DIY Tube Headphone Amplifier with Direct Heating

What is Three Directs? It refers to three key aspects: direct heating of the cathode, direct connection, and direct signal transmission.

· Direct Heating: The filament of a direct-heating tube is the cathode.

· Direct Connection: From the decoder to the headphone amplifier, the signal passes through without any potentiometer. Volume control can be done on the decoder or mobile phone, as the mobile phone can control the player.

· Direct Signal Transmission: There is no coupling capacitor in the signal path.

This is a super simple tube headphone amplifier, yet its sound quality is far from simple—it's a high-quality headphone amplifier.

The casing can be made using a wooden box, similar to the one shown in the image.

Circuit Diagram

Actual Product Image Below

The 3A5 tube is highly sensitive to external interference, but adding shielding eliminates this issue.

The total power consumption of the device is 6.3W.

After testing, this headphone amplifier allows you to enjoy music without worrying about disturbing others.

That's it!