LM1875 PCB, Which To Use

[Mark Whitney]

is there a way to change some of the resistors and to keep the polyester capacitors (or increase them to 4uf - this is possible to fit)
is there online tool where I can check such calculations?

To get any real difference without changing the resistors, you can increase C5/6 to 100uF-220uF. If it will fit, you can use Nichicon Muse UES1E101MPM. What is not clear to me is how high the offset is or how high it will be after replacing the capacitors.

As a test you could short C5/6. Check DC (offset) at the output before connecting speakers. It should not be more than 50mV. This will get the FR under 10Hz.

 

[AndrewT]

thank you for the answers
one more last question
is it good idea to use to electrolitic capacitors to make non polar one
in order to not have difficulties with the capacitor polarity

Using a pair of back to back polar electrolytics to make a Bi-Polar electrolytic works quite well.
The pair passes AC very well and even works for the much more onerous duty of filtering.
For DC blocking duty where you are not filtering the frequencies in the passband, an electrolytic is almost as good as any capacitor type.

Bi-Polars can also be used back to back and tests have shown this to give slightly improved performance in filtering duty, making them almost as good as MKT types.