Above is an image of the "dead bug" version of the schematic at the top of the Zithromax vs generic page. The heat sinks on the right are two TO-3 heat sinks with the transistors inside and facing one another. The "E" and "B" pins are shown on the outside of the heat sinks. |
Close up images of the discrete audio amplifier from the 160 Meter Receiver in the Solid State Design book from ARRL. The LM301 IC is shown mounted upside down wired "dead bug" style. |
The input is at the bottom left at the phone connector. The cable comes from the product detector. The output of the pre-amps is at the top of the capacitor (negative side) at the top right of the image. The picture shows two pre-audio amplifiers. A PC mount volume control was added to the first amplifier to adjust the output of the first pre-amp to match the various IF/product detector circuits that I have been using over the years. The second amplifier is a two transistor direct-coupled audio amplifier. The direct-coupled amplifier comes from the Progressive Communications Receiver. In the Progressive Communications Receiver, the audio is muted by grounding the emitter of Q2, which would be simpler than wiring in a the relay. The white wire (at the two phono connectors at the top of the image) connects the output of the first pre-amp to the input of the second pre-amp. |