Pioneer J-7 Disco Robo

One of the most unique, interesting, and LOUDEST boomboxes from the 80s is the Pioneer J-7 Multi Music Machine, also more commonly known as the Disco Robo.

The Disco Robo name is perfectly suited for this unit, for it does in fact look sort of like a Robo(t)? (Think R2D2). Then there is Disco... this unit is perfect for disco parties. It is extremely loud, being powered by 4 high powered speakers in swiveling housings. 109db is prominently and proudly displayed on the lower corner of the right speaker, and I didn't measure but can confirm that when cranked up, you can hear the audio from any corner and floor of my 2900 sq ft home. It has an electronically actuated tape deck that is simple, yet very reliable and gets the job done, an FM radio that is nothing fancy, just a knob to change stations. The Disco Robo also has very robust mixing features. The 5-linear slide controls on the top panel looks like an equalizer but in fact, are mixing slide bars, allowing you to mix in the following sources: Mic1, Mic2/guitar, echo, tuner and pitch control. The large orange knob is also the volume control or mix control for tape and line-in RCAs. It is also extremely well built.

Sound wise: This set sounds suprisingly good for an audio device that doesn't have sound shaping controls (bass/treble, etc). I'm sure that if an equalizer could be added, it would be very welcome. Normally, I like to play with and adjust tone controls to tailor the sound to my liking and perhaps compensate for the usual lack of bass or treble. Still, even without sound shaping controls, I was happy to find the sound to be extremely well balanced and tone controls not particularly missed. If I were to adjust the sound, it would probably sound like the Disco Robo sounds as-is. The swiveling speakers are a nice touch, and in a Disco/party environment, you would want the sound to travel as far as possible, in multiple directions. As mentioned previously, I found that when the volume is turned up loud, I can move to any room in my 2-floor home and still hear nothing but the music from the Disco Robo, and the home is almost 3000 sq ft. The speakers themselves are full range units and there is no tweeter, nor does it need tweeters, because it has no trouble reproducing crystal clear highs. This may not be the best system to play in a whisper, but when you want volume, then this may be the set you'd want in your music arsenal.

The amplifier is comprised of 2x dual LA4440 Sanyo chips for a total of 4 amplifiers. Each of the channels on each module is run in BTL (bridge tied load) configuration, and I estimate power output to be 20-25 wpc rms.

Problems: Even though the Disco Robo is extremely well built, there are 2 concerns that affect virtually every unit. #1 is the top cassette control buttoms/switches. The controls are designed using good quality switches but housed below a cheap membrane like you would expect to find on a microwave oven. This is unfortunate because most every orginal example I've seen has a degraded panel with many showing total deterioration. A properly designed button system would have been better and last much longer. The 2nd concern is that the woofers have foam surrounds that like the buttom membranes, almost always degraded or simply "gone." They aren't particularly difficult to refoam, but does require a lot of work since the unit will need to be disassembled quite a ways to get to that point. The speakers are extremely heavy with huge (for it's size) magnets, and due to the high power of the amplifiers, do need to be able to handle quite a bit of power.

Cassette control membrane solutions: An owner of one of these units (Superduper) decided to create a solution with solid buttons housed inside a retainer panel. Instead of a plastic membrane, this solution results in 4 discrete nylon buttons. This setup can be purchased and 3D printed at Replacement Disco Robo buttons:

Rarity: It is believed that this model is extremely rare anywhere in the world and especially in the USA. It seems to be more common in Asia and in Australia. They are seldom offered for sale but it is worth looking out for since when sold, they are frequently miscategorized which could cause prices to be lower than they otherwise might be. Still, if you can find one in the USA, go for it. The shipping charges alone to import one from Asia or down under could run well into the hundreds of $$ so keep that in mind when pricing the unit.