4 input headphone amplifier with TPA6120 chip

I already have schematic and PCB design with TPA6120 chip with 2 inputs. Now I made same design but with 4 inputs and one line output. The new design contains PCB transformer, dual +/- 15V power supply, 4 channel mixer without preamplifiers, unbalanced/balanced converters, and line output with level adjustment.

The schematic:


The device contains 4 audio inputs with volume adjustment. The input connector must be soldered to the bottom of PCB (blue) and the volume must be potentiometers soldered to the top (yellow) of PCB. The input and line output connectors can be 6.3mm jack OR stereo RCA connector. The headphone output can be 6.3mm jack only. The PCB contains header for 4 power filter circuits (whats are optional if not required) for 4 dual operational amplifiers. The operational amplifier chips are compatible with TL072 for cheapest solution, NE5532 for better quality, and with LT1124 for the best quality. These chips used for the input mixer, for unbalanced/balanced converters, and for the line output amplifiers.

The PCB design:


See also:

• More unbalanced to balanced converters
• Simulation of unbalanced-balanced converter
• 2 input headphone amplifier
• Headphone amplifier with TPA6120
  

PCB sales of this project Module name Size (mm) Area (cm2) PDF SCH PCB image Tested Price (US$) Des. Sim.1 Full2 Sim.1 Full2 Man3 4 input headphone amplifier 189x112 212 No Yes Yes - - No 30 39 Ask How to order? Please read the rules carefully!