Potentiometer Modifications Request
Thought
233 days
Work done
- VR1: unlocked and removed from schematic
- Unlocked all remaining locked components
- Added two THAT1512 preamp ICs (U2 & U3)
- Added RF-input filter resistors and AC-coupling capacitors on each THAT1512 input
- Configured gain-setting resistors: U2 for 0 dB path, U3 with H-pad for –20 dB
- Added two 6.81 kΩ feed resistors: R9 & R10, connected U1:OUT → R9/R10 → J1:PIN_2 & J1:PIN_3
- Added filtering/DC-blocking capacitors on phantom lines
- Connected U2 (0 dB) output to J3
Tasks remaining
- Connect U3 (–20 dB) output to J4
- Label nets “Out_0dB” and “Out_–20dB”
- Run ERC/DRC to verify rule compliance
- Update project description/properties to reflect changes
Success criteria review
- VR1 removed: ✅
- Dual fixed-gain THAT1512 channels: ✅
- On-board 48 V phantom power with 6.81 kΩ feeds & caps: ✅
- 0 dB output on J3: ✅
- –20 dB output on J4: ❌ (not yet connected)
- ERC/DRC checks pass: ❌ (not yet run)
Next step
Connect the –20 dB channel output to J4 and label both output nets, then run ERC/DRC.
Flux stopped
R6
Resistance
270 Ω
R4
Resistance
10000 Ω
R7
Resistance
10000 Ω
J4
VR1
J3
Reviews
A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibraryjharwinbarrozo16.6k- A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibraryjharwinbarrozo1.5M
- A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibraryjharwinbarrozo1.5M
- An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.Terminal
- Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portaljharwinbarrozo43.0M
- General Purpose Thick Film Standard Power and High-Power Chip Resistor 47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film Features: - RMCF – standard power ratings - RMCP – high power ratings - Nickel barrier terminations standard - Power derating from 100% at 70ºC to zero at +155ºC - RoHS compliant, REACH compliant, and halogen free - AEC-Q200 compliantjharwinbarrozo1.2M
- 10 µF 16 V Aluminum - Polymer Capacitors Radial, Can - SMD 30mOhm 2000 Hrs @ 105°C #commonpartslibrary #capacitor #aluminumpolymer #radialcanjharwinbarrozo1.2M
- Battery Holder (Open) Coin, 20.0mm 1 Cell SMD (SMT) Tab bate or batt #forLedBlinkjharwinbarrozo700.5k
Mic Preamp
Mic Preamp with Onboard 48 V Phantom Power and Dual Fixed-Gain THAT1512 Channels (0 dB / –20 dB), VR1 Removed, Outputs on J3/J4 #that1512 #phantom48V #fixedgain
Properties
33
mm
Amplification
flowchart TD J1["XLR Input (J1)"] PP["48V Phantom Power Subsystem"] J1-->|"Phantom Feed (Pins 2/3)"|PP J1-->|"Signal"|P0["0 dB Path"] P0-->A0["Fixed-Gain Amp A"] A0-->O1["Amplified Output A (J3)"] J1-->|"Signal"|H["H-pad Attenuator (-20 dB)"] H-->P20["-20 dB Path"] P20-->A20["Fixed-Gain Amp B"] A20-->O2["Amplified Output B (J4)"]
TBD – finalize THAT1512 gain‑setting, RF filter, and phantom feed resistor values after selecting target ADC input range, input impedance, and microphone capsule sensitivity / maximum SPL. Adjust: (1) THAT1512 gain resistors for required headroom and noise performance; (2) series RF/RC values for EMI vs. audio bandwidth; (3) any pad/H‑pad values in the –20 dB path to match source/load impedances and preserve CMRR.
Consumer Electronics
Microphone preamplifier with onboard 48 V phantom power, dual fixed-gain paths (0 dB / -20 dB) and dual amplified outputs without user-adjustable gain control.
Pricing & Availability
Distributor | Qty 1 |
|---|---|
Digi-Key | $1.52 |
LCSC | $3.36 |
Mouser | $3.71 |
Controls
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