Uploaded August 2026 | Updated September 2026, 1 week ago
Welcome to Video Two in our series on the anatomy of a push-pull audio amplifier. In this episode, we’re starting right at the front door of the amplifier: the input network.
At first glance, this section of the schematic may look simple, just a few resistors, capacitors, and an input jack, but these parts play a critical role in determining how the amplifier behaves. The input network helps establish input impedance, blocks unwanted DC voltage, filters noise and radio frequency interference, and prepares the incoming audio signal for the first amplification stage. In many ways, this section sets the foundation for everything that happens downstream.
So, before we dive into voltage gain stages, phase inverters, and output transformers, we need to understand how the signal first enters the amplifier and why these seemingly small components matter so much.
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Video Breakdown:
0:00:00 - Introduction
0:00:37 – The Input Network
0:08:11 – DC Offset
0:11:43 – Coupling Cap C3
0:17:51 – R1 Volume Pot
0:19:12 – R3 Grid Stopper
Welcome to Video Two in our series on the anatomy of a push-pull audio amplifier. In this episode, we’re starting right at the front door of the amplifier: the input network.
At first glance, this section of the schematic may look simple, just a few resistors, capacitors, and an input jack, but these parts play a critical role in determining how the amplifier behaves. The input network helps establish input impedance, blocks unwanted DC voltage, filters noise and radio frequency interference, and prepares the incoming audio signal for the first amplification stage. In many ways, this section sets the foundation for everything that happens downstream.
So, before we dive into voltage gain stages, phase inverters, and output transformers, we need to understand how the signal first enters the amplifier and why these seemingly small components matter so much.
===
Video Breakdown:
0:00:00 - Introduction
0:00:37 – The Input Network
0:08:11 – DC Offset
0:11:43 – Coupling Cap C3
0:17:51 – R1 Volume Pot
0:19:12 – R3 Grid Stopper
