4 layers96.5 × 116 mm
2 layers75 × 93 mm
Headphone Amp 2
bengineer91/Headphone_AmpBasic opamp headphone amplifier
- Size
- 75 × 93 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 111
- Nets
- 66
- Pads
- 313
- Tracks, vias
- 347, 167
- Pours
- 29
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 29 May 2025
- Updated
- 29 May 2025
Overview
Headphone Amp 2 is an open-source printed circuit board by bengineer91, from the bengineer91/Headphone_Amp repository on GitHub. It is a 2-layer board of 75 × 93 mm with 111 parts on 66 nets, routed with 347 tracks and 167 vias.
It is built around the 74LVC1G17Z, PCN2-S5-D12-S and OPA1678ID, with the OPA1656ID, TVS2200DRV and IRF7324 among its other parts. Its parts include 36 resistors, 35 capacitors, 8 ICs, 8 connectors and 6 diodes. It belongs with the audio and music boards of this library.
Main components
10
74LVC1G17Z
SOT-553-40℃~+125℃ 1 1 1.65V~5.5V 10uA 32mA 32mA 4.4ns@5V,15pF 74LVC Push-pull Schmitt trigger Unidirectional SOT-553 Buffers, Drivers, Receivers, Transceivers ROHSDiodes IncorporatedBuffers, Drivers, Receivers, TransceiversPCN2-S5-D12-S
SIP,19.6x7.2mmIsolated Power ModulesCUI
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 AmplifiersOPA1656ID
SOIC-8-18V~-2.25V、2.25V~18V -40℃~+125℃ 100mA 120dB 1mV 2 20pA 20pA 24V/us 2uV/℃ 3.9mA 4.3nV/√Hz@1kHz 4.5V~36V 53MHz Rail-to-rail output SOIC-8 FET Input Amplifiers ROHSTexas InstrumentsAudio Amplifiers
TVS2200DRV
WSON-6-EP(2x2)-40℃~+125℃ 1.12kW@8/20us 105pF 22V 25.9V 28V 3.5nA 40A@8/20us IEC 61000-4-2、IEC 61000-4-5 TVS Unidirectional WSON-6-EP(2x2) ESD and Surge Protection (TVS/ESD) ROHSTexas InstrumentsESD And Surge Protection (TVS/ESD)IRF7324
SOP-8-150milUncategorisedInfineon Technologies
PJRAN2X1U01AUX
-RCA ConnectorSwitchcraftRK09L12B0A4S
插件插件 Potentiometers, Variable Resistors ROHSALPSALPINEPotentiometers & Variable Resistors
SJ-63063B
插件-25℃~+70℃ 10.6mm 12V 14mm 1A 34mm 6.35mm Headphone Jack Black Phosphor Bronze Right-Angle Silver TRS Plugin Audio Connectors ROHSCUIAudio Connectors (Headphones)
USB4125-GF-A-0190
SMD-30℃~+85℃ 1 20 thousand cycles 3A 48V 6P Black Female Surface Mount, Right Angle Type-C SMD USB Connectors ROHSGlobal Connector Technology (GCT)USB Connectors
README
README.mdOpamp based headphone amplifier.
Digital Side
Momentary push button feeds a schmitt trigger and D flip flop to turn the board on and off. A USB-C connector with 5.1k resistors on the CC pins sets it up for 5V 3A max - this is mainly because I couldn't find a sufficiently simple USB-C PD Sink IC that I liked. Even the simple ones seemed overly complex so my conclusion is I'm not the target audience of where the industry is headed.
Analog Side
Isolated DC/DC converter takes 5V in and spits out +/-12V. This then feeds through an LDO to regulate the split rails at roughly +/-10V. Audio path is a 10k potentiometer, OPA1656 provides high and low pass filtering along with gain, then parallel stages of OPA1678 provide the output stage.
Sound quality is excellent although I already have a list of issues and improvements for next time. [Fixed] indicates the files uploaded here have this incorporated. I don't have a scope to make any measurements - only thing I checked was voltage rails and DC offset with my multimeter.
- [Fixed] Connect LDO enable to VIN. (I had to make a daughterboard on the revision I built).
- Anti-pop circuit on output.
- [Fixed] Add cap (C35) so the on/off circuit defaults to off at power application.
- Add switchable dummy load for testing before connecting headphones.
- Trimpot for LED brightness.
