C12/251 Tube Mic Build for Client
I recently received a phone call from Cardiff. Huw had seen my blog post on modifying an Alctron MC001 microphone and wanted me to build him some mics. He was after a couple of valve/tube microphones based on the AKG C12/Telefunken ELA m251. “Sure,” I said, “Why not?”
The Mic Kits
First Things First
The first thing I did was to change the power supply unit. To do this you swap out a couple of low-quality diodes – simple enough. This also comes set for 120V mains current and needs changing.
– see pictures below:
Sockets & Transformer
Wiring up comes next and this is awkward. Mic parts provide several short wires as well as some solid silver-core wire. These short wires connect both PCBs together as well as the 9-pin tube socket. Connections are also made from the transformer and XLR socket. These wires make their way up the mic chassis and have retaining clips to secure them away from the tube.