Lightspeed Passive Attenuator using Silonex NSL-32SR2 Optocouplers
I remember when taking electronics in college it was mentioned that you could order standard transistors, or you could order matched transistor pairs for high end audio use. A pair of transistors that were matched would work in perfect unison since even devices out of the same batch will have some slight variations. Have a look at the image below for an example of testing a ton of devices