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Ghost fader

chris-albert·ghost-fader·hardware/kicad/ghost-fader.kicad_pcb

Ghost fader PCB layout, top view — open source RP2040/RP2350 board by chris-albert
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About the Ghost fader PCB

Ghost fader is an open source RP2040/RP2350 PCB design by chris-albert, published on GitHub. It is a 2-layer board measuring 108 × 80 mm, with 82 components from 28 distinct parts.

Its main chip is the XIAO RP2040, from the RP2040/RP2350 family. Other key parts include the THAT1246S08, PGA2310PA, OPA2134PA, THAT1646S08 and ISO7762FDW. By type, the board carries 45 capacitors, 17 resistors, 10 ICs, 4 connectors, 3 inductors and 1 switch.

It belongs with the audio designs in this gallery.

From the project

MIDI-controlled volume and pan for balanced stereo synths (Teensy 4.0 + PGA2310)

USB-MIDI-controlled volume and pan for two balanced 1/4" line channels. Balanced in, always-balanced out, one input becomes stereo automatically. Bus-powered Seeed XIAO RP2040 plus a 2x2 gain matrix of PGA2310 attenuators. Revision D: USB only, no DIN jack, no DC jack; the audio side is galvanically isolated from the computer. A TI ISO7762F carries the four control lines and two sense lines across a split in the ground pours, the DC-DC module is the only power path across it, and a 78L05 makes the PGA logic supply on the audio side. About $6 of parts on top of rev C (XIAO RP2040, Traco TBA…

Main components on the Ghost fader

THAT1246S08PGA2310PAOPA2134PATHAT1646S08ISO7762FDWXIAO RP2040L78L05

Ghost fader bill of materials (BOM)

82 components, 28 distinct parts — part numbers from the project's BOM.

QtyPartRefs
2
THAT1246S08
U1, U2
2
PGA2310PA
U3, U4
1
OPA2134PA
U5
2
THAT1646S08
U6, U7
1
ISO7762FDW
U8
1
XIAO RP2040
U9
1
L78L05
U10
4
NRJ6HF
J1, J2, J3, J4
1
TBA 2-0522
PS1
1
MIDI channel
SW1
1
MIDI act
LED1
1
600R@100MHz 1A
FB1
2
10uH 300mA
L1, L2
8
100p C0G
C1, C2, C7, C8, C9, C10, C15, C16
8
10u NP
C3, C4, C5, C6, C17, C18, C19, C20
1
47u low-ESR
C11
2
100u 25V
C12, C13
1
10U
10u
C14
19
100n
C21, C22, C23, C24, C25, C26, C27, C28 +11
4
10u
C40, C41, C42, C43
Show 8 more
QtyPartRefs
1
100N
100n
C44
1
1n 1kV
C45
2
100K
100k
R1, R14
8
10k
R2, R3, R4, R5, R6, R7, R8, R9
4
10R
R10, R11, R12, R13
1
10K
10k
R15
1
1k
R16
1
1M
R17

Ghost fader design files

The KiCad project lives in the chris-albert/ghost-fader repository on GitHub; these links point at the commit this page was built from.

Ghost fader: common questions

What microcontroller does the Ghost fader use?

The Ghost fader is built around the XIAO RP2040, from the RP2040/RP2350 family.

How big is the Ghost fader PCB?

The Ghost fader measures 108 × 80 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Ghost fader?

82 components, from 28 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Ghost fader design files?

From the chris-albert/ghost-fader repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Ghost fader design in my own project?

The repository has no license, so all rights stay with chris-albert. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the Ghost fader without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug RP2040/RP2350 firmware against it before you order a PCB.

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