CFB opamp amplifier
The amplifier is equipped with a soft start device (Soft Start), a headphone connection delay (Delay Unit), as well as protection against DC at the output (Protection Unit). The power supply of the amplifier is made according to the classical scheme: a separate secondary winding for each power supply, diodes for each shoulder STTA806D Turboswitch, Jamicon power caps. The amplifier is made on high-speed op amps from Analog Devises.
Chassis coming soon.
Chassis is done.
Next, two amplifier circuits that can be implemented on this chassis. Or any other of your choice. The first scheme is the parallel connection of the AD8016, 5 pieces in each channel. The second circuit is LM1875 or TDA2050 (pin-to-pin compatible). And, further, constructive execution.
A circuit based on 4 optocouplers silonex_nsl-32sr2 (Chinese analogue of vtl5c3) was used as a volume control. Found online as a DIY "Lightspeed" Passive LDR Attenuator. In one photo, two types of optocouplers are shown together for comparison, they differ in size. And they also differ in that the Chinese counterpart has a glow of the LED through the terminals in the case.
I used an ALPS RK09 100k precision variable resistor to adjust the volume. Also seen in the photo.