SC440 Preamp
About the SC440 Preamp PCB
SC440 Preamp is an open source PCB design by lk-ek, published on GitHub under the Custom license license. It is a 2-layer board measuring 30 × 35 mm, with 27 components from 18 distinct parts.
Other key parts include the OPA1678IDR. By type, the board carries 10 resistors, 9 capacitors, 5 test points, 2 connectors and 1 IC.
From the project
SC440 OPA1678 microphone preamp
Caveat: measurements show that the theoretical use for this preamp is a reduction of the noise floor by a whopping 0.2dB. The noise seems to come from either the capsule or the analog board.
So this is a nice flex mod as an exercise in analogue circuitry, but don't expect any quality gains from it at all.
A 5 V analog gain board for the t.bone SC 440 USB microphone. It sits between its original microphone/JFET board and USB/ADC board, AC-couples the signal, rebiases it around a buffered half-supply reference, and adds selectable gain. The aim is to use less gain in the following ADC stage.…
Main components on the SC440 Preamp
SC440 Preamp bill of materials (BOM)
27 components, 18 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | OPA1678IDR | SOIC-8_3.9x4.9mm_P1.27mm | U1 |
| 1 | JST-XH 1x04 TO DIGITAL BOARD | JST_XH_B4B-XH-A_1x04_P2.50mm_Vertical | J1 |
| 1 | ANALOG BOARD | PinHeader_1x04_P2.54mm_Vertical | J2 |
| 5 | TestPoint | TestPoint_THTPad_D1.0mm_Drill0.5mm | TP1, TP2, TP3, TP4, TP5 |
| 1 | 2.2u | Faratronic_C241J225_P5.00mm | C1 |
| 1 | 1u | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2 |
| 1 | 47u | CP_Radial_D5.0mm_P2.00mm | C3 |
| 2 | 100n | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4, C8 |
| 2 | 330p | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C5, C9 |
| 1 | 10u | CP_Radial_D5.0mm_P2.00mm | C6 |
| 1 | 1n | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C7 |
| 2 | 0 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2 |
| 1 | 22R | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R3 |
| 2 | 1k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R9 |
| 2 | 10k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R5, R7 |
| 1 | 100k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R6 |
| 1 | 2.2k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8 |
| 1 | 100R | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R10 |
SC440 Preamp design files
The KiCad project lives in the lk-ek/SC440_Preamp repository on GitHub; these links point at the commit this page was built from.
- LayoutSC440_Preamp.kicad_pcb
- SchematicSC440_Preamp.kicad_sch
SC440 Preamp: common questions
How big is the SC440 Preamp PCB?
The SC440 Preamp measures 30 × 35 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the SC440 Preamp?
27 components, from 18 distinct parts. The full bill of materials is listed on this page.
Where can I download the SC440 Preamp design files?
From the lk-ek/SC440_Preamp repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the SC440 Preamp design in my own project?
It is published under Custom license, which limits how it may be reused; read the license before building on it.