Friday, November 18, 2011

2 input headphone amplifier with TPA6120

I already designed circuit and 3 versions of PCB with TPA6120. I heard only good reviews about this circuit, this is the reason why I made new version again. In this board I want to use all features of this circuit with 2 inputs and one outputs placed to the PCB, with transformer. I want to use this device for my computer sound-card what is EMU1212m, this card shipped without headphone output (and without microphone input). But have very good sound quality, therefore I need this headphone amp.

Because I would like to use all possible features with all-in-one PCB:
  • Small transformer placed to the PCB, with 2 independent symmetrical +/-15V outputs. This is because separated power possible for left and right channels.
  • 2 inputs on the PCB with volume control and jack or RCA inputs.
  • Master volume and output jack.
  • Mini audio mixer after inputs.
  • After the mixer, unbalanced/balanced converter.
With this board I can use the features of TPA6120.

The new schematic:

The transformer and the voltage regulators placed to the PCB, with two independent outputs with 4 regulator devices. With inputs, you can choose what you like, 2 pcs 6 .3mm jack, or stereo RCA. Maybe 1 jack and 1 RCA. The balanced converter make better quality and more volume.

This is the PCB:

The longer side of PCB is about 15cm. Around the inputs have something "chaos". You can choose between RCA and Jack inputs this is the reason why 2 footprints on one place, but the inputs have to be placed to the bottom side (must be soldered on the top) and the volume potentiometers placed to the top layer (must be soldered on the bottom). But I think this is no problem on assembly. Because the transformer is on the board, 230V must be connected to the header called "Conn2". The regulators on the edge of the board can be screw to the wall of case or to heatsink. 3 "power filter" circuits required as module for this board, one for mixer, 1-1 for left/right unbalanced/balanced converter.

See also:

PCB sales of this project
Module name Size
PDF SCH PCB image Tested Price (US$)
Des. Sim.1 Full2 Sim.1 Full2 Man3
2 input headphone amplifier
90x160 144 Yes
Yes Yes - - No 21
31 Ask
How to order? Please read the rules carefully!

No comments:

Post a Comment