When you are using a phone without a headphone jack, the possibility of getting lossless audio quality is almost impossible. The only solution is a portable AMP DAC with the size of a dongle. These little gadgets may not seem to be much, but they are jam-packed with technology and provide a superior audio experience than basic headphones. Moreover, you can build a cheap portable DAC/amp all by yourself.
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Building a Portable AMP DAC
We’re going to build a modest do-it-yourself headphone amplifier. It is not the simplest project conceivable since it was developed with a focus on size and performance. The best portable DAC/amp should have a maximum output current of 90 mA at 7 volts RMS.
- Required Tools
- Soldering iron
- Solder paste
- Tweezers (non-magnetic).
- Loupe or microscope
- Rubbing alcohol
Other than these, you will need a few micro F capacitors and small resistances. Get a good-quality USB connector, power switch, and two operational amplifiers.
Placing the Components
To get your job easy, you should mount all the ICs first in the metal box to make the best portable headphone amp. After that, you need to tackle all the big components one by one.
Because the connection is the most challenging aspect of the project, it’s an excellent place to begin. Apply some solder paste to the pads, or if using solder wire, pre-tin the pads with the least amount of solder feasible.
After carefully mounting the power connection, I’ll begin with the gain stage since it is the pivotal component on the board and contains the most features. The gain stage boosts the signal. Additionally, it filters out noise from the signal that might cause the device to malfunction, such as the radio frequencies.
You should begin by positioning the operational amplifier, ensuring that it is oriented correctly. While drag soldering is often the simplest way for ICs, the pin pitch of these op-amps is big enough that soldering one pin at a time is simple.
The buffer stage takes the gain stage’s enhanced signal and feeds it to the headphones. In essence, it is a gain-zero amplifier. As a result, it cannot give voltage gain, but it may generate a current gain. This is particularly critical when utilizing low-impedance headphones.
Each channel certainly has a buffer stage consisting of two parallel op-amps. Due to the parallel operation of the op-amps, the amplifier can generate more current to the headphones than a mono op-amp can.
Power and Power Switch
After completing the signal route, it’s time to tackle the power part. You should begin with the indication LED [D1] and the resistor that is a limiting resistor. In my experience, LEDs with a nominal current of 20 mA are typically much too bright.
Finally, there is the power switch. This should be installed last since it is a through-hole component, and the legs may cause the board to wobble after installation.
Images: iFi Audio
Slava is a man of mystery and no-one seems to know exactly where he is at any point in time. When he isn't enjoying writing about all things audio and technical he can be found researching his next project of interest. The man never rests.
This post was last updated on 2022-12-11 / Some images from Amazon Product API & some links may be affiliate links which may earn us a commission from purchases.