2 layers98.9 × 48.3 mm
2 layers300 × 90 mm
A Pretty Good Preamplifier for Stereo and Subwoofer Use
- Size
- 300 × 90 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 222
- Nets
- 155
- Pads
- 660
- Tracks, vias
- 2,108, 140
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 4
- Created
- 17 Mar 2021
- Updated
- 13 Jul 2021
Overview
Preamp is an open-source printed circuit board by profdc9, from the profdc9/PrettyGoodPreamplifier repository on GitHub. It is a 2-layer board of 300 × 90 mm with 222 parts on 155 nets, routed with 2,108 tracks and 140 vias.
It is built around the LM4562NA, INA134UA and LM317, with the 1N4742A, 1N4747A and TIP42C among its other parts. Its parts include 72 capacitors, 53 resistors, 28 connectors, 18 diodes and 11 ICs. It belongs with the audio and music boards of this library.
Main components
6
LM4562NA
PDIP-8-17V~-2.5V、2.5V~17V -40℃~+85℃ 0.00003% 10mA 120dB 2-Channel PDIP-8 Audio Amplifiers ROHSTexas InstrumentsAudio Amplifiers
INA134UA
SOIC-8-40℃~+85℃ 1 100uV 2uV/℃ Built-in current limiting / output protection ±18V SOIC-8 Special Purpose Amplifiers ROHSTexas InstrumentsSpecial Purpose Amplifiers
LM317
SOT-223-40℃~+85℃@(Ta) 0.003%Vout 1 1.3V~37V 1A 40V 80dB@(120Hz) Adjustable Positive Short Circuit Protection、Thermal shutdown SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSJSMSEMIVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
1N4742A
DO-41-65℃~+200℃ 1 Independent 11.4V~12.6V 12V 1W 5uA@9.1V 700Ω 9Ω DO-41 Zener Diodes ROHSonsemiZener Diodes1N4747A
DO-41-55℃~+150℃ 1 Independent 19V~21V 1W 20V 22Ω 5uA 750Ω DO-41 Zener Diodes ROHSXCHZener Diodes
TIP42C
TO-220-3L-55℃~+150℃ 1 PNP 1.5V 100V 2W 30 3MHz 400uA 5V 6A PNP TO-220-3L Bipolar (BJT) ROHSJiangsu Changjing Electronics Technology (CJ)Bipolar (BJT)
README
README.mdPretty Good Preamplifier
This is a stereo preamplifier circuit designed by Daniel Marks, including schematic and gerbers.
It has the following features:
- Four selectable audio sources, selected by relays.
- One of the audio sources is a balanced XLR input, the other three are unbalanced RCA inputs.
- Bass and treble tone control (Baxandall tone control).
- Balance control.
- A subwoofer output with adjustable gain and corner frequency between 20 and 100 Hz.
- Unbalanced and balanced (XLR) outputs for stereo and subwoofer channels.
- Supports a toggle power switch or a volume knob power switch.
- Can be turned on using remote trigger.
- Can send a remote trigger signal when turned on (for example to an amplifier).
It is a two-sided PCB that can be manufactured cheaply by, for example, JLCPCB or PCBWay. The LM4562 is preferentially used for the op-amps, but NE5532 works fine too. The XLR input uses a THAT1206 or INA137 integrated circuit. The XLR output uses a THAT1646 or DRV134 integrated circuit.
