Absolutely any amplifier is characterized by the maximum signal output power. This is the long-term power that is released at the maximum load of the amplifier. But sometimes the situation requires that the load be higher, and the "stuffing" of the amplifier cannot provide this. Then you have to increase the power of the amplifier.
Instructions
Step 1
Power only the power amplifiers that are in the case using a separate stabilized power supply with appropriate power. Leave the preamplifier power supply from the standard power supply. The voltage of the stabilization unit will be equal to the supply voltage without load. This will be required to approximately double the power for the same load resistance. However, there is a danger that the output transistors will not survive.
Step 2
If the first option does not suit you, power the amplifier from a separate power supply unit with a higher supply voltage in relation to the standard one. Find Shushurin's amplifier circuits on the Internet. Having modernized the details here and there, redo everything to fit his scheme. According to this circuit, the output should be 100 watts.
Step 3
If this is not for you, use the parallel connection of the outputs. This will be the most correct decision, but it will lead to a radical locksmith redevelopment of the amplifier and will require certain skills in electronics from you.
Step 4
In any case, make a separate power supply. It is difficult to cram a 250 W transformer into a standard case, and even more so a 400 W one. Make a switch from external to internal power. Try to put in a toroidal transformer; only this, of course, will already cost more. Also, be sure to improve the cooling of the radiators - install computer fans near the transistors. Do not connect speakers less than 8 ohms.
Step 5
Think about what to do with protection. Coarse or discard only partially! Be sure to set the shutdown function when a constant voltage appears. For a room, for example, 20 square meters, two-channel 25 W will be quite enough, especially considering that the acoustics with normal powerful bass.
