Anyone that wants a Fully working proffessional LM3886 & LM3876 Design here it is.
Tip.1 the chip amp at pin 7 does not have a DC ground. it is an Analog Ground pin which goes to the DAC or input signal ground
The chip amp simply does not need or use any DC ground at alllllllll....
Tip.2 if you use at the Input the 1UF Cap high quality, then you will not get any noises from the input wires or any interference at the inputs
Tip.3 Make sure you have the Grounds separated... with a 2.7 ohm resistor between DC Ground planes and Analog Grounds as shown in the design...
Tip.4 Also as i have said before... Use a GOOD speaker about 500 WAT with a nice BIG magnet... this will increase the Speaker Response time and give you the FULL benefit of the 50Wat chip which has extremely wide BANDWIDTH...
Tip.5 Do not increase the Gain resistor to more than 20K in this circuit it will give you a 20 x Gain. and DO NOT go lower than 15K. Lower Gains means MORE BANDWIDTH and higher gains means LESS bandwidth but higher output power.
Tip.6 The less the Bandwidth the more Voltage one can use. this means if you power the amp at +/-35V DC you should set the Gain at no less than 20K. if you want more sound detail then set it at 15K the gain, and use +/-28V DC and you should have a nicer sound.
Do not think that if you use a +/-28V this will decrease the sound by much if you use the right Speakers. believe me when i tell you , you wont be able to stand in front of it at +/-28V-DC if you have a good speaker of 500Wat with a huge magnet. your chest will be pounded by a hammer at 2 meters away.
PS. in the design at the output i have a 0.1 Ohm resistor which should be ignored as it is used for parallel designs. However for the best output performance with LONG speaker cables to the speakers i strongly suggest to use a 10K resistor in the output with a 0.4 coated copper wire with a 10 turn over the resistor with the ends connected to the resistor, and make sure it is ANTI CLOCK WISE from the OUTPUT of the chip...
The reason it is used is because the LONG cables become CAPACITORS due to long distances and can destroy the AMP in a split second if the capacity on the cables reverse
so the resistor becomes a BLOCKING PROTECTION to such output SURGES... before one should consider using this resistor one must make sure that the cables are more than 10 meters from output of the amp to the speaker...
i highly recommend this amp and this design to anybody that wants to have only but the BEST.
Best to you all and i hope you will enjoy it.