A preamplifier for magnetic pickups of record players is shown here.The uA 741 is used as an AC coupled non-inverting amplifier operating on a single supply.The amplifier gain is decided by the feedback components in which C2 controls the low frequency roll-off characteristics while C4 reduces the gain at high frequency end to compensate for the pickup characteristics.R3,R4 and R5 form a voltage divider to give a bias of about half the supply voltage to the non-inverting of uA741.The output at pin6 therefore stands at half the supply voltage.R5 and C3 form a supply line filter to reduce the hum level ans also to eliminate “growling” in case the preamplifier circuit is operated on a common supply with other circuits.
Circuit diagram with Parts list.
Assemble the circuit on a good quality PCB or common board.
Mount the IC1 on an IC base .
The circuit can be powered from a 12V battery or 12V DC power supply.
Up to 24 V DC can be given to power the circuit.I prefer 12 V DC.
Mono sockets can be used to connect the input and output.
Would you better analyze the circuit? The formula shows the frequency dependence of the value of the capacitors C2 and C4. I’d like to know how to calculate a circuit design to pre-am for my subwoofer.
am looking for amplifier for double sub-woofer,2chanel using 12volts
we have magnetic pickups are there,it is frequent failure due to starter hitting. please send alternate solution for that.