Ever wondered what everything does on the back of a professional DJ mixer? What plugs in where? Why there are so many different kinds of sockets? You’re in the right place.
Understanding mixer connections helps you work with any DJ gear, in any venue – controllers, CDJs, all of it. Professional mixers contain pretty much every type of connection you’ll encounter on DJ equipment, so once you understand how a pro mixer works, you can confidently handle any set-up. More importantly, this knowledge means you won’t come unstuck when asked to plug something in or troubleshoot at a gig.
Understanding your inputs
Professional mixers typically have four channels on the back, numbered 1-4, corresponding to the channel controls on the front. Each channel has multiple RCA sockets – you’d think you only need two (left and right for stereo), but there’s actually four because they serve different purposes: phono and line inputs.
Phono inputs are for turntables. Record decks have very low electrical output, so mixers need to amplify the signal significantly. The circuitry doing this is called a phono preamp, and its quality greatly affects how records sound. High-end mixers have excellent phono preamps, while budget mixers often cut corners here.
Line inputs are for everything else – CDJs, controllers, or any equipment that’s already amplified. Plug equipment into the wrong input and you’ll either barely hear it or it’ll distort badly. Some mixers only have one set of RCA inputs per channel with a switch to toggle between phono and line mode.
You’ll also find earth poles next to the phono inputs – these are metal posts where you attach the earth lead from turntables. This eliminates background noise, hum, and buzz, so if a turntable sounds terrible with crackle, check the earth lead is properly attached.
Microphone inputs typically use omni-sockets accepting both jack and XLR connections, so you can plug in any microphone type. Digital inputs offer an alternative to analogue RCA connections, carrying everything down one cable while keeping the signal path cleaner for better sound quality.
Understanding your outputs
Master outputs send your mixed audio to the sound system using different connection types. RCA outputs work perfectly for shorter cable runs when speakers are nearby. XLR outputs use balanced connections that maintain signal quality over long distances – essential in clubs where PA systems are far from DJ booths.
High-end mixers sometimes include record outputs that capture signal before the master volume control. Throughout a night, you might adjust the master volume between DJs or as venues fill up. Record outputs provide consistent levels regardless of these adjustments, so your shared recordings don’t have volume fluctuations throughout.
Booth outputs provide separate connections for DJ booth speakers with independent volume controls. Once club volume is set, you can adjust booth monitoring to help with transitions, then turn it down to chat or protect your hearing.
Effects, networking, and other connections
Professional mixers include send and return connections for external effects processors. Send outputs route audio to effects units, which return the processed signal back to the mixer. Pro DJ effects units (like the RMX-Ignite) require send and return connections to work as intended – without them, you can’t use professional effects boxes the way they’re designed.
Read this next: DJ Mixer Basics – Everything Beginners Should Know
Ethernet connections (Pro DJ Link) network your mixer with CDJs and provide internet connectivity. This enables BPM synchronisation between players, music sharing from USB drives across all units, and tight integration between effects and beat grids.These network connections are becoming increasingly important as modern DJ set-ups access cloud-based music libraries and streaming services directly through the mixer.
USB connections let you use professional mixer set-ups as high-quality DJ controllers. You’ll find both USB-B and USB-C options, often with separate inputs allowing multiple computer connections.
And finallly, headphone outputs are designed with both quarter-inch and eighth-inch sockets, which means you can plug in any pair without needing to carry adapters (something DJs used to forget all the time).
The Bigger Picture
Understanding mixer connections is foundational gear knowledge for any DJ. At Digital DJ Tips, we teach DJing through five essential areas: gear, music, mixing, performing, and success.
Gear knowledge ensures you won’t struggle with unfamiliar equipment at venues, but it’s just the start – you also need to know how to find and organise your music, develop mixing skills that work across any equipment, and perform confidently for audiences.
Want to learn all five steps? Our book Rock The Dancefloor! is free to download. And if you’re ready to master everything from gear setup to mixing and production, grabbing an All Access Pass gives you lifetime access to every course we offer.
