This is the long delayed followup to the earlier post about power resistors as dummy loads and the nonlinearities found. After some further experimentation an 8 ohm load was built from four Riedon PF2270 series 2 ohm 200W thin film resistors (to give an 8 ohm load) and a surplus heatsink with fans. With 200W […]
As part of some ongoing work earlier this year I needed to test the performance of a high performance 200W/channel class D amp (more on the amp in some future post). To get accurate SNR and THD+N measurements a low pass filter is needed in front of the measurement system as the high frequency switching […]
Performing some tests on a prototype circuit with an Audio Precision AP515 it was noticed that a particular power resistor showed an unexpectedly high amount of distortion, almost 0.5% THD+N.