1-piece led meter soft-touch-controls subwoofer rarest graphic equalizer musicsearch hifi japan-only fm presets Diatone Y-500
The Diatone Y500 Cassette Compo (made by Mitsubishi) is one of the rarest boomboxes. Well, it's not really a boombox, because it's not portable.....It cannot accept batteries. It's AC only. The voltage is 100V, and the FM tuner only goes from 76 to 90Mhz, so we're assuming it was sold in Japan only. The entire chassis and speaker panel is made of pressed-wood (MDF). There are 5 speakers (and all of them are active). They are mounted from the outside of the boombox, instead of from the inside like most boomboxes are designed. The center woofer has its own sealed enclosure.
I have never heard one, but knowing Diatone's reputation, I bet it sounds great. The one pictured below is owned by Ebay user cha-valen. You can see there's a lot of controls on it, including music search, Dolby, Echo, FM wireless mic, Stereo Wide, Phono, Aux, and preset stations. It also has a 5-band EQ with its first slider labeled "Dynamic Bass".