What is Pre-Out on AV Receiver and When to Use it?-the best Guide
By Robert Jones · 2022-04-25
Right then, let's chat about pre-outs on AV receivers. I've seen countless setups over the years, and understanding these connections can truly lift your sound from good to brilliant. It's not just tech speak, it's about getting the best from your gear.
Right then, let's talk about something that crops up a fair bit when folks are putting together their home cinema or hi-fi systems: the humble "pre-out" on your AV receiver. Sounds a bit techy, doesn't it? But honestly, understanding what it does and when to use it can be the difference between a decent setup and one that truly sings. I've had countless customers and mates down the pub asking me about these connectors. "Robert, do I need to use the pre-outs?" "What even *are* they?" "My old amp didn't have 'em, why's this new one got a load?" All valid questions. And after more than two decades tinkering with speakers, amps, and everything in between, I've seen all sorts of setups – good, bad, and downright baffling. **Quick Verdict:** A pre-out transforms your AV receiver into a versatile hub, offering better sound and future upgrades. ### Who it's for: * Anyone wanting to upgrade their power amplification for clearer, more dynamic sound. * Folks with hungry, low-sensitivity speakers that demand more grunt. * Home cinema enthusiasts looking to separate their amplification for each channel. * If you plan to add a dedicated subwoofer and want precise control. * Anyone who fancies running a multi-room audio system from their main receiver. * If you're after a more audiophile-grade sound from your home cinema setup. ### Who should skip it: * Those with entry-level or budget AV receivers that don't have pre-outs (obviously). * Anyone happy with the sound from their current receiver's internal amplifiers. * If your speakers are easy to drive and don't need loads of power. * If you're on a very tight budget and every penny counts towards speakers or sources. * Folks who prefer simplicity and don't want extra boxes or cables.  *What is Pre-Out on AV Receiver and When to Use it?-the best Guide — tested in the SpeakersMag workshop.* ## What Exactly *Is* a Pre-Out on an AV Receiver? Alright, let's strip it back to basics. Imagine your AV receiver is a brain and a brawn unit rolled into one. The brain bit is the "pre-amp" section – it handles all the inputs, volume control, signal processing (like surround sound decoding), and tone adjustments. It takes all those tiny, delicate signals from your Blu-ray player, streaming box, or turntable and gets them ready. The brawn bit is the "power amp" section, which takes those ready signals and boosts them up to a level that can actually drive your speakers. A "pre-out" (short for pre-amplifier output) is simply a way of tapping into that signal *after* the brain has done its job, but *before* it hits the brawn. It's an RCA connector, usually, that sends out a line-level signal – a clean, unprocessed audio signal that's been volume-controlled and shaped by your receiver's pre-amp section. But critically, it hasn't been amplified to speaker level yet. Think of it as an intermediary step. Instead of the signal going straight from the receiver's brain to its own muscles (internal power amps), the pre-out lets you send that signal to *external* muscles – a separate power amplifier or an active subwoofer. It's a bit like giving a detailed instruction to an external team instead of doing the heavy lifting yourself. Most modern AV receivers, especially those mid-range and higher, will have at least one set of pre-outs for a subwoofer. Many decent ones will have pre-outs for the front left and right channels, and the really good ones will have full 7.1 or even 11.2 pre-outs, meaning every channel gets its own dedicated line-level output. ### Why Bother with Pre-Outs? Good question! For years, your bog-standard integrated amplifier or receiver did everything in one box. And for many, that's perfectly fine. But as sound quality improved and systems got more complex, the limitations of cramming everything into one chassis became apparent. 1. **More Power, Better Control:** The most common reason people use pre-outs is to connect a more powerful, higher-quality external power amplifier. The internal amplifiers in AV receivers, while often decent, are usually limited by cost, space, and heat. A dedicated power amp typically has a much beefier power supply, better components, and can deliver more clean, undistorted power. This means your speakers will have more headroom, sound clearer at higher volumes, and have better control over the drivers, especially in the bass. *Anecdote:* I remember a chap in Bristol who had a Denon X3600H – lovely receiver, but he was struggling to get his big, hungry KEF Q950s to really sing. He added an Emotiva BasX A-500 power amp, connecting it via the front left and right pre-outs. The difference? Night and day. The KEFs woke up, the bass tightened, and the soundstage opened right up. He was chuffed to bits. 2. **Improved Sound Quality:** By separating the pre-amp and power amp sections, you can often reduce interference and noise. Power amplifiers draw a lot of current and generate heat, which can sometimes affect the delicate pre-amp signals if they're in the same box. Plus, a dedicated power amp usually means higher quality components throughout, leading to a cleaner, more refined sound. 3. **Future-Proofing and Upgradability:** This is a big one. If you've got a cracking AV receiver with all the latest processing tech – new HDMI standards, Dolby Atmos, DTS:X – but its internal amps are starting to feel a bit weak, pre-outs mean you don't have to ditch the whole receiver. You can just upgrade your power amps, bit by bit if you like, keeping your receiver for its processing capabilities. It saves money in the long run if you're serious about your sound. 4. **Dedicated Subwoofer Control:** Nearly all receivers with pre-outs will have one for the subwoofer. This isn't just any old line output; it's specifically designed to send a low-frequency effects (LFE) signal to your active subwoofer. It also lets your receiver apply crossover settings, so your main speakers aren't trying to reproduce bass frequencies they're not good at, leaving the heavy lifting to the sub. Essential for proper bass management. 5. **Bi-Amping Options:** If your speakers support bi-amping (meaning they have separate terminals for the high and low frequencies), and your receiver has pre-outs for all the channels, you can use two external power amps (or a multi-channel amp) to drive your speakers. This can offer even greater control and clarity, though it's a bit more advanced. ## When to Use Them: Practical Scenarios So, you've got these mysterious pre-outs. When should you actually plug something into them? Here are the most common and beneficial situations: ### 1. Adding a Stereo Power Amplifier for Front Speakers This is probably the most popular use. You've got a decent AV receiver, but you want your main stereo music listening to be a bit more robust. Or perhaps your front speakers are a bit power-hungry. Connect the Front L/R pre-outs to a good quality stereo power amplifier, and then connect your front speakers to that external amp. Your receiver still handles the source selection, volume, and surround processing, but the external amp provides the muscle. *My tip:* If you're only going to upgrade one part of your amplification, start with the front left and right. That's where most of your music and a huge chunk of your movie sound comes from. ### 2. Using a Multi-Channel Power Amplifier for Home Cinema For serious home cinema buffs, a dedicