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.