2 layers114.3 × 104.1 mm
4 layers160 × 100 mm
Preamp 1
bengineer91/Preamp5USB and Analog Input preamp with digital volume control and DSP
- Size
- 160 × 100 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 362
- Nets
- 267
- Pads
- 1,171
- Tracks, vias
- 1,838, 469
- Pours
- 66
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 15 Nov 2025
- Updated
- 18 Sep 2026
Overview
Preamp 1 is an open-source printed circuit board by bengineer91, from the bengineer91/Preamp repository on GitHub. It is a 4-layer board of 160 × 100 mm with 362 parts on 267 nets, routed with 1,838 tracks and 469 vias.
It is built around the OPA1678ID, 24AA256-I/SN and RK09L1120036. Its parts include 138 capacitors, 135 resistors, 15 connectors, 13 diodes and 12 ICs. It belongs with the audio and music boards of this library.
Main components
3
OPA1678ID
SOIC-8-150mil-18V~-2.25V、2.25V~18V -40℃~+85℃ 10pA 10pA 110dB 16MHz 2 2mA 2uV/℃ 4.5V~36V 4.5nV/√Hz@1kHz 500uV 50mA 9V/us Built-in compensation、ESD protection Rail-to-rail output SOIC-8-150mil Operational Amplifier ROHSTexas InstrumentsAudio Amplifiers24AA256-I/SN
SOIC-8-40℃~+85℃ 1,000,000 cycles 1.7V~5.5V 200 Years 256Kbit 400kHz 5ms Hardware write protection function、Noise suppression function I2C SOIC-8 EEPROM ROHSMicrochip TechnologyEEPROM
RK09L1120036
插件-3P,11.4x10.7mm10V 10kΩ 50mW ±20% 插件-3P,11.4x10.7mm Potentiometers, Variable Resistors ROHSALPSALPINEPotentiometers & Variable Resistors
README
README.mdPreamp
** Note ** This got to the ready-to-buy-boards stage when I archived it for more interesting things.
Headphone amplifier with the following features:
- USBC Power Input
- 5V, 3.3V, 3.3VA, and 1.8V LDOs
- +/-12V split rail switching converter, feeding +/-10V and +/-5V LDOs
- ESP32 Module for control and driving a spectrum visualizer OLED display
- York Pico USB to I2S module
- ADAU1701 DSP
- PCM5102A Digital to Analog Converter
- PGA2311 digital volume controller
To Do:
[x] Update Block Diagram with power architecture changes
Layout:
[x] Verify component placement
[x] Routing!
Schematic:
[x] Clean up placement
[x] Part selection for capacitors, verify voltages on schematic
[x] Reduce footprint sizes where possible, mainly capacitors
[x] Pick proper connectors for the front panel stuff
[ ] Decide on header stack height for the York and ESP32
ESP32 Code
[x] Port over spectrum visualizer
[ ] PGA control
CAD
[x] Import board step file
[x] Figure out rear mounting
[ ] Layout front/rear panels
Parts
362| Qty | Value | Footprint | References |
|---|---|---|---|
| 40 | 0.1u | Capacitor_SMD:C_0603_1608Metric | C22, C104, C108, C109, C115, C116, C117, C121, C122, C123, C125, C126, C129, C130, C132, C133 +24 |
| 40 | 10u | Capacitor_SMD:C_0805_2012Metric | C3, C13, C14, C15, C16, C17, C18, C28, C30, C31, C100, C101, C102, C103, C111, C112 +24 |
| 30 | 10k | Resistor_SMD:R_0603_1608Metric | R5, R10, R11, R24, R25, R26, R46, R47, R48, R52, R100, R101, R104, R105, R108, R119 +14 |
