T-47 DIY Condenser Microphone Kit – Microphone-Parts.com
Channel: Audio Builders Workshop
Date: 2017-08-29

Audio Builders Workshop will be unboxing kits and DIY audio parts, and tools from Collective Cases, DIY.RE, Microphone-Part, JLM Audio, Hairball, Expat Audio, Bumblebee DIY Pro Audio, Austin Microphones, Audibility Recording, GKL gKit Baby / ORA, Vintage Microphone PCB Kit, Sparkos Lab, Geistnote and many more!

About the Circuit

We started with one of the simplest and cleanest vintage mic circuits in history, Neumann's KM84. You don't need 500 components to make a great microphone; we'd agree with Neumann engineers that the simplest solution is often the best.

We implemented the circuit without electrolytic or tantalum capacitors. We picked a vintage JFET, which we put through a rigorous selection and biasing procedure (see below). We removed the silly attenuator components that needlessly reduce output level. We found a wonderfully warm, US-made output capacitor. And a shockingly good transformer...

About the Transformer

In a circuit with such a simple audio path -- capsule, JFET, capacitor, transformer, in that order -- every one of those components is critical. We knew the transformer would have to be something special, so we tested six of them, including models from the biggest names in audio transformers.

The best performer of the bunch was our own US-made, custom-wound 6.5:1 unit, which delivered the best combination of measured performance (read: harmonic distortion) and sound