Up for sale, a 1970s Shin-ei Anti-Feedback System AF-17 in near-mint condition and in perfect working order, complete with the original packaging. This rare Japanese-made “Anti-Feedback System” is a six-band parametric EQ designed to, as the name would suggest, mitigate feedback, but the AF-17 also works very well as a filter and a clean, transparent boost.

There are six frequency sliders (125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz), ranging +/- 8dB each, with an A.F. In/Out switch (filter on/off) and a Volume knob that also functions as an on/off switch for the entire unit and enables boost functionality when dialed into the upper ranges. The AF-17 runs on a pair of internal 9V batteries.

There’s barely a mark on the enclosure, the graphics are pristine, and the battery compartment door (and original “Japan” sticker) is present.

The original packaging is included.