I was just given a used Arturia Mini Brute to mess around with. What basic equipment do I need to amplify/hear the sound produced? I have already purchased headphones. If it is not obvious, I have almost no experience with electronics.
According to the "main features" information at the bottom of https://www.arturia.com/products/hardware-synths/minibrute/overview it has a 1/4" audio output, and a 1/4" headphone output.
Most "consumer quality" headphones have a smaller 3.5mm plug, which is the standard size on cellphones, etc. If that is what you have, you need a "3.5mm socket to 6.35mm jack plug audio stereo adaptor" like this (1/4 inch is the same size as 6.35mm).
These are very widely available, and cheap. As usual, you get what you pay for - the very cheapest ones may not be very durable.
Note, if you buy one by mail order, make sure you are ordering exactly what it says above - you don't want one has a 3.5mm plug and a 1.4" socket, which would let you plug "professional quality" headphones into a cellphone!