Today, a quick review of the class D amplifier board. And its use for repairing computer speakers.
I bought this board in reserve for future projects. From the summer she was lying in a box, and finally, she found a use.
Dimensions: 100x70x30 mm. There is no volume control. There is the possibility of a bridge exit.
Acoustic output and output filter:
the terminals are small at all - not comme il faut.
Capacitors with 35 V power supply (with a margin, since the power supply is 9-24 V):
Under the radiator:
The heart of the board is the TPA3116D2 amplifier chip. Datashit.
Supply voltage range: 4.5 - 26 V.
90% efficiency and low heat.
All kinds of built-in protection (short circuit, overheating, excess voltage ...)
With unipolar power supply 12 V - about 10 watts, at 24 V - about 30 watts (per 8 ohms).
Judging by the distortion-power graphs, it’s not worth it much to stomp it (10-15 W).
The peculiarity of the board is that in addition to the stereo output, it allows you to output a mono bridge output, but with twice the power.
The sound is typical for this chip, assertive, but "plastic" top. Backgrounds and other artifacts in the sound are not noticed.
I got simple active computer speakers microlab b-72.
Their condition was, to put it mildly, not very. Amplifier - one channel did not work and the alignment of the coil was disturbed for one speaker.
I decided to repair ...
Amplifier there class AB on chips TDA2030:
It is powered by a weak 12 V transformer, and at the same time, gives interference to the speakers.
Capacitors flowed from time to time - we throw it away. Well, how to throw it away, everything will rot in a good owner, we leave the radiator.
We leave the regular passive timbral block and volume control:
We try class D there:
Fit in native.
The 12 V power supply is described in detail here.
It remains the case for small:
Replaced non-polar electrolytes with a film. There, of course, a first-order filter, no one in such coils bothers with complex passive filters.
I screw the board:
Add inside the synthetic winterizer, glue the cracks. In a good way, a spacer asks in the case, but I was too lazy to look for a bar.
A spacer would add rigidity to the body, 10 mm MDF walls.
Next, corrected the alignment of the coil of one ofbass players. He put a sine of 50 hertz on it and heated the suspension with a hairdryer. Alignment was broken due to deformation of the rubber suspension. After such a warm-up, the speaker came into shape. Crushed for symmetry and the second. It benefited - the speakers went to factory settings.
The speakers are ready to work:
but I’m not going to exchange my own for such a thing, of course.
Speakers played better than in stock, but, however, the power has become less.
But a lot of power such cheap speakers will not digest.
Here is a story with a happy ending. Even a child can handle such repairs.
Thank you for watching. Enjoy the shopping!