Bass Amplifier made from cheap Aura InteractorAmplifier

This is my Firs Instrucion, so the next ones will be better ;-)
I have bought an Cheap (5Euros) AuraInteractorAmplifier from a german Shop
http://www.pollin.de/shop/shop.php?cf=detail.php&pg=NQ==&a=NTk4OTYzOTk=
It delivers approx. 16W RMS.
The Powesupply primary is 220V...240V at 50Hz.
They wrote you cold use it as Subwoofer Amplifier, but when I tried it, the sound was horrible.
So I modded it with good results.
Sorry, not much fotos since i have lost the data cable for my mobile phone :-(

step 1Overview Here is the original plan before my changes. You see a lot of things needed for a buttkicker, but not for a (Sub)woofer driver, like the flipflops U3 and the multiplexer U4… step 2Things needed you will need Tools: a cross screwdriver to open the box and get the electronics out . a soldering iron suitable for electronics, i used a 15W with a needletip a file… step 3Ripoff unused parts Unscrew the black screw in the center to get the circuit board off. Cut off the legs of U3 and U4 and desolder the rest of the legs from the circuit board. U3 and U4 is p… step 4Change the copling caps next you desolder the coupling caps C7, C10, C20. then fit in the replacement caps for replacement of C10 and C20 use values between 470nF and 2200nF at 16V or bigger volta… step 5The Low pass Fiter Now we can change the cutoff frequency of the low pass filter around U2d, since 2kHz is much too high for a subwoofer. The filter is a sallen-key-lowpass of 2nd order. I d… step 6modify frequency response of the power stage this is done very easy, you only have to desolder and extract C9 to get the lower frequencies better amplified. step 7Youre done now put the board into the case, screw all together again. thats it. To use it connect a woofer (4Ohm gives most power) via the cynch (RCA phono) plug. be sure the speaker… ------------------------------------------------------------------------------------------- image not found out:{ top: 0.10069444444444445, left: 0.186, width: 0.152, height: 0.2361111111111111, text:"volume control\n" } multiplexer U4 gets ripped off hubi flipflop U3 gets ripped off hubi Powesupply connector hubi audio input connector earphone plug hubi speaker connector hubi mode switches hubi volume control hubi this one is out of function after modification hubi this screw holds the board hubi Power indicator LED hubi overload indicator flashes when the amplifier is overdriven. hubi i