1. The bias voltage board can be applied to other triode front-mounted printed circuit boards, suitable for DIY use by friends with strong manual skills, friends who have no practical ability, please buy our front panel + polarizing plate 2.60V single output, +-60V dual output, +60V dual input, +60V and +120V dual output, can be selected according to the bias voltage of the large diaphragm, single output is suitable for single-layer, double-diaphragm microphones Output, suitable for dual-diaphragm microphone head 3. It is recommended to use +60V and +120V dual output versions. If you feel that the sound is not strong enough, and the sensitivity is not high enough under 60V voltage, you can switch 120, and then you can connect a switch parameter: Product name: Microphone circuit board Microphone type used: large diaphragm, mid-diaphragm condenser microphone (suitable for diaphragms with a diameter of 25mm or less) Frequency response: 40hz-16khz Sensitivity: -48db Output impedance: 250 ohms Maximum sound pressure level: 125db Signal to noise ratio: 60db Power supply: 15-48V phantom power Working current: 3.1ma Purpose: DIY production repair modified circuit board Colour:Red Material:PCB+metal Size:45x15.8mm Package Contents: 3 x Microphone circuit board