ADK TC Mod Service

ADK made several mics in its TC series: the TC-251, TC-67, and presumably the TC-47 and TC-49. These were Cardioid-only tube mics that shipped in a giant suitcase with shockmount, power supply, pop filter, and 7-pin cable. We have developed an upgrade service to address a few of what we see as the weak points in what are otherwise nicely designed microphones: The stock 12AX7 tube has very high gain and very high distortion, giving the mics limited headroom for moderate to loud sources. We replace the tube with one that reduces the mic's output level by 6dB (which helps prevent clipping the preamp on moderate-volume sources), and lowers harmonic distortion by up to 20dB. We replace the output capacitor (an electrolytic) with a high-grade film capacitor, which provides cleaner, more cohesive sound. Given that electrolytic capacitors tend to fail more frequently than film capacitors, this upgrade also reduces the likelihood of a future mic failure. We replace the input capacitor, which a