MOSFET AMPLIFIER MODULE
The 2 Quality Mosfet assembled Mono modules as presented herewith are based on a standard symmetrical design using 8 gain and driver semiconductors and either 2 or 4 output Mosfet's for loudspeakers with 4 to 16 ohm loads 1.2 volt input required for the full rms output.
Offset voltage less than 20mv(adjustable)-idling current (adjustable) normally biased for class AB at 100ma.. Purists can set idling current for class a operation, heat and power supply will be the deciding factor.
Modules available 120 and 250 watts RMS into a 40ohm load will be less into higher loads.
Modules 120 will supply 40 to 120watts rms @ 40ohms, depending on power supply and heatsink Output
powerwill of course be less as speaker impedeance increase. The 120watt mono audio
module(semiconductors) consist of 8bi polars and 2 power Mosfets 10 diodes and in addition includes on
the same pcb, a power limited cutout plus a mains
switch on delay circuit(absolutely necessary).
a Pos 52v Dc and neg. 52v Dc at 250VA (watt) is required for the 120w mono unit transformer 40v + 40v ac @ 220va and a suitable heatsink.
To change the 120 watt module to a 250 watt unit requires only 2 additional mosfet output devices and will normally need a bigger power supply and heatsink, and currents re adjustments.
a Pos 70 v Dc and neg. 70v Dc at 500VA(watt) is required for the 250w mono unit, it will require a transformer 55v + 55va @ 550va and a suitable heatsink.
Smooothing caps, use at least 10,000mfd 100v for the 250w module and a bridge rectifier of 25amps a smaller VA (Watt) transformer and voltage rating could be used of less rms output, it depends on your requirements.
Offset and idling current set for normal operation, includes the output device heat
coupler, power on delay and power limited. All on the same pcb and very reasonable in
size measuring 140mm x 80mm and 40mm high. You may require some parts as below for
completion.
cool heatsink.