STK4141II based comercial reciever

[Daniel(Del)]

Dear Friends,

I've been reading some parts of this forum for a long time, and this is my first post.

I am Brazilian, and therefore, sorry for the english...

I have a Gradiente(tradicional Brazilian factory) reciever, based on the STK4141II chip. I know that this is a problem for modding this amp, but as I've read here a lot of projects here using the STK series and I am not good in projecting, I came here to ask for help, and to know if it is possible to improve the sound quality and/or power...

I attach a copy of the diagram(power and supply stage) and the amp specs:
50w RMS per channel, 8 ohms load, THD 0,1%
56w RMS per channel, 4 ohms load, THD 0,1%
Load impedance: from 4 to 16 ohms
Harmonic Distorcion, 1kHz, 8ohmd, maximum power, 0,1%

I use this system only with 8 ohms speakers, which support 80w RMS.

Thanks for the attention,

Daniel.