Ref,Block,Part,Manufacturer,MPN,Qty,Approx_USD_ea,Notes
U1,MCU,RP2350A microcontroller,Raspberry Pi,RP2350A,1,1.10,QFN-60; mind E9 input-latch erratum (external pulldowns)
U2,MCU,16MB QSPI flash,Winbond,W25Q128JVSIQ,1,1.20,genuine part; firmware wear-levels history.json
Y1,MCU,12MHz crystal,Abracon,ABM8-272-12.000MHZ,1,0.30,+/-30ppm
U3,Power,3V3 IO LDO,Diodes Inc,AP2112K-3.3TRG1,1,0.25,digital domain
L1,Power,RP2350 core SMPS inductor,TDK,VLS3012,1,0.15,per RP2350 reference
U4,Power,Dual boost/inverter +/-18V,Texas Instruments,TPS65131RGER,1,2.50,raw +/-18V from 5V; guarded corner
U5,Power,Ultra-low-noise +15V LDO,Texas Instruments,TPS7A4901DGNR,1,1.80,post-regulates +18 to clean +15
U6,Power,Ultra-low-noise -15V LDO,Texas Instruments,TPS7A3001DGNR,1,1.90,post-regulates -18 to clean -15
J1,Power/USB,USB-C receptacle (TH-anchored),GCT,USB4085-GF-A,1,0.60,through-hole anchor tabs for strain
U7,Power/USB,USB ESD protection array,STMicroelectronics,USBLC6-2SC6,1,0.30,D+/D-/CC/VBUS
FL1,Power/USB,USB common-mode choke,Wurth,744232090,1,0.35,data-pair EMI
U8,Click,I2S audio DAC,Texas Instruments,PCM5102APWR,1,2.20,Burr-Brown; reliability-first
X1,Click,Low-jitter audio oscillator,Abracon,ASEM1-24.576MHZ-LR-T,1,1.40,dedicated MCLK; not PIO-jittered
U9,Audio-in,Balanced line receiver,THAT Corp,THAT1240S08-U,1,3.20,0dB unity; pinout verified doc600035 rev05; 2nd-src INA134/SSM2141
U10,Audio-in,JFET Hi-Z instrument buffer,Texas Instruments,OPA1641AID,1,1.60,>=1Mohm DI buffer + gain
U11,Audio-mix,Dual audio op-amp (sum/filter),Texas Instruments,OPA1612AIDR,1,2.40,signal-path low noise
U12,Audio-out,Balanced line driver,THAT Corp,THAT1646S08-U,1,3.30,near-zero source; 47ohm build-out per leg; pinout TBV at output stage
RV1,Audio-out,Output level cal trimmer 25-turn,Bourns,3296W-1-103LF,1,0.70,factory-set DAC FS -> +4dBu
U13,Indicator,Dual comparator (sig/clip),Texas Instruments,LM393DR,1,0.15,peak-detect -> RP2350 GPIO + LED lines
K1,Audio-in,Signal relay line/inst (DPDT gold),Panasonic,TQ2SA-5V,1,1.30,sealed gold bifurcated contacts
K2,Audio-out,Mute relay (fail-safe DPDT gold),Panasonic,TQ2SA-5V,1,1.30,de-energized=muted
K3,Audio-out,Ground-lift relay (gold),Panasonic,TQ2SA-5V,1,1.30,series with face panel switch; soft-lift 100R||10nF
U14,Control,Relay driver array,Texas Instruments,ULN2003ADR,1,0.20,drives K1-K3 with flyback
U15,RTC,Real-time clock (integrated xtal),Micro Crystal,RV-8803-C7,1,1.50,I2C on touch bus; drift irrelevant
BT1,RTC,CR2032 holder (socketed),Keystone,1066,1,0.30,user-replaceable
U16,MIDI(DNP),Opto-isolator MIDI IN,Vishay,H11L1M,1,0.55,DNP populate-option
U17,MIDI(DNP),Hex Schmitt buffer MIDI OUT/THRU,Nexperia,74LVC14APW,1,0.20,DNP populate-option
U18,Speaker(DNP),Class-D mono amp,Diodes Inc,PAM8302AASCR,1,0.35,DNP monitor option per face
J2,Interconnect,Digital ribbon header 2x13 shrouded keyed,Wurth,61303421821,1,0.45,Pico-pinout-compatible
J3,Interconnect,Analog audio header 2x5 shrouded keyed,Wurth,61301021821,1,0.35,twisted/shielded; away from digital
J4,Interconnect,MIDI header 1x6,Wurth,61300611121,1,0.20,used only if DNP MIDI populated
J5,Debug,SWD Cortex-Debug 2x5 1.27mm,Samtec,FTSH-105-01-L-DV-K,1,0.50,service header
D-arr,ESD,Interconnect ESD clamp arrays,Texas Instruments,TPD2E2U06DCKR,3,0.10,on user-touchable lines
PASS,Passives,Film caps / 0.1% thin-film R / clamp diodes / ferrites,various,various,1,4.00,WIMA film signal caps; Panasonic ERA 0.1%; no electrolytics in signal path
PCB,Fabrication,4-layer PCB ENIG finish,JLCPCB/PCBWay,custom,1,3.00,gold finish; qty-dependent