How To Split RCA For Multiple Amps
By Robert Jones · 2020-08-23
You can split RCA and connect multiple amps with it. The procedure
Right, so you're thinking about splitting an RCA output to feed a couple of amplifiers. It's a pretty common query I get, especially from folks tinkering with their car audio or even those trying to get a bit more oomph in their home cinema setup without buying a new head unit or preamp. Now, before we dig in, let's be clear: we're talking about splitting an *unbalanced* RCA signal here. If you're dealing with balanced XLR or similar, it's a different ball game entirely. For most home and car audio stuff, though, RCA is the standard. ### Why Split RCA? Good Question! Honestly, there are a few reasons why you might want to do this. Maybe you've got a two-channel head unit in your car, but you want to run a separate amplifier for a subwoofer and another for your front speakers. Or perhaps you're adding a second subwoofer to your home cinema and your AV receiver only has one sub out. I've been in both those situations myself. Back in the day, I had an old Ford Fiesta with a rather basic head unit. Wanted to add a sub, but didn't want to fork out for a fancy new stereo. A simple RCA splitter was the answer there. Worked a treat, it did. ### The Simple Way: Passive RCA Splitters The most straightforward way to split an RCA signal is with a passive Y-splitter cable. You've probably seen them kicking around. One male RCA plug goes into your source (your head unit, preamp, whatever), and it splits out into two female RCA jacks, ready for your amp cables. **Pros:** * Dead simple to use * Cheap as chips * No power needed **Cons:** * Can introduce signal loss, especially with longer cable runs * Potential for noise interference (hum, hiss) * Impedance matching can be an issue with some gear I generally recommend these for shorter runs and when your source unit has a decent output voltage. If you're dealing with a really long cable run – say, from the front of a vehicle to an amp in the boot – you might start noticing a drop in signal quality. I've seen it happen. Sounds a bit flat, loses some dynamic range. ### The Better Way: Active Line Drivers/Splitters Now, if you want to do it properly and avoid potential headaches, an active line driver or distribution amplifier is the way to go. These little boxes take your single RCA input, amplify it, and then split it out to multiple outputs. **Pros:** * Maintains signal strength (no loss) * Reduces the chance of noise * Better impedance matching * Often offer gain control for each output **Cons:** * More expensive than a passive splitter * Requires a power source (usually 12V for car audio) * Another box to find space for I've used countless active line drivers over the years, both in cars and in my home workshop. For anything critical, they're worth the extra cost. For instance, I rigged up a multi-zone audio system in my workshop a while back, running different amps to different areas. An active line driver was essential to keep the signal strong and clean everywhere. If you're serious about your sound, don't skimp here. ### Wiring it All Up Regardless of whether you go passive or active, the wiring is pretty similar: 1. **Identify your source:** This is where your RCA signal *starts*. Could be a head unit, a standalone preamp, an AV receiver, etc. 2. **Connect the splitter:** Plug your single male RCA from your source into the input of your splitter (or line driver). 3. **Run cables to your amps:** From the outputs of your splitter, run individual RCA cables to the inputs of each of your amplifiers. 4. **Power (if active):** If you're using an active line driver, you'll need to connect it to a power source. For car audio, that's usually 12V from the battery, with a remote turn-on wire from your head unit. For home audio, it'll be a wall wart or similar. 5. **Grounding:** This is key, especially in car audio. Make sure all your components, including your splitter/line driver and amps, have a good, solid ground connection. Poor grounding is a recipe for annoying hums and buzzes. Trust me on this, I've spent far too many hours chasing down ground loops. ### What About Impedance? A Quick Chat Impedance matching is something that often gets overlooked, but it's important. When you split a signal passively, you're effectively asking the source to