High Quality Low Wattage Amplifier

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To get 2 clean watts (non clipping) from an 8 ohm load, you need no less than 14 or 15 volt supply. If you need 4 to 5 watts, look at ICs rated for around 20 volts (typical use, not max supply voltage). So why not just use an LM1875 or TDA2050? These chips will run just fine at the lowered voltage.

If lower supply voltage is needed, you need a bridge amp.
 
Thank you John, but is driving LM1875 at lower voltage an optimal design? Is there any IC with quality of LM1875 but at lower wattage and lower price?

It is has global negative feed back just like virtually all other power amp ICs. It will sound fine under lower voltage. Output swing is not optimized as much as some lower voltage chips, but it gets you in the power range you wanted.

The beauty of it is, you can adjust the supply voltage to what you need. Say you want more power down the road, you can upgrade to a stronger power supply. Just use components to handle the higher voltage and larger heatsink.

For example, this small monoblock that is based on the TDA2050 will operate on 5 volts to 30 volts and from 30 to 45 volts with a fan. It can produce 27 non clipping watts with a 38 volt supply (4 ohms) or about 7 watts into 8 ohms using a 24 volt power brick from an old HP inkjet printer.
An externally hosted image should be here but it was not working when we last tested it.
 
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