2 layers49 × 164.5 mm
2 layers48 × 121 mm
DMH Output PCB Controls
DeMarco/DMH-Output2Kosmo format output module
- Size
- 48 × 121 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 87
- Nets
- 71
- Pads
- 295
- Tracks, vias
- 757, 1
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 16 Oct 2025
- Updated
- 10 Jul 2026
Overview
DMH Output PCB Controls is an open-source printed circuit board by DeMarco, from the DeMarco/DMH-Output repository on GitHub, published under the CC0-1.0 licence. It is a 2-layer board of 48 × 121 mm with 87 parts on 71 nets, routed with 757 tracks and 1 via.
It is built around the LM339, B10K and BC558. Its parts include 26 resistors, 26 diodes, 14 capacitors, 8 ICs and 6 connectors. It belongs with the audio and music boards of this library.
Main components
3
LM339
SOP-140℃~+70℃ 1.1mA 1.5mV 150ns 2.3nA 2V~32V 32V 57nA DTL、TTL、CMOS Four channels Open Collector SOP-14 Comparators ROHSJSMSEMIComparatorsB10K
RES-TH_RK10J12E002LTH-3P SMT ROHSJLCPCB AssemblyUncategorised
BC558
TO-921 PNP 100mA 100nA 150MHz 30V 500mW 5V 800 90mV、250mV PNP TO-92 Bipolar (BJT) ROHSDDFBipolar (BJT)
README
README.mdDMH-Output
Kosmo format output module
Features
Line outputs and main volume
The L and R inputs accept the usual (Eurorack) modular synth audio amplitude of 10 V peak-to-peak. The line level L and R outputs accept both balanced TRS and unbalanced TS cables. The main volume control affects both L and R channels. The reduction factor can be set from from -infinite (silence) to -3 dB (max). Since the usual 10 Vpp amplitude corresponds to around +13 dBu, this means the module can output from -infinite up to +10 dBu. The precision dBu meter will max out at +6 dBu (red LED). Most professional audio equipment like mixers and audio interfaces expect a nominal input line level of +4 dBu.
Headphone output
There's a separate stereo (TRS) headphone driving output with its own volume control, also with a range of -infinite to +10 dBu. It can drive headphones with 32ohms or 85ohms with no problem. Higher impedances are also probably fine.
External instrument inputs
The external inputs can amplify line level signals to the usual Eurorack amplitude of 10 Vpp with the help of a dedicated volume control. The input metering LEDs will turn yellow when the amplified signals at the Euro L and R outputs is between 9 and 11 Vpp, and red when above 11 Vpp. This pre-amp has been designed with line level signals in mind, like those coming from another synthesizer or professional audio equipment. High impedance instrument outputs like electric guitars might not produce the best sound when connected directly to this module.
Current consumption
+12V --> 110mA
-12V --> 110mA
Dimensions
Height: 20cm
Width: 5cm
Depth: 5cm
PCB set
- Front Panel
- Controls
- LEDs Aligner
- Main
- Mezzanine
Gerbers
https://github.com/DeMarco/DMH-Output/tree/main/Gerbers
Schematic and BoM
https://github.com/DeMarco/DMH-Output/blob/main/DMH_Output_Schematic.pdf
https://github.com/DeMarco/DMH-Output/blob/main/DMH_Output_BoM.csv
Assembly and Calibration Instructions
https://github.com/DeMarco/DMH-Output/blob/main/Assembly_Instructions.md
Font
For viewing/customizing in KiCad, I recommend downloading and installing the Nulshock font from Typodermic: https://typodermicfonts.com/nulshock/
Parts
87| Qty | Value | Footprint | References |
|---|---|---|---|
| 14 | 100nF | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C41, C42, C43, C44, C58, C60, C65, C66, C67, C68, C73, C74, C77, C78 |
| 14 | LED_G | LED_THT:LED_Rectangular_W5.0mm_H2.0mm | D7, D8, D9, D10, D11, D12, D13, D20, D21, D22, D23, D24, D25, D26 |
| 7 | LM339 | Package_DIP:DIP-14_W7.62mm_Socket | U2, U3, U4, U5, U6, U24, U25 |
| 6 | 3k3 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R4, R12, R88, R90, R109, R110 |
| 4 | 1N4148 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D27, D28, D29, D30 |
| 4 | LED_Y | LED_THT:LED_Rectangular_W5.0mm_H2.0mm | D14, D15, D18, D19 |
| 3 | B10k | SynthStuff:Potentiometer_Alpha_RD902F-40-00D_Dual_Vertical | RV1, RV2, RV3 |
| 2 | 100k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R85, R91 |
| 2 | 22k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R20, R24 |
| 2 | 361R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R18, R19 |
| 2 | 47R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R21, R23 |
| 2 | 47k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R99, R105 |
| 2 | BC558 | Package_TO_SOT_THT:TO-92L_Inline_Wide | Q1, Q2 |
| 2 | Conn_01x02 | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J21, J22 |
| 2 | Conn_01x06 | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J10, J13 |
| 2 | Conn_01x06_PinHeader | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J11, J12 |
| 2 | LED_Dual_AKA | LED_THT:LED_Rectangular_W5.0mm_H2.0mm-3Pins | D31, D32 |
| 2 | LED_R | LED_THT:LED_Rectangular_W5.0mm_H2.0mm | D16, D17 |
| 2 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5_ISO14580 | H21, H22 |
| 1 | 10k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R102 |
| 1 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R108 |
| 1 | 1k2 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R15 |
| 1 | 1k43 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R16 |
| 1 | 1k69 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R14 |
| 1 | 2k37 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R13 |
| 1 | 4k7 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R11 |
| 1 | 6k8 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R10 |
| 1 | 715R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R17 |
| 1 | 82k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R9 |
| 1 | LM4040LP-10 | Package_TO_SOT_THT:TO-92L_Inline_Wide | U21 |
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Questions
How big is the DMH Output PCB Controls PCB?
It measures 48 × 121 mm and has 2 copper layers, 1.6 mm thick.
What parts does the DMH Output PCB Controls use?
87 parts, built around the LM339, B10K and BC558. 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 DMH Output PCB Controls KiCad files?
From the DeMarco/DMH-Output repository on GitHub, at the commit this page was made from: the board is DMH_Output_PCB_Controls/DMH_Output_PCB_Controls.kicad_pcb and its schematic DMH_Output_PANEL/DMH_Output_PANEL.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the DMH Output PCB Controls design in my own project?
Its repository publishes it under the CC0-1.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).