In the 1970s the DJ scene was WAY less saturated: For one there was no EDM or electronic music out yet [I'd say the 80's is when that type of music even remotely started]. But with that being said, there was still a good chunk of gear-heads and some DJ's still drooled over certain setups, like the one depicted below. Just like nowadays on the scene, back in the 70's companies attempted to compile various setups into one multi-faced piece of gear. The ‘Squire Stateline' was one of few “DJ consoles” that started the trends of today, bringing together two turntables, a tape player, and an on-console mixer.
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Watch the consoles in action: