My next project, it's a low power version of my 250W amp that I recently made. 250W is a bit of overkill for home use and for normal casual listening hardly 100W max is enough.

So, I removed 2 pairs of output transistors, changed the driver and predriver stage. Lower the supply rails and now we have a decent 100W into 8 ohms amplifier.

I simulated the circuit in Multisim and the results are as follows:

Supply voltage- +/-50V DC

Power Output: 140W into 8 ohms load at clipping, 260W into 4 ohms load at clipping.

Distortion Figures:

THD1- 0.001% THD @ 1kHz 120W into 8 ohms.

THD20- 0.005% THD @ 20kHz 120W into 8 ohms.

Input Sensitivity:

1.6V for 120W into 8 ohms.

Although Multisim is a very conservative simulation software, it's simulation results are very much close to the real world. I have simulated every project that I made and they performed and measured very close to the actual results.

This amplifier would easily do 120W into 8 ohms with +/-50V supply and 160W into 4 ohms with +/-45V supply with the specified output transistors.

+/-60V is really the max supply voltage if you are using an 8 ohm speaker and at this supply voltage a 4 ohm speaker should never be connected, the output transistors would fail driving a 4 ohm load at that supply.

For a 4 ohm load +/-48V is the max supply voltage and of course you would need big heatsinks and fan cooling is advisable.

Designed the PCB in sprint layout and I have integrated the Power supply on the Amplifier board itself. So, in a stereo amp, each amp module would have it's separate Bridge rectifier and filter capacitors for minimum crosstalk between the channels. Of course, independent power transformer is also an option.

Here's the schematic:

PCB:

Regards & Cheers !!!!

Aniket

So, I removed 2 pairs of output transistors, changed the driver and predriver stage. Lower the supply rails and now we have a decent 100W into 8 ohms amplifier.

I simulated the circuit in Multisim and the results are as follows:

Supply voltage- +/-50V DC

Power Output: 140W into 8 ohms load at clipping, 260W into 4 ohms load at clipping.

Distortion Figures:

THD1- 0.001% THD @ 1kHz 120W into 8 ohms.

THD20- 0.005% THD @ 20kHz 120W into 8 ohms.

Input Sensitivity:

1.6V for 120W into 8 ohms.

Although Multisim is a very conservative simulation software, it's simulation results are very much close to the real world. I have simulated every project that I made and they performed and measured very close to the actual results.

This amplifier would easily do 120W into 8 ohms with +/-50V supply and 160W into 4 ohms with +/-45V supply with the specified output transistors.

+/-60V is really the max supply voltage if you are using an 8 ohm speaker and at this supply voltage a 4 ohm speaker should never be connected, the output transistors would fail driving a 4 ohm load at that supply.

For a 4 ohm load +/-48V is the max supply voltage and of course you would need big heatsinks and fan cooling is advisable.

Designed the PCB in sprint layout and I have integrated the Power supply on the Amplifier board itself. So, in a stereo amp, each amp module would have it's separate Bridge rectifier and filter capacitors for minimum crosstalk between the channels. Of course, independent power transformer is also an option.

Here's the schematic:

PCB:

Regards & Cheers !!!!

Aniket

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