I've built DAC with pre-amp and headphone amplifier combo several times which surprisingly sound good. Moreover, this might become more practical unit that act as headphone amplifier and can be also connect to home audio system with the same output from the unit itself.
I made PCM63 DAC with this combo here, long before that, I also made portable TDA1543 DAC combo here. The secret of those combo lies on the current output booster that act as buffer, lowering the output impedance which easily drive any headphone or as a signal output to feed the home audio system.
Especially in this post, I will share my latest upgrade for my previous TDA1543 portable DAC combo that I've built last time. This upgrade resulting to better sound quality.
The theory behind this current booster schematic is using unity-gain op-amp that boost up the current output, yet lowering the output impedance. I often using JRC 4556 op-amp for this application that boost up to 70 mA current output per channel. Parallel the op-amps can improve the current up to 140 mA per channel. Very big power for driving headphone. When connecting high current output to home stereo system, the system get benefit from those high current for better dynamic and less dependable from the cable length and quality.
Other method than using the op-amp like this, I also found LT1110 is built intended for same application, but with higher current output up to 150 mA. This massive output is too much for this kind application, driving a headphone or as audio buffer.
For this portable TDA1543 DAC combo, I stick with using a pair of JRC 4556 op-amps.
As you can see from the photo above, this upgrade is changing all the layout. Only using the same battery, same USB to I2s receiver, same TDA1542 DAC IC, same potentiometer, same casing, same mini jack output.
The capacitors are upgraded using Rubycon Black-gate, Elna Cerafine and Panasonic FC. No joke for those high-quality capacitors are really improving the the sound quality.
This DAC combo is sound so good that probably no one will believe that the sound is actually come from TDA1543 DAC. It is also battery powered DAC which is so quiet. The battery can last for more than 8 hours of music enjoyment or about 6 hours when set the volume to maximum and connecting to home audio system.
When I writing this simple post, I am listening 'S Wonderful, Diana Krall - Live in Paris with this DAC combo.
Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.
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