CAD GXL2400 Mods


We offer several modification options for the CAD GXL2400:

  1. Capsule replacement
  2. Grille upgrade
  3. Circuit upgrade
  4. Full PCB replacement

Choose based on budget and skill level. Both circuit upgrade kits will deliver a high sensitivity, low noise microphone. The PCB kit has an onboard switch that can be built as either a Cardioid/Omni pattern switch, or as a -10dB pad. The "pushbutton filter" circuit mod retains the mic's existing HPF switch.

One caution: the "pushbutton filter" circuit mod requires desoldering approximately 20 components, and as such introduces the risk of lifting pads and breaking traces. This mod is not recommended for novices.

Ironically, the PCB kit isn't a great choice for novices either, as it might require minor fabrication work (such as bending frame rails, and sanding off the corners of the PCB) to make it fit the small GXL2400 body.

#1: Capsule Replacement

RK-47 capsule

The GXL2400, like several lookalike microphones from other manufacturers, has a "linear" circuit that is better suited to a K47 type capsule than to the K67 type that it comes with. If your mic seems peaky and harsh, it is due to the mismatch between the K67 capsule (which demands in-circuit high-frequency de-emphasis) and the linear circuit (which provides no de-emphasis).

The easy fix to swap the stock capsule for an RK-47, which would give you a neutral top end, great midrange detail, and a much more balanced sound.

If you choose to install either of the two circuit mod kits below, you could opt for a more brightly voiced capsule like our RK-12 or RK-47, to achieve alternative sonic colors.

#2: Grille upgrade

New grille for GXL2200

Our GXL2200 replacement grille gives your mic a sharp new look.

We made these C12-style grilles for the Apex 460 tube mic platform, but found that they fit the GXL2200 beautifully. The larger interior headbasket volume and more-open mesh seem to give the mic a more open sound.

#3: "Pushbutton Filter" circuit upgrade kit for CAD GXL2400

CAD GXL2400 circuit upgrade kit

Our circuit upgrade kit for the Apex 435 replaces 100% of the mic's audio circuit, and upgrades the DC oscillator circuit too. The modded mic has higher sensitivity, lower noise, lower distortion, and a more pristine signal path. The switchable high-pass filter is retained and improved.

Click for more information on our "Pushbutton Filter" Upgrade Kit for Apex 435.

#4: MP-V57 PCB Kit

Our universal transformerless circuit, the MP-V57 kit, can be shoehorned into the GXL2400. This might require slightly bending the chassis rails outward so that the PCB mounting tabs line up with the mounting holes in the new circuit boards.

This kit provides a completely optimized DC circuit, and pristine audio circuit, with component quality on a par with what you'd see in a $1000 microphone.

The MP-V57 PCB kit has an internal switch that can be built either as a -10dB pad, or (assuming you install one of our large-diaphragm capsules) as a Cardioid/Omni pattern switch.

Click for more information on our MP-V57 PCB kit.