carvin CTM100 Mod Kit

Starting at $109

FET Mic Mods

MXL 990 Mod Kits

Starting at $99


MCA SP-1 Mod Kits

Starting at $99

MXL 2001 Mod Kits

MXL 2001 Mod Kits

Studio Projects C1

Studio Projects C1 Mod Kits

Introductory Price: $49

Studio Projects C1

Studio Projects C3 Mod Kits

Introductory Price: $49



The new “Linear 87″

MXL V63M Mod Kits

Starting at $99

Monoprice 600800

Monoprice 600800 Mod Kit

Starting at $199

MXL 770 Mod Kit

Starting at $199


CAD GXL2200 Mod Kits

Starting at $99

Nady SCM 800

Nady SCM 800 Mod Kits

Starting at $199


MXL 910 Mod Kits

Starting at $129

MP-03 XF

“Linear 87″ Kit

MXL 990S Mod Kit

Starting at $199

MXL 550

MXL 550 Mod Kits

Starting at $129


Apex 435 Mods

(starting at $99)


t.bone SC400 Mods

(starting at $99)

Gauge ECM-87 Stealth

Gauge ECM-87 Mods

(starting at $99)

MXL 2006

MXL 2006 Mod Kits

Starting at $49

MXL V250

MXL V250 Mod Kits

Starting at $149

MXL V67 Mod Kits

MXL V67 / V67G Mod Kits

Order Mod Kits

To order microphone mod kits, click the specific model above.

Microphone Modification Kits

If you search online, you’ll find dozens of recommendations for microphone component upgrades. Such recommendations are well-intentioned, but they don’t offer a complete circuit upgrade plan, nor comprehensive instructions. In contrast, our mod kits were designed by experts, and come with fantastic step-by-step documentation. The goal for these kits was not simply to upgrade a few capacitors, but rather to overhaul the entire circuit of the mic, in order to deliver performance like you’d expect from microphones costing 3-5 times more.

The core circuit upgrade in our FET mod kits was designed by audio circuit guru Jim Williams (of Audio Upgrades). Jim no longer performs commercial mic mods, but we’ve been able to capture the magic of his favorite mods in kit form — and we’ve improved it by enhancing the modification to the mic’s DC power circuitry, and further by supplying a selected, pre-biased JFET. If you can drive a soldering iron, you can turn some popular inexpensive mics into serious pieces of studio gear. Because Mr. Williams performed hundreds of these mods over the years — including a dozen for himself — he had the opportunity to develop, revise, and refine a specific recipe that yields an extraordinary sonic bang for the buck.

Our Apex 460 / Alctron T-11 mod kit was designed by Brian Fox of Fox Audio Research. Brian’s non-nonsense, test-driven approach to circuit optimization yields a fantastic upgrade for this popular tube mic.

Our new “Linear 87″ mic mod was designed by Dr. Mark Fouxman of Samar Audio, and is based on a very special 10:1 output transformer created specifically for this microphone.

We source all the best components, hand-select and match all the paired resistors and capacitors, and package them up with a detailed, model-specific, full-color installation manual. We want to make sure your mic fires up and sounds awesome on the first try.