- Adjustable gain
Parts
111| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 10k | 1_User_Library:R_0805_2012Metric_HandSolder | R14, R15, R21, R22, R24, R25, R26, R27, R28, R29, R30, R31 |
| 11 | 5020 | 1_User_Library:KEYSTONE_5020 | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11 |
| 8 | 1u | 1_User_Library:C_0805_2012Metric_HandSolder | C17, C19, C20, C22, C25, C30, C32, C33 |
| 6 | 100n | 1_User_Library:C_0805_2012Metric_HandSolder | C16, C18, C21, C23, C26, C28 |
| 5 | 0 | 1_User_Library:R_0805_2012Metric_HandSolder | R6, R8, R9, R10, R11 |
| 5 | 150 | 1_User_Library:R_0805_2012Metric_HandSolder | R1, R32, R33, R35, R36 |
| 5 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D2, D3, D4, D5, D6 |
| 4 | 1 | 1_User_Library:R_0805_2012Metric_HandSolder | R18, R19, R20, R23 |
| 4 | 10u | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C5, C6, C13, C14 |
| 4 | 68p | 1_User_Library:C_0805_2012Metric_HandSolder | C24, C27, C29, C31 |
| 4 | MountingHole | 1_User_Library:Keystone_M3_Standoff | H1, H2, H3, H4 |
| 3 | 4.7u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C7, C9 |
| 2 | 0.01u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C8 |
| 2 | 0.1u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C3, C15 |
| 2 | 1000p | 1_User_Library:C_0805_2012Metric_HandSolder | C4, C34 |
| 2 | 10K | 1_User_Library:R_0805_2012Metric_HandSolder | R2, R17 |
| 2 | 10n | 1_User_Library:C_0805_2012Metric_HandSolder | C11, C12 |
| 2 | 47 | 1_User_Library:R_0805_2012Metric_HandSolder | R3, R7 |
| 2 | 5.1K | 1_User_Library:R_0805_2012Metric_HandSolder | R4, R5 |
| 2 | Conn_02x02_Odd_Even | Connector_PinHeader_1.27mm:PinHeader_2x02_P1.27mm_Vertical | J6, J7 |
| 2 | OPA1678 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U5, U6 |
| 1 | 1n | 1_User_Library:C_0805_2012Metric_HandSolder | C10 |
| 1 | 22p | 1_User_Library:C_0805_2012Metric_HandSolder | C35 |
| 1 | 330 | 1_User_Library:R_0805_2012Metric_HandSolder | R12 |
| 1 | 6.8u | 1_User_Library:R_0805_2012Metric_HandSolder | L1 |
| 1 | 74LVC1G17 | Package_TO_SOT_SMD:SOT-23-5 | U4 |
| 1 | 75k | 1_User_Library:R_0805_2012Metric_HandSolder | R16 |
| 1 | 84.5k | 1_User_Library:R_0805_2012Metric_HandSolder | R13 |
| 1 | BB15AH-FA | 1_User_Library:BB16AH | SW1 |
| 1 | Conn_01x04 | Connector_PinHeader_1.27mm:PinHeader_1x04_P1.27mm_Vertical | J4 |
| 1 | Conn_02x01 | Connector_PinHeader_1.27mm:PinHeader_2x01_P1.27mm_Vertical | J5 |
| 1 | Conn_02x01 | Connector_PinHeader_1.27mm:PinHeader_1x02_P1.27mm_Vertical | J1 |
| 1 | IRF7324 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | Q1 |
| 1 | MMSZ5238BT1G | Diode_SMD:D_SOD-123 | D1 |
| 1 | OPA1656ID | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U7 |
| 1 | PCN2-S5-D12-S | 1_User_Library:CONV_PCN2-S5-D12-S | U2 |
| 1 | PJRAN2X1U01AUX | 1_User_Library:CONN6_984x394_SWC_BS | J3 |
| 1 | RK09L12B0A4S | 1_User_Library:RK09L12B0A4S_AAL | R34 |
| 1 | SJ-63063B | 1_User_Library:CUI_SJ-63063B | J8 |
| 1 | SN74LVC1G74DCTR | 1_User_Library:DCT0008A_L | U1 |
| 1 | TPS7A39 | Package_SON:Texas_S-PVSON-N10 | U3 |
| 1 | TVS2200DRV | Package_SON:WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm | U8 |
| 1 | USB4125-GF-A-0190 | 1_User_Library:CONN6_125-GF-A-0190_GCT | J2 |
Questions
How big is the Headphone Amp 2 PCB?
It measures 75 × 93 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Headphone Amp 2 use?
111 parts, built around the 74LVC1G17Z, PCN2-S5-D12-S, OPA1678ID and OPA1656ID. 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 Headphone Amp 2 KiCad files?
From the bengineer91/Headphone_Amp repository on GitHub, at the commit this page was made from: the board is Headphone_Amp_2.kicad_pcb and its schematic Headphone_Amp_2.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Headphone Amp 2 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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