FORTE AUDIO F6

Commentary

Stereo power amplifier with IGBT as output element.

IGBT (Insulated-Gate Bipolar Transistor) is the world's first semiconductor output device applied by Forte for power amplifier applications. It combines the advantages of both bipolar transistor and MOS-FET. By incorporating this device, we have acquired the high input impedance and wide bandwidth unique to MOS-FET, the low output impedance and high current supply capability of bipolar transistor.
By applying this IGBT to a power amplifier, high linearity is obtained without using an overall NFB.

The first stage is a class A design composed of J-FET which operates stably at constant voltage by constant current source bias cascode connection.
In addition, the IGBT of the output stage is stabilized further by flowing a high current bias current which is equivalent to A class even though it is AB class.

The power supply is equipped with a custom-made toroidal transformer.

The circuit construction uses dual mono construction to completely separate the left and right audio circuits from the high-current rectifying bridge diode in the power supply and the large-capacity capacitor.

Equipped with balanced input terminal.

Many gold contacts, metal-coated resistors, and silver mica capacitors are used to further improve sound quality.

Model Rating

Type	Stereo power amplifier
Rated Output (20 Hz ~ 20 kHz)	150W + 150W (8 Ω)
Input impedance	40k Ω (balanced, unbalanced)
Gain	28dB(1kHz)
Distortion factor (at rated output)	Not more than 0.1%
Frequency characteristic	3 Hz to 100 kHz -3dB
Residual noise	300 μ V or less
Damping factor	400
Slew rate	50 V / μ sec
Current supply capability	Continuous 16A Peak : 50A
Protection mechanism	Natural air cooling system Automatic shutdown by detection of internal temperature at overheat
Power consumption	160W
External dimensions	Width 435x Height 175x Depth 255 mm
Weight	13kg