Radio & Television Magazine 50th Anniversary Edition Headphone Amplifier

Digital Home production post: https://www.mydigit.cn/forum.php?mod=viewthread&tid=149355 For details on the production articles and routes, please see the introduction in the 2008 Issue 9 of "Radio and Television" magazine

Asking is a shame (laughs)

The distortion of the classic op amp + class AB transistor Buffer architecture  depends on the performance of the op amp

Comparing the main changes in the original circuit design:

• All-staff patching: patch components have smaller parasitic parameters, which is beneficial to improving performance
• Supports full-wave and full-bridge rectification: now supports single and double winding transformers, no need to choose a transformer
• Separate the power supply of the operational amplifier and the power stage: Isolate the voltage ripple generated by the large current of the power stage on the power bus, providing a purer power supply for the operational amplifier
• Op amps supporting SMD and direct plug packages: Literally choose one of the two
• Double-sided panels: More and wider ground wires reduce coupled noise

Instructions for use: 1. The screw hole in the middle of the long side is connected to the ground. You can choose to connect the shielding layer or the other four holes of the chassis. There is no electrical connection . 2. The DC005 socket is connected to a single winding AC and cannot work properly when connected to DC . 3. Terminals You can connect single winding AC or double winding AC, but the single winding AC must be connected to the two piles circled on the back of the board, otherwise it will not work properly.

Physical map: