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The LM3886 is rated to deliver 68W RMS to a 4 ohm load when it has a positive 28VDC and a negative 28VDC supply. The total supply voltage is 56VDC and the sine-wave output is 16.5V RMS which is 46.6V peak-to-peak. So it has a loss of 56V- 46.6V= 9.4VDC.
It is rated to deliver 38W RMS to an 8 ohm load when it has a positive 28VDC and a negative 28VDC supply. Again the total supply voltage is 56VDC. The sine-wave output is 17.4V RMS which is 49.3V peak-to-peak.
So its loss is reduced to 56V-49.3V= 6.7VDC because the current is lower.
It gets very hot when its output is 68W. Any higher output would fry it even if it has a huge heatsink with a fan.
What is your "32V"? Is it 32V peak-to-peak across 4 ohms? Then the power is only 32W RMS.
Look in Google for The Gain Clone Amplifier. It is made with the LM3886 and LM3875 power amps. One guy makes and sells a stereo amp for $4000.00US!
The datasheet spec's a max operating supply of 84V and graphs show output clipping with a 6V loss. The distortion is rated when the output p-p voltage is 16V less than the total supply voltage. Then the power with an 80V supply is calculated at 68W.Can we increase the supply voltage so that we get 68W output while the load is 8 ohms?
The datasheet says that for +-35V supply the said IC gives 50W of power for a 8 ohms load. So how about the possibility of increasing the supply voltage so that we get 68W out of chip whiteout damaging it?
Gain has nothing to do with the max output voltage at clipping. Its distortion is spec'd when its output p-p voltage is 14V less than ther supply voltage.The other question regarding your above calculations for 4 & 8 ohms load at 56V supply is that what are the suitable maximum of p-p and RMS voltages for input of the said chip while its gain is 21 ( i.e the input voltages which do not cause the chip to go to saturation yet let the chip to work decently)? is the response 2.2 Vp-p and 0.78 Vrms for the 4 ohms case and 2.34 Vp-p and 0.82 Vrms for the 8 ohms case?
The datasheet spec's a max operating supply of 84V and graphs show output clipping with a 6V loss. The distortion is rated when the output p-p voltage is 16V less than the total supply voltage. Then the power with an 80V supply is calculated at 68W.
The "spike protection" might be activated making it sound awful. It will also get very hot.
Gain has nothing to do with the max output voltage at clipping. Its distortion is spec'd when its output p-p voltage is 14V less than ther supply voltage.
And of course it delivers a power of 66.7 for a load of 4 ohms.With a gain of 21 then an input of 2.2V p-p produces an output of only 46.2V which is 33.4W into 8 ohms. A supply of 60V will do it at low distortion.
Your 2.2V p-p input and a gain of 21 causes the output power to be 68W into 4 ohms.
The datasheet shows graphs of distortion. With a plus and minus 28V supply and a 4 ohm load the distortion is very low up to an output of typically 68W.First Are you agreed with me that by a supply voltage of +-28V and a load impedance of 4 ohms, The output power of the LM3886 is 68W?
If so, Please consider that +-28V means 56V total supply,. the peak to peak voltage across the 4 ohms load at 68W output power as I calculated in my previous post is 46.64V (Vp-p = 2 x 1.414(sqrt P x R) = 46.64V).
It reflects that by having a 56V supply voltage the the P-P output voltage which you can expect is 46.64V, So the lose is:
56V - 46.64V = 9.36V.
So by 56V supply voltage you will not get any voltage larger than 46.64V in the output, So that output voltage is the reference voltage for calculating the clipping/ going to saturation state. for instance by a gain of 21 the MAXIMUM P-P input voltage must be 46.64/21 = 2.2. any higher p-p input voltage larger than 2.2V causes the output to go to saturation, Right? Unless you say That the chip is able to provide more power than 68W by a supply volatge of +-28V?!
The datasheet for the TDA2030A shows a circuit with an output of only 12W or 16W into 8 ohms and its distortion can be as high as a horrible 0.5%. It has enough power output to blast your house only if you have rice-paper walls. Most home stereos in North America have at least 100W per channel at very low distortion.I had built a 5.1 amplifier using TDA2030A ic which has excellent sound clarity and enough power output to blast my house, i think u should also Try TDA2030A