Electret mic preamp
About the Electret mic preamp PCB
Electret mic preamp is an open source PCB design by epchain, published on GitHub under the Unlicense license. It is a 2-layer board measuring 25.4 × 12.6 mm, with 8 components from 7 distinct parts.
By type, the board carries 4 resistors, 2 transistors, 1 connector and 1 capacitor.
From the project
Kicad EDA project of a small electret microphone preamplifier
This is a Kicad EDA project of electret microphone preamplifier for improving low-end electret microphone sound on a PC sound card.
Original schematic of preamplifier was found in this article and slightly modified. It uses general purpose PNP transistor instead of germanium transistor. Also, PCB has footprint for small TRS connector.
This preamplifier has it's pros and cons:
Electret mic preamp bill of materials (BOM)
8 components, 7 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | BC847 | SOT-23_Handsoldering | Q1 |
| 1 | BC857 | SOT-23_Handsoldering | Q2 |
| 1 | PJ-306M-2 | Jack_3.5mm_PJ-306-2_Horizontal | J1 |
| 1 | 100uF | C_1206_3216Metric_Pad1.42x1.75mm_HandSolder | C1 |
| 1 | 33K | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R1 |
| 2 | 1K | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R2, R4 |
| 1 | 2K | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R3 |
Electret mic preamp design files
The KiCad project lives in the epchain/electret-mic-preamp repository on GitHub; these links point at the commit this page was built from.
Electret mic preamp: common questions
How big is the Electret mic preamp PCB?
The Electret mic preamp measures 25.4 × 12.6 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Electret mic preamp?
8 components, from 7 distinct parts. The full bill of materials is listed on this page.
Where can I download the Electret mic preamp design files?
From the epchain/electret-mic-preamp repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the Electret mic preamp design in my own project?
Yes, under the terms of its Unlicense license, which epchain chose for the repository.