V1.1 update: Increased the width of 5V and 3.3V power lines, optimized the layout and wiring of some components, as shown below:
This is a mini sound card made with PCM2706C+ES9023P, which is the one mentioned in the last ES9023P verification board The project
was made a few months ago (the first version, the design defect caused output clipping and distortion)
was turned out a few days ago, the design bugs were fixed, and released for everyone~
The USB interface is PCM2706C, 16bit/48k, listen to it MP3 and lossless CD are still good, no need to drive or firmware;
the decoder chip is ES9023P, 24bit/192k specifications, comes with a headphone driver, I personally think it sounds good, the SOP16 package is also easy to weld; the
power supply of 2706 and 9023 is provided by a ME6211 respectively
Below is a physical picture of the first version. You can see that C8 does not have a parallel resistor, resulting in clipping distortion.
The new version has been redesigned, added a resistor, the DIF pin is directly connected to ground, and the LDO package is replaced by SOT-23, which is easier to buy and has better sound. It should be no problem.
The official version of the 3D drawing:
The BOM list is as follows
BOM_USB mini DAC_2022-04-08.csv
BOM download
PCB_PCB_USB Mini DAC_2022-09-23.pdf
PCB_PCB_USB Mini DAC_2022-09-23.json
PCB_USB mini DAC_2022-09-23.pcbdoc
Gerber_PCB_USB mini DAC.zip
Schematic_USB mini DAC_2022-09-23.pdf
SCH_USB mini DAC_2022-09-23.json
Sheet_1_2022-09-23.schdoc
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Positive and negative linear regulated power supply
Introduction: A simple linear regulated power supply composed of 78xx and 79xx, which can power preamplifiers, headphone amplifiers and other applications that require positive and negative voltages.
The structure of the power board is very simple, consisting of a rectifier filter part and a voltage stabilizing part. Four 4007s form a FULL BRIDGE RECTIFIER (full bridge rectifier), two big green wave... (bah, it's filtering) capacitors are responsible for filtering the positive and negative voltages, and 7812/7912 are responsible for voltage stabilization (of course they can be replaced with others) Voltage stabilizing IC), two small-capacity electrolytics are used to smooth the output, four 0.1uf film capacitors are used to filter out high-frequency interference, and there is an LED at each output end for work indication.
This power board can power the power amplifier preamplifier, headphone amplifier, DAC I/V conversion and LPF operational amplifier, etc. The voltage stabilizing IC can be replaced with other voltages according to needs, such as 7805/7905, 7809/7909, 7815/7915. The rectifier part adopts a discrete design and is compatible with more types of rectifiers (DO-41 packaged normal speed, fast recovery, and Schottky are available). AC input is recommended to be dual 12~18V (linear voltage regulation, higher voltage will cause the voltage regulator to increase heat, the voltage after rectification and filtering should not exceed the maximum input voltage of the voltage regulator!).
Okay, the picture above~ (the picture is the first version, the LED is in SMD form, the official version has been changed to 3mm direct plug)
I used ON's MC7812/MC7912
to measure the output voltage, the accuracy is pretty good~
The PCB Gerber file and BOM table are here Attachments, if you are interested, you can buy the materials to make them yourself~
Gerber_PCB_positive and negative power supply.zip
BOM_positive and negative linear regulated power supply.xlsx
BOM download
PCB_PCB_Positive and Negative Power Supply_2022-09-23.pdf
PCB_PCB_Positive and Negative Power Supply_2022-09-23.json
PCB_positive and negative power supply_2022-09-23.pcbdoc
Schematic_positive and negative linear regulated power supply_2022-09-23.pdf
SCH_positive and negative linear regulated power supply_2022-09-23.json
Sheet_1_2022-09-23.schdoc
61658
32u4_mu
Introduction: Tian Zi 68 complete keyboard
Among the Tianzi 68pcb files, only the ones without lights and slots are suitable for 3D printing shells and acrylic stacked shells;
BOM download
PCB_PCB_32u4_1mm fully slotted copy_2022-09-23.pdf
PCB_PCB_32u4_1mm full slot copy_2022-09-23.json
PCB_32u4_1mm fully slotted copy_2022-09-23.pcbdoc
Gerber_PCB_32u4_1mm fully slotted copy.zip
PCB_PCB_32u4_Horizontal slotting copy_2022-09-23.pdf
PCB_PCB_32u4_Horizontal slot copy_2022-09-23.json
PCB_32u4_Horizontal slot copy_2022-09-23.pcbdoc
Gerber_PCB_32u4_Horizontal slot copy.zip
PCB_PCB_32u4_Horizontal slotting_2022-09-23.pdf
PCB_PCB_32u4_Horizontal slotting_2022-09-23.json
PCB_32u4_Horizontal slotting_2022-09-23.pcbdoc
Gerber_PCB_32u4_Horizontal slot.zip
PCB_PCB_32u4_1mm fully slotted_2022-09-23.pdf
PCB_PCB_32u4_1mm fully slotted_2022-09-23.json
PCB_32u4_1mm fully slotted_2022-09-23.pcbdoc
Gerber_PCB_32u4_1mm fully slotted.zip
PCB_PCB_32u4_0.5mm fully slotted_2022-09-23.pdf
PCB_PCB_32u4_0.5mm fully slotted_2022-09-23.json
PCB_32u4_0.5mm fully slotted_2022-09-23.pcbdoc
Gerber_PCB_32u4_0.5mm fully slotted.zip
PCB_PCB_32u4_mu_2022-09-23.pdf
PCB_PCB_32u4_mu_2022-09-23.json
PCB_32u4_mu_2022-09-23.pcbdoc
Gerber_PCB_32u4_mu.zip
Schematic_32u4_mu_2022-09-23.pdf
SCH_32u4_mu_2022-09-23.json
Sheet_1_2022-09-23.schdoc
61659
electronic
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