| 20 | 0 | Resistor_SMD:R_0603_1608Metric | R12, R16, R17, R39, R50, R53, R54, R55, R56, R57, R58, R62, R66, R67, R71, R107 +4 |
| 12 | 1k | Resistor_SMD:R_0603_1608Metric | R91, R110, R111, R112, R113, R117, R125, R126, R127, R128, R131, R132 |
| 12 | 5020 | 1_User_Library:KEYSTONE_5020 | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12 |
| 11 | 10n | Capacitor_SMD:C_0603_1608Metric | C10, C11, C12, C21, C34, C79, C92, C93, C97, C113, C114 |
| 11 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1, D2, D3, D4, D5, D6, D9, D10, D11, D12, D13 |
| 8 | 100k | Resistor_SMD:R_0603_1608Metric | R31, R35, R36, R37, R90, R116, R134, R135 |
| 7 | 47u | 1_User_Library:CAP_UCD_5X5P8_NCH | C39, C95, C96, C119, C120, C135, C136 |
| 6 | 1.2n | Capacitor_SMD:C_0603_1608Metric | C106, C107, C110, C124, C127, C128 |
| 6 | 1.8k | Resistor_SMD:R_0603_1608Metric | R94, R95, R96, R120, R121, R122 |
| 6 | 270 | 1_User_Library:R_0805_2012Metric_HandSolder | R1, R2, R18, R27, R77, R78 |
| 6 | 820 | 1_User_Library:R_0805_2012Metric_HandSolder | R83, R84, R99, R102, R103, R106 |
| 5 | 100 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R49, R109, R114, R130, R133 |
| 5 | 22u | Capacitor_SMD:C_1210_3225Metric | C1, C2, C6, C46, C54 |
| 4 | 0.22u | Capacitor_SMD:C_1206_3216Metric | C56, C58, C105, C131 |
| 4 | 100p | Capacitor_SMD:C_0603_1608Metric | C118, C134, C137, C138 |
| 4 | 1M | Resistor_SMD:R_0603_1608Metric | R14, R15, R29, R32 |
| 4 | 1u | 1_User_Library:C_0805_2012Metric_HandSolder | C25, C26, C66, C67 |
| 4 | Conn_02x01 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J3, J6, J8, J12 |
| 4 | MountingHole | MountingHole:MountingHole_3.2mm_M3_Pad_Via | H1, H2, H3, H4 |
| 4 | OPA1678 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U11, U13, U20, U21 |
| 4 | RK09L1120036 | 1_User_Library:RK09L1120036 | RV1, RV4, RV5, RV6 |
| 3 | 100 | 1_User_Library:R_0805_2012Metric_HandSolder | R8, R9, R34 |
| 3 | 18k | Resistor_SMD:R_0603_1608Metric | R40, R45, R51 |
| 3 | 4.7u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C20, C24, C27 |
| 3 | 470 | Resistor_SMD:R_0603_1608Metric | R38, R79, R80 |
| 3 | Conn_02x01 | Connector_PinHeader_1.27mm:PinHeader_1x02_P1.27mm_Vertical | J1, J11, J13 |
| 3 | TPS7B8601B | Package_SO:TI_SO-PowerPAD-8 | U2, U3, U4 |
| 2 | 10 | Resistor_SMD:R_1206_3216Metric | R115, R129 |
| 2 | 10k | Potentiometer_SMD:Potentiometer_Bourns_3314G_Vertical | RV2, RV3 |
| 2 | 2.2k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R60, R61 |
| 2 | 2.2n | Capacitor_SMD:C_0603_1608Metric | C89, C90 |
| 2 | 2.2u | Capacitor_SMD:C_0603_1608Metric | C80, C85 |
| 2 | 24p | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C53, C55 |
| 2 | 2k | Resistor_SMD:R_0603_1608Metric | R123, R124 |
| 2 | 4.7u | Inductor_SMD:L_Wuerth_MAPI-4020 | L2, L3 |
| 2 | 5.1K | Resistor_SMD:R_0603_1608Metric | R22, R23 |
| 2 | 56k | Resistor_SMD:R_0603_1608Metric | R42, R44 |
| 2 | 68u | Capacitor_Tantalum_SMD:CP_EIA-6032-28_Kemet-C | C19, C23 |
| 2 | 820 | Resistor_SMD:R_0603_1608Metric | R41, R43 |
