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Amplifier Actrk400 ACTRK600 circuit Mosfet IRFP460 600W. The article discusses two amplifier models, one at 400 watts and the other at 600 watts, that are designed to deliver high power output. The Actrk400 amplifier utilizes 6 n-channel Mosfet transistors at the output and produces around 400 watts at 4 ohms. In comparison, the Actrk600 amplifier employs 12 n-channel Mosfet transistors and delivers over 600 watts at 4 ohms.
The ACTRK600 is a power amplifier that uses 12 N-channel MOSFETs (IRFP460) and is known for its robust performance. Here are some key details:
Power Output: It can deliver around 600W at 4 ohms.
Voltage Supply: -60 to -90V DC, dual supply. Usually +-75V
Schematic Amplifier Actrk400 ACTRK600 circuit Mosfet IRFP460 600W
T4 must be mounted on the main heatsink as close as possible to the output FETs.
T6, T7 and T8 dissipate about 3 watts of heat in total and must be mounted on a heatsink
T9. T11 etc = between 3 and 6 IRFP450 or similar, depending on power required.
T10, T12 etc = between 3 and 6 IRFP450 or similar, depending on power required.
Under no circumstances should you turn on this amplifier without checking for errors and assembly, turn it on through a light bulb or resistor to avoid burning something. Make sure the power supply is fully functional and meets the necessary parameters. Check if the power supply provides the required voltage and current. Another point is that to start the amplifier, you do not need to solder all pairs of output transistors, solder only part of them, if the start is successful, you can solder the rest. Using a multimeter, set the resistance of VR2 to the maximum resistance. Correctly connect the grounding, positive and negative power terminals. Temporarily remove the fuses and replace them with 5 watt resistors at 100 ohms. And you can start slowly.
Final Set up And Adjustment
Do not attempt to set up or test a power amplifier module that is not properly mounted on a heatsink. Ensure that the main power supply is fused and that the work area is free of any obstructions. Before proceeding, check all of your work and confirm that the output devices are insulated from the heatsink. The setup should be conducted without connecting an input or load to the power amplifier.
- Check the power supply is operating correctly and verify the rail voltages. Switch the power supply off and check with a multimeter that the rail capacitors have discharged.
- Using a multimeter measure the resistance of VR2 and set it for maximum resistance.
- Correctly connect the ground lead, the two positive leads plus the negative lead to the power amp module.
- Remove the PCB fuses and replace with 100 ohm 5 watt resistors. Connect a multimeter that is set to the 20 volt scale across the positive rail 100 ohm resistor.
- Â Check that the power supply connections are correct one last time and switch on. If the multimeter reading goes off-scale, turn off immediately and find the problem. Check also the 100 ohm 5 watt resistors; they may have gone open cct.
- If everything seems ok adjust VR2 to set the output stage bias current, by measuring the voltage across the positive rail resistor. Adjust for a reading of 4 volts per output FET pair. I.e. For a 6 FET board set for a voltage of 12 volts. This equates to a bias current of 40mA per FET pair or 120 mA total. For the 12 FET board set for a voltage of 24 volts.
- If everything seems ok, check the output offset voltage and adjust VR1 to achieve an offset of less than 10 mV. You will need to wait briefly between adjustments for the offset to settle.
- All being well switch off, back off the bias control trimmer (VR2) and replace the 100 ohm resistors with 10 ohm 1 watt resistors. Switch on again and re-adjust VR2 to get 0.4 volts per FET pair.
- Switch off, remove the resistors and put the fuses back in. Switch on, re-check the offset voltage and adjust with VR1 if necessary.
- The amp module is ready, connect the input and output and enjoy.
BOM circuit Amplifier Actrk400 ACTRK600 Mosfet IRFP460 600W
| Parts | Value | Description | Quantity |
|---|---|---|---|
| Resistors | |||
| R1,R11 | 1K | 1/4W resistor | 2 |
| R2,R15 | 10 | 1/4W resistor | 2 |
| R3,R13 | 33K | 1/4W resistor | 2 |
| R4,R9 | 3.3K | 1/4W resistor | 2 |
| R5,R10 | 220 | 1/4W resistor | 2 |
| R6 | 33 | 1/4W resistor | 1 |
| R7,R12,R14 | 27K | 1/4W resistor | 3 |
| R8,R17,R19,R20 | 330 | 1/4W resistor | 4 |
| R16,R18 | 22 | 1/4W resistor | 2 |
| R21 | 3.3K | 2W resistor | 1 |
| R22,R23,R24,R25,R26,R27, R28,R29,R30,R31,R43,R44 |
27 | 1/4W resistor | 12 |
| R32,R33,R34,R35,R36,R37, R38,R39,R40,R41,R45,R46 |
0.33 | Cement Resistor 5W | 12 |
| VR1 | 1K (102) | 3296W trimpot | 1 |
| VR2 | 50 (500) | 3296W trimpot | 1 |
| Capacitors | |||
| C1 | 1uF (105) | Film capacitor | 1 |
| C2,C5 | 330pF (331) | Ceramic Capacitor | 2 |
| C3,C4,C11,C12,C14 | 100nF (104) 250V | Ceramic Capacitor | 6 |
| C6 | 100uF/25V | Electrolytic capacitor | 1 |
| C7 | 22pF | Ceramic Capacitor | 1 |
| C9,C8 | 39pF | Ceramic Capacitor | 2 |
| C10 | 47uF/160V | Electrolytic capacitor | 1 |
| C13 | 100nF (104) 100V | Film capacitor | |
| C15,C16 | 470uF/200V | Electrolytic capacitor | 2 |
| Semiconductors | |||
| D1,D2,D3,D4,D5 | 1N4148 | DO-35 Switching Diode | 5 |
| D6,D7 | DZ8.2 | 8.2V DO-41G Zener Diode | 2 |
| U1 | +80V | Quick connect Cold-pressed Terminal | 1 |
| U2 | -80V | Quick connect Cold-pressed Terminal | 1 |
| U3,U5 | GND | Quick connect Cold-pressed Terminal | 2 |
| U6 | OUT | Quick connect Cold-pressed Terminal | 1 |
| U7 | +90V | Quick connect Cold-pressed Terminal | 1 |
| Q5 | BC327 | PNP TO-92 Bipolar transistor | 1 |
| Q1,Q3 | 2SC1845 | NPN TO-92-3 Bipolar transistor | 2 |
| Q2,Q4 | BC546 | NPN TO-92-3 Bipolar transistor | 2 |
| Q8,Q7,Q6 | MJE350 | PNP TO-225-3 Bipolar transistor | 3 |
| Q16,Q14,Q13,Q19,Q11,Q15, Q9,Q20,Q17,Q18,Q12,Q10 |
IRFP460PBF | N-Channel TO-247AC-3 MOSFET | 12 |
| Miscellaneous | |||
| F1,F2 | Fuse 10A | Fuseholder + 10A fuse | 2 |
| LR1 | 4uH+4.7 | ZOBEL NETWORK COIL | 1 |
| H1 | IN | 1x2P ,P=2.54mm Pin Header | 1 |
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