$420 · Hewlett Packard HP 3582A 2 channel audio spectrum analyzer

Hewlett Packard HP 3582A 2 channel audio spectrum analyzer in good operational and cosmetic condition. It covers up to 25 KHz per channel and can measure signal correlation / response / gain / noise, etc. between 2 stereo channels. The first pic shows a 5 KHz sinewave at 0 db with relative 2nd and 3rd harmonic levels (and 5th). The second pic shows the scale illumination turned down and the 2 pull out quick operational guides. The third pic shows the internal random noise source feeding a filter and the corresponding filter output spectrum with marker readouts. The intensity was turned low, so the marker is hard to see (around 7 KHz), but the display is bright and sharp. The operation / service manual is not supplied, but can be found on line. The reference pull out should get you started. It's old school, but works fine.