The amplifier has a very pleasant sound in the mid-eighties was patented. Since then, the element base has Since then, the element base has changed quite a lot and it has been possible to simplify the circuit, preserving the idea itself and getting the best characteristics without compromising reliability. The circuit has a preliminary buffer voltage amplifier made on the TL op amp and a two-stage push-pull power amplifier. Both amplifiers are covered by their local negative feedbacks: RR9 and RR
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This Hi-Fi amplifier circuit is suitable for a lot applications like general purpose amplifier, guitar amplifier, keyboard amplifier. The amplifier can be also used as a sub woofer amplifier but a subwoofer filter stage has to be added before the input stage.
The amplifier has a low distortion of 0. Circuit diagram. Capacitor C8 is the input DC decoupling capacitor which blocks DC voltage if any from the input source. IF unblocked, this DC voltage will alter the bias setting s of the succeeding stages.
Resistor R20 limits the input current to Q1 C7 bypasses any high frequency noise from the input. Transistor Q1 and Q2 forms the input differential pair and the constant current source circuit built around Q9 and Q10 sources 1mA. Preset R1 is used for adjusting the voltage at the output of the amplifier. Resistors R3 and R2 sets the gain of the amplifier. The second differential stage is formed by transistors Q3 and Q6 while transistors Q4 and Q5 forms a current mirror which makes the second differential pair to drain an identical current.
This is done in order to improve linearity and gain. Power amplification stage based on Q7 and Q8 which operates in the class AB mode. Preset R8 can be used for adjusting the quiescent current of the amplifier.
The network comprising of capacitor C3 and resistor R19 improves high frequency stability and prevents the chance of oscillation. F1 and F2 are safety fuses. Circuit setup. Set R1 at midpoint before powering up and then adjust it slowly in order to get a minimum voltage less than 50mV0 at the output.
Now adjust R8 so that the multimeter reads Assemble the circuit on a good quality PCB. Before connecting the speaker, check the zero signal output voltage of the amplifier and in any case it should not be higher than 50mV.
If it is higher than 50mV, check the circuit for any error. Replacing Q1, Q2 with another set could also solve the problem. Both Q7 and Q8 must be isolated from the heat sink using mica sheets. R10 and R11 are 5W wire wound type while R19 is a 3W wire wound type.
If 6A ampere bridge is not available, then make one using four 6A6 diodes. C10 and C11 are high frequency bypass capacitors. Filter capacitors C8 and C9 must be at least uF, higher the value lesser the ripple.
IRFP 9240 PDF
Any suggestions on where the error could be located? F1 and F2 are safety fuses. Technical Details Instead I would like you to use separate filters and rectifier for each amplifier, you mount bridge rectifier and filter capacitors of the value shown in each circuit board. Hi Harry can be used. Get fast, free shipping with Amazon Prime. This amp will work, but you have to add a filter circuit at the input. You may also like: I will make a pbc for this circuit if u want it just ask, but has anyone considered using Irfp for this circuit instead?
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