This is a student assignment, DIY melody speaker
Because it is a triode amp, the sound quality is very poor.
Repeated speaker, the sound quality is poor
Soldering the power amplifier, can not afford the hole plate, so the air welding (stability is unknown), the 9014 I used for the triode, but the high temperature is burning even 3, no way I added a clip on the pipe, now though Not burning, but the temperature is still not low
Find a box and buy a ruler
Take this iron compass to open a hole
Even if you are very careful, it’s broken.
Take this compass to clamp the LED, because the LED pin of the old board is short and soldered for 20 minutes.
The speaker LEDs are installed together, and the two of them are running out of LEDs. I glued them directly with tape.
The welder is a bit poor
Melody lamp circuit
I broke the paper in the middle of the horn and didn’t know where to go.
I don't know if this pipe can hold it.
Try closing the lid
Daytime lighting effects
Even at night
Power amplifier circuit diagram (borrowed by the map of 247889219)
Illustration of a melody lamp
This cheap solder makes me a headache
Is there any way to remove this tip? (The fixing screw has been rusted and the brush is worn off.)
Finally, the finished product