| 2 | Conn_01x06 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J2, J10 |
| 2 | Conn_02x03_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J14, J16 |
| 2 | QWIC | Connector_JST:JST_SH_BM04B-SRSS-TB_1x04-1MP_P1.00mm_Vertical | J5, J7 |
| 2 | SPDT_Switch | 1_User_Library:100AWSP1T2B4M7RE | SW1, SW3 |
| 2 | TPS7A39 | Package_SON:Texas_S-PVSON-N10 | U17, U19 |
| 2 | ~ | Diode_SMD:D_SOD-123 | D7, D8 |
| 1 | 100 | Resistor_SMD:R_0603_1608Metric | R28 |
| 1 | 110k | Resistor_SMD:R_0603_1608Metric | R30 |
| 1 | 12.288M | Crystal:Crystal_SMD_Abracon_ABM3-2Pin_5.0x3.2mm | Y1 |
| 1 | 150k | Resistor_SMD:R_0603_1608Metric | R21 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R13 |
| 1 | 1u | Inductor_SMD:L_Wuerth_MAPI-2512 | L1 |
| 1 | 2.2k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R33 |
| 1 | 220n | Capacitor_SMD:C_0603_1608Metric | C37 |
| 1 | 245k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R19 |
| 1 | 245k | Resistor_SMD:R_0603_1608Metric | R20 |
| 1 | 24AA256-I/SN | 1_User_Library:SOIC8-N_MC_MCH | U12 |
| 1 | 27k | Resistor_SMD:R_0603_1608Metric | R118 |
| 1 | 3.3k | Resistor_SMD:R_0603_1608Metric | R70 |
| 1 | 3.3k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R68 |
| 1 | 3.3n | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C41 |
| 1 | 300k | Resistor_SMD:R_0603_1608Metric | R4 |
| 1 | 32.4K | Resistor_SMD:R_0603_1608Metric | R81 |
| 1 | 4.7n | Capacitor_SMD:C_0603_1608Metric | C36 |
| 1 | 42.2k | Resistor_SMD:R_0603_1608Metric | R82 |
| 1 | 51k | Resistor_SMD:R_0603_1608Metric | R3 |
| 1 | 56n | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C40 |
| 1 | 6.8k | Resistor_SMD:R_0603_1608Metric | R69 |
| 1 | 6.8p | Capacitor_SMD:C_0603_1608Metric | C33 |
| 1 | 7.5p | Capacitor_SMD:C_0603_1608Metric | C38 |
| 1 | 75k | Resistor_SMD:R_0603_1608Metric | R97 |
| 1 | 7695 | 1_User_Library:KEYSTONE_7695 | MTG1 |
| 1 | 84.5k | Resistor_SMD:R_0603_1608Metric | R98 |
| 1 | ADAU1701 | Package_QFP:LQFP-48_7x7mm_P0.5mm | U10 |
| 1 | ADM811 | Package_TO_SOT_SMD:SOT-143 | U9 |
| 1 | Adafruit_Feather_Generic | 1_User_Library:Adafruit_Feather2 | A1 |
| 1 | Conn_01x04 | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J9 |
| 1 | Conn_02x02_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x02_P2.54mm_Vertical | J15 |
The 343 most common of 362 parts.
Questions
How big is the Preamp 1 PCB?
It measures 160 × 100 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Preamp 1 use?
362 parts, built around the OPA1678ID, 24AA256-I/SN and RK09L1120036. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Preamp 1 KiCad files?
From the bengineer91/Preamp repository on GitHub, at the commit this page was made from: the board is kicad/Preamp_1.kicad_pcb and its schematic kicad/DSP.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Preamp 1 design in my own project?
Its repository states no licence, so its author keeps all rights: ask bengineer91 before reusing the design.
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