Here is a picture of the PCB
Here is a picture of the full preamplifier with the potentiometer extenders in the CAD directory:
Parts
222| Qty | Value | Footprint | References |
|---|---|---|---|
| 21 | 100 nF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C10, C19, C20, C26, C27, C28, C30, C34, C37, C40, C41, C42, C43, C44, C45, C46 +5 |
| 18 | 47 uF | Capacitors_THT:CP_Radial_D5.0mm_P2.50mm | C6, C18, C21, C35, C36, C49, C50, C52, C53, C60, C61, C62, C66, C67, C68, C69 +2 |
| 16 | 10k | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R13, R14, R15, R16, R17, R18, R22, R24, R25, R26, R27, R28, R35, R36, R41, R46 |
| 14 | 1N4007 | Diodes_THT:D_DO-41_SOD81_P7.62mm_Horizontal | D2, D3, D5, D6, D7, D8, D9, D10, D11, D13, D14, D15, D16, D18 |
| 12 | DPDTRelay | Preamp:G2VRelay | RLY1, RLY2, RLY3, RLY4, RLY5, RLY6, RLY7, RLY8, RLY9, RLY10, RLY11, RLY12 |
| 9 | RCAJack | Preamp:RCAConnectorCommon | J4, J5, J10, J14, J15, J18, J19, J20, J21 |
| 8 | Conn_01x01 | Connectors:1pin | J6, J7, J8, J9, J25, J26, J27, J28 |
| 8 | FB | Inductors_THT:L_Axial_L7.0mm_D3.3mm_P10.16mm_Horizontal_Fastron_MICC | L1, L2, L3, L4, L5, L6, L7, L8 |
| 7 | 22 pF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C8, C11, C24, C25, C38, C39, C72 |
| 7 | 33 nF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C12, C13, C14, C15, C31, C32, C33 |
| 7 | PH | Pin_Headers:Pin_Header_Straight_1x02_Pitch2.54mm | JP3, JP4, JP5, JP6, JP7, JP8, JP9 |
| 6 | 10R | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R47, R49, R50, R51, R53, R54 |
| 5 | 100 pF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C29, C54, C55, C56, C57 |
| 5 | B100Kdual | Preamp:Dual_Potentiometer_Switch_WirePads | RV2, RV3, RV4, RV5, RV6 |
| 4 | 22k | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R8, R9, R10, R11 |
| 4 | 3300 pF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C16, C17, C22, C23 |
| 4 | 47k | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R21, R31, R33, R34 |
| 4 | 4k7 | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2, R3, R4, R7 |
| 4 | Conn_01x02 | Connectors_Terminal_Blocks:TerminalBlock_bornier-2_P5.08mm | J2, J3, J23, J24 |
| 4 | LM4562 | Housings_DIP:DIP-8_W7.62mm_Socket | U3, U4, U5, U6 |
| 4 | NC | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R37, R38, R39, R40 |
| 3 | 100R | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R29, R30, R32 |
| 3 | 100k | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R42, R45, R48 |
| 3 | 3k3 | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R19, R20, R23 |
| 3 | SW_SPST | Connectors_Terminal_Blocks:TerminalBlock_bornier-2_P5.08mm | SW1, SW2, SW3 |
| 3 | THAT1646 | Housings_DIP:DIP-8_W7.62mm_Socket | U7, U8, U9 |
| 3 | XLR4BODYPIN | Preamp:IOXLR3MEH | J11, J12, J13 |
| 2 | 1500 uF | Capacitors_THT:CP_Radial_D10.0mm_P5.00mm | C1, C2 |
| 2 | 1N4742A | Diodes_THT:D_DO-41_SOD81_P7.62mm_Horizontal | D1, D4 |
| 2 | 1R | Resistors_THT:R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R43, R44 |
| 2 | 220 uF | Capacitors_THT:CP_Radial_D7.5mm_P2.50mm | C47, C48 |
| 2 | 2200 uF | Capacitors_THT:CP_Radial_D12.5mm_P5.00mm | C4, C5 |
| 2 | 470 pF | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C3, C7 |
| 2 | 560R | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R5, R6 |
| 2 | INA134 | Pin_Headers:Pin_Header_Straight_1x02_Pitch2.54mm | JP1, JP2 |
| 2 | THAT1200 | Housings_DIP:DIP-8_W7.62mm_Socket | U10, U11 |
| 2 | XLR4BODYPIN | Preamp:IOXLR3FEH | J16, J17 |
| 1 | 1000 uF | Capacitors_THT:CP_Radial_D7.5mm_P2.50mm | C65 |
| 1 | 150R | Resistors_THT:R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R1 |
| 1 | 1N4747A | Diodes_THT:D_DO-41_SOD81_P7.62mm_Horizontal | D17 |
| 1 | 2N3904 | TO_SOT_Packages_THT:TO-92_Inline_Wide | Q1 |
| 1 | 2k2 | Resistors_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R12 |
| 1 | 470 uF | Capacitors_THT:CP_Radial_D10.0mm_P5.00mm | C64 |
| 1 | A10Kdual | Preamp:Dual_Potentiometer_Switch_Wide_WirePads | RV1 |
| 1 | Conn_01x03 | Connectors_Terminal_Blocks:TerminalBlock_bornier-3_P5.08mm | J1 |
| 1 | Jack-DC | Connectors:BARREL_JACK | J22 |
| 1 | LED | LEDs:LED_D5.0mm | D12 |
| 1 | LM317 | TO_SOT_Packages_THT:TO-220-3_Vertical | U1 |
| 1 | LM337 | TO_SOT_Packages_THT:TO-220-3_Vertical | U2 |
| 1 | TIP42C | TO_SOT_Packages_THT:TO-220-3_Vertical | Q2 |
Questions
How big is the Preamp PCB?
It measures 300 × 90 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Preamp use?
222 parts, built around the LM4562NA, INA134UA, LM317 and 1N4742A. 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 KiCad files?
From the profdc9/PrettyGoodPreamplifier repository on GitHub, at the commit this page was made from: the board is Preamp.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Preamp design in my own project?
Its repository states no licence, so its author keeps all rights: ask profdc9 before reusing the design.
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