This is an 8 ohm load to test power amplifiers. The goal is to automate THD+N calculations using REW and a big resistor block.
I have been using a pair of 200W, 8ohm, resistors that were sourced from eBay.
This project will move forward in three steps. First, will be a cooling enclosure with a switchable fan and banana jack test points. The second step will add an MCU fan controller with over-heat warning, etc. The third step (stretch goal) will calculate dissipated power using the MCU. I have a 16 bit ADC that I plan to use for the purpose of creating an active power display.
Long term, I may add relays to disconnect the resistors if they overheat.
The case is designed to be 1/2 rack width and generally match the dimensions of a 1/2 rack piece of test equipment, like a multimeter, arb gen, etc. It will be 3d printed.
Rear fan mounted.
Front view. The load fits in the lower chamber. The upper chamber is for the MCU and wiring.
The enclosure is designed in FreeCAD. I'm happy to share the source, if anyone is interested.
This project is about to stall because I will be away for a few months but I will circle back next spring and post further updates.