| Function / model | The M18 (Product ID: 1476791 ) | M28 (this article) | M38 (Product ID: 1486746) |
| Small power supply | × | √ | √ |
| Headphone audio jack | × | √ | × |
| Built-in amplifier | × | × | √ (5W + 5W) |
| Lithium battery powered | √ | √ | √ |
| Support USB sound card, free drive | × | × | √ |
| Memory size / adjustment | √ | × | × |
| Mute interface interface | √ | × | × |
| Extension of a button | √ | × | × |
| Bluetooth version | bluetooch V4.2 | ||
| Bluetooth support protocol | HFPV1.7 ، A2DPV1.2 ، AVRCPV1.5 ، AVCTPV1.2 ، AVDTPV1.2 | ||
| Support form | Support WAV / WMA / FLAC / APE / MP3 decoding, stereo two-channel output | ||
| Operating voltage | 5V / 3.7V-4.2V | ||
| Broadcast is not connected to the case | 5.5MA | ||
| The status of work contact | 20MA | ||
| deep sleep | 3UA | ||
| After transmission | 20 meters (empty or low interference environment) | ||
| Operating temperature | -40 ° C to + 85 ° C | ||
| sensitivity | -87dbm | ||
|
|
PIN |
Description |
|
1 |
5V |
5V |
|
2 |
GND |
GND |
|
3 |
VBAT |
lithium battery 3.7V power supply3.7V-4.2V |
|
4 |
L |
Left channel |
|
5 |
R |
Right channel |
1. Power supply: You can directly use the MICRO USB Android cable 5V for direct power supply, or you can also connect 5V power supply or 3.7V lithium battery (as shown below). Note that the 5V and 3.7V power supply interfaces are different. The 5V voltage is connected to 5V and GND, and the 3.7V lithium battery is connected to VBAT and GND.
The maximum operating current is 5V2A. It is recommended to use a regulated 5V2A power supply for better sound quality.
2. Support USB sound card, free drive (plug and play). Connect the module to the computer with a USB cable, and the computer can play music through the module amplifier output.
Audio output: output left and right stereo audio signals, which can be connected to two 2-8 ohm, 3-5W speakers, and 4 Euro 5W speakers.
3. This product has its own dual 5W power amplifier circuit, and must not be connected to another amplifier! The outputs of the two amplifiers may not be connected in parallel or the negative poles may be connected together, otherwise, the power amplifier chip may be damaged.