Made this dummy load box to help me organize my bench when testing audio amplifiers. Usually I use a high power resistor mounted on the heath sink connected to amplifier under test with cables and connectors to different test equipment and most of the time it looks messy. With this box test connections should be easy and organized. I used two 4.7Ohm /200W resistors per channel as primary load. They are not inductance free but this will work for my test. Each resistor is adjustable by means of sliding contact.
The single measurement channel consists of switchable load 4 or 8 Ohms and BNC connector to the analyzer or scope. The analyzer part is wired through resistive attenuator 0dB and -20dB as needed during the test. The 20dB attenuator is matched to 600 Ohm load. I did this to use external audio transformer in case amplifier is in differential configuration.
The monitor circuit enables me to listen to audio if needed.
Each measurement channel is floating.