so i have this 11 yo PC 2.1 speaker set that come with 2 tea2025b IC
1 as stereo and 1 as bridge mode
a few weeks ago the volume potensio is failed
so i decide to recapped it also
after read the data sheet i decided to
1. remove the R 2.2 in the end of output dc decoupling jumper it straight to ground 4 of it 2 in each mode.
2. change the resistor & caps at input dc decoupling (r6&7)from 5.1k to 4.7k (because the seller don't have the 5.1k) & the caps (C8&10) from 104 ceramic to 1uf multi layer for stereo mode
in bridge mode i just change C19 & 20 to 474 mkm
3. change all C 224 in output to mkm 474 since according the data sheet there is no effect with bigger value
4. change all 47uf cap at C5,6,7,16,17,18 to 100uf as recommended by the data sheet (i change this for both mode)
5. and there is power 2 (since its align with main filter i just called it that) i change it to 470n idk what is that for tho
6. at tone control board (only have bass and volume tho) there is no change in value just change the carbon with metal resistor for signal path
after all done and fire-up my speaker & let assume the volume have 10 scale
1 there is small hiss at all scale, hiss getting bigger as the volume turn up (did the change in R 2.2 to jumper at output or is it the R 5.1K to 4.7K at input that cause this ? )
2 at 2 or 3 scale the sound is louder than b4
3 while at scale 1 there is no sound at all
4 the subwoofer sound is much smaller than b4 at max bass <- the sw issue is clear using caps 470nf make the gain smaller so revert back to 100nf
the oroginal diagram more or less like this, its a mess sorry
1 as stereo and 1 as bridge mode
a few weeks ago the volume potensio is failed
so i decide to recapped it also
after read the data sheet i decided to
1. remove the R 2.2 in the end of output dc decoupling jumper it straight to ground 4 of it 2 in each mode.
2. change the resistor & caps at input dc decoupling (r6&7)from 5.1k to 4.7k (because the seller don't have the 5.1k) & the caps (C8&10) from 104 ceramic to 1uf multi layer for stereo mode
in bridge mode i just change C19 & 20 to 474 mkm
3. change all C 224 in output to mkm 474 since according the data sheet there is no effect with bigger value
4. change all 47uf cap at C5,6,7,16,17,18 to 100uf as recommended by the data sheet (i change this for both mode)
5. and there is power 2 (since its align with main filter i just called it that) i change it to 470n idk what is that for tho
6. at tone control board (only have bass and volume tho) there is no change in value just change the carbon with metal resistor for signal path
after all done and fire-up my speaker & let assume the volume have 10 scale
1 there is small hiss at all scale, hiss getting bigger as the volume turn up (did the change in R 2.2 to jumper at output or is it the R 5.1K to 4.7K at input that cause this ? )
2 at 2 or 3 scale the sound is louder than b4
3 while at scale 1 there is no sound at all
4 the subwoofer sound is much smaller than b4 at max bass <- the sw issue is clear using caps 470nf make the gain smaller so revert back to 100nf
the oroginal diagram more or less like this, its a mess sorry
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The four pins in the middle (4, 5, 12, 13) are suppose to conduct a part of the heat to the PCB copper ground-plane. If that is not sufficient, you can glue a heatsink to the top if the housing with cyanoacrylate (second glue). It will not be an impressively good thermal coupling (15 d.celsius/Watt) and you will most likely not be able to remove it again. Alternatively, use a slow running fan.
Building Audio amp with this chip is totally useless as there is no tab for mounting heatsink since it becomes too much hot to touch after few seconds of use without heatsink. Also, it gives motorboating even after connecting high value filter cap near to the vcc pin
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