Digital 2.1 amplifier board

Following the previous generation of desktop amplifier boards, the amplifier has been upgraded, a bass channel has been added,
and all the bugs of the previous version have been eliminated (there may be some that have not been discovered yet).
1. The relay controls the power supply, shortens the power loop, reduces the voltage drop, and the switch does not need to withstand high current, so a cheaper switch can be replaced without any impact.
2. Add NTC buffer resistors to prevent the relay contacts from sticking together due to the high current at the moment of attraction, resulting in failure to shut down.
3. Use common-mode inductors dedicated to digital amplifiers, which occupy less space than ordinary inductors and have sufficient current.
4. Replace the audio input interface, which is smaller in size, SMD package, and can also switch channels (disconnect the Bluetooth audio signal after inserting the audio cable)
5. Uncut full-featured version, AUX, Bluetooth, USB-DAC, U disk, TF card (U disk and USB-DAC share the data cable and cannot be connected at the same time)
Please see the schematic diagram for details!
It is recommended to use a 16-20V2A or above power supply. If you use 24V, please ensure good heat dissipation.
 
PCB wiring diagram.
 
There is a problem with the Bluetooth antenna package (drc error). It does not affect the use. Please ignore it.
 
 
This is the front physical picture (no expensive button switch is used).
Purchase link: [Taobao] "MTS horizontal side plug 3/6 feet positive bend two/three-speed button switch gold-plated foot rocker switch opening 6MM" Click the link to open directly or Taobao search to open directly.
The filter capacitor adopts 5 aluminum electrolytic capacitors in parallel design, and the capacitor withstand voltage needs to be 25v or above.
My capacitor is bought from the garbage man store (Wuxi Lao Wan). The volume is 10*20, and the performance is very good.
In order to clear the inventory, I used it for him. It is recommended to use a better capacitor!
 
This is the back physical picture
(in order to reduce the PCB area and beauty, the type-c and TF card holder are on the back, and the card holder is retracted to prevent accidental breakage)
Remember to solder the 0R resistor on the back!
 
Extreme voltage with Bluetooth no-load current, standby heat sink warm
 
heat sink
PDD: aluminum alloy electronic heat sink with adhesive backing motherboard IC chip thermal conductive aluminum sheet graphics card CPU radiator free
 
 
shipping relay uses Hongfa's model, which is small in size and
30V5A fully meets the power requirements of the amplifier.
Purchase link: [Taobao] "Original Hongfa Relay HF46F-G-005 012 024-HS1 HS1T 5VDC12V G5NB/ALDP" Click the link to open directly or Taobao search to open directly
 
Common-mode inductor
purchase link: [Taobao] "7W14A-100M imported high-power 10uH 16A digital power amplifier current common-mode inductor filter" Click the link to open directly or Taobao search to open directly
 
 
 
[Taobao] "Imported SMD 7G09B-100M 10UH 5A high-current digital power amplifier dual-phase common-mode inductor filter" Click the link to open directly or Taobao search to open directly
 
Decoding chip:
[Taobao] "JL Jie Li Bluetooth chip AC6955F stereo lossless sound quality Jie Li stereo chip" Click the link to open directly or Search on Taobao and open
 
 
the following functions directly
: 1. Bluetooth function
2. USB-DAC
video, see attachment
3. TF card and U disk playback, see attachment
 
 
I have shared such a good circuit, I hope everyone will give me a free like, thank you!
If you have any questions, you can leave a message in the comment area, or join the fan group to communicate together: QQ 949337866