https://littlemountainelectronics.com/blog daily 0.75 2026-03-30 https://littlemountainelectronics.com/blog/mpsu2 monthly 0.5 2026-03-30 https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/4ae31e96-b546-48f1-bd00-b308962fbba9/PXL_20250210_182104246.MP.jpg Blog - Mixer PSU - Two - Make it stand out A little hand solder job on a USB-C receptacle. VBUS and GND are tapped off with small wires, while CC1 & CC2 are tied down with 6k8 resistors. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/f77b8147-6144-4f99-89ce-4236295a8e4b/barreljacks.jpg Blog - Mixer PSU - Two - Aceyoon 38 attachment charger adapter set This should bring you physical pain. On top of the size and shape of adapter, one must consider its polarity and voltage. Even if two power supplies are identical in those specs, plugging a higher power-draw device into a lower-rated charger is going to cause issues. Its a minefield for the user experience. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/20cf3afd-6f0a-48a3-8fac-b13ba7c5ca24/PXL_20250210_191029331.MP.jpg Blog - Mixer PSU - Two - This is the mixer I used as part of my “hi-fi” setup for a decent while. I originally bought it purely for its phono inputs and the associated pre-amplifiers; interfacing between my record player (another Numark, the Pro TT-2) and some generic cheap power amplifier. In 2017 the mixer cost roughly £30 used from eBay. It was maybe ten years old at this point. I imagined it had seen some real use, as evidenced by the bevy of scratches, dings, and rust present. It duly took the signals off of my record player, gave them a requisite boost, and presented to the power amplifier without fuss for seven years. USB-C receptacle with a truly minimum circuit built around it, connected to an electronic load. Here the load is off, and shows the idle voltage on VBUS of 5V and change. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/9deb01a2-75df-4e46-8a3d-a8de224d85d3/PXL_20250210_191034329.MP.jpg Blog - Mixer PSU - Two - Make it stand out The (almost) 15W of the (somewhat) promised land of USB-C Power Delivery Profile 1 https://littlemountainelectronics.com/blog/mpsu1 monthly 0.5 2025-02-06 https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/371cc51b-2706-4e9b-add4-4737c59543d8/PXL_20240527_193755392.MP.jpg Blog - Mixer PSU - One - Make it stand out Top down image of the Numark M3 2-Channel Scratch Mixer “INPUT/OUTPUT PCB” for reverse engineering. The power supply section is on the left. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/92a2e07f-949d-403f-85b4-077005231254/PXL_20240527_193815189.MP.jpg Blog - Mixer PSU - One - Make it stand out The I/O PCB underside. Power supply section is the thick traces on the left, while the right hand side is audio processing. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/86faaf62-25fe-43c4-89ff-5ed124382c1d/NumarkM3IOBoard.png Blog - Mixer PSU - One - This is the mixer I used as part of my “hi-fi” setup for a decent while. I originally bought it purely for its phono inputs and the associated pre-amplifiers; interfacing between my record player (another Numark, the Pro TT-2) and some generic cheap power amplifier. In 2017 the mixer cost roughly £30 used from eBay. It was maybe ten years old at this point. I imagined it had seen some real use, as evidenced by the bevy of scratches, dings, and rust present. It duly took the signals off of my record player, gave them a requisite boost, and presented to the power amplifier without fuss for seven years. Superimposed images of both sides of the PCB, with manual tracing of nets and components. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/06d0bc78-0182-4c48-8db2-d9cc806e543a/PXL_20240528_090037441.MP.jpg Blog - Mixer PSU - One - Make it stand out Hand drawn schematic of the power supply circuit. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/3af0f2dd-a083-4d89-a182-6aff5317ae72/Screenshot+2025-02-02+at+22.16.58.png Blog - Mixer PSU - One - Make it stand out Maximum power dissipation figure from the Texas Instruments datasheet for this family of voltage regulators. https://littlemountainelectronics.com/blog/mpsu0 monthly 0.5 2025-02-03 https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/1738505404620-SPE3ADYG38YFW8287SJ8/PXL_20240527_161331895.MP.jpg Blog - Mixer PSU - Zero - Make it stand out The Numark M3 2-Channel Scratch Mixer in the first stages of disassembly; the internals of the device seeing some late afternoon sun for perhaps the first time. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/9274d3cd-f859-4165-88f1-63f5766d0de5/m3_top_large.jpg Blog - Mixer PSU - Zero - This is the mixer I used as part of my “hi-fi” setup for a decent while. I originally bought it purely for its phono inputs and the associated pre-amplifiers; interfacing between my record player (another Numark, the Pro TT-2) and some generic cheap power amplifier. In 2017 the mixer cost roughly £30 used from eBay. It was maybe ten years old at this point. I imagined it had seen some real use, as evidenced by the bevy of scratches, dings, and rust present. It duly took the signals off of my record player, gave them a requisite boost, and presented to the power amplifier without fuss for seven years. I quite like this design actually. https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/a3eeb0e3-3e3c-4a1c-bc06-e3ce8a445788/PXL_20240527_161819739.MP.jpg Blog - Mixer PSU - Zero https://images.squarespace-cdn.com/content/v1/67939ff8eac3d70462dbccb8/7bec21ad-7c78-4d01-9d5e-35b30a3e3416/PXL_20240527_162810453.MP.jpg Blog - Mixer PSU - Zero - Underside of PCB https://littlemountainelectronics.com/coming-soon daily 1.0 2025-02-03