![Custom Microphone Transformers: 12dB Lower Noise Floor](["https://zxycoil.oss-cn-beijing.aliyuncs.com/upload/products/zxy-g14-1-1-microphone-transformer-with-permalloy-core-1.jpg"])
Background
A professional microphone brand needed a lower noise floor and smoother high-frequency response for its new large-diaphragm condenser microphone. The previous transformer rolled off above 10kHz.
Challenges
- Response deviation within ±0.5dB from 20Hz to 20kHz.
- Transformer noise below the microphone self-noise.
- Fit inside a 46mm diameter body.
- Flexible small-batch production across models.
Our Solution
We used a 1:1 permalloy toroidal core with interleaved sectional winding and an electrostatic shield.
- Interleaved primary/secondary winding cut leakage inductance by about 40%, extending the roll-off point beyond 40kHz.
- Copper foil electrostatic shield with separate lead suppresses common-mode interference.
- Annealed and aged core reduces magnetostriction noise; epoxy potting adds moisture and shock resistance.
Results
- Measured response deviation ±0.4dB from 20Hz to 20kHz.
- Equivalent input noise reduced by about 12dB.
- First 2,000 pcs passed acceptance in one run and moved to regular supply.