Category Archives: Microphone Modifications

Information on modifying a microphone. Sources of parts and kits. How to do modifications.

Groove Tubes GT-55 and Sterling ST-55 Mod Using the Micparts T84-55 Circuit Kit

StudioMicZone

I have always liked the Groove Tubes resonator capsule design since it adds diversity to my mike locker. Over the past couple of years, I have acquired a couple of GT-55s and the successor to it, the Sterling ST-55, as they became available on eBay.

So, when micparts came up with the T84-55 circuit kit, I jumped at the chance to have a microphone with the resonator capsule and upgraded electronics and was near the beginning of the line to get the new kit. I decided to video the modification process in case anyone would like to see what is involved in a mike mod if they are anticipating one or just curious.

Here’s a video of the whole process. Micparts does a superb job on their instruction manuals with step-by-step instructions and color photos. If you have the ability to solder and can follow instructions, the process should yield success.

The micparts T84-55 circuit kit is available on the micparts website.

Condenser Microphone Mods

StudioMicZone

Studio Projects C1 and C3 Microphones with new capsule and mod kit.It’s amazing the number of small manufacturers creating great microphones. It’s good to have a “palette” of different sounding microphones to record with, and the large number of companies building quality microphones and providing modification kits and services makes it easier to build a diverse microphone collection.

I’ve acquired Studio Projects C1 and C3 microphones as these microphones have outstanding electronics. Both the “B” and “C” series Studio Projects microphones use a transformerless circuit based on the Schoeps design. Brent Casey of PMI adapted the design and it is built with quality components. Some find the microphone a little too bright and there are a couple of solutions.

I have upgraded the circuit in the C1 with an upgrade kit from microphone-parts.com.  This mod kit provides an adjustable high-frequency roll-off to tame the brightness of the microphone. If you have never modified a microphone before, this kit is a good place to start because it is very simple, and the C1 and C3 microphones are large and easy to work on.

Another way to reduce the high-end on the mike is to replace the capsule with a darker capsule like the MicParts RK-47. With this capsule, the EQ kit isn’t necessary. I replaced the capsule in the C3 with an RK-47 capsule. I’m looking for another C3 that I will modify with the circuit upgrade kit and install an RK-12, AKG style capsule. I used these mikes on a brass section and they sounded great. I can’t wait to try them out on other sources including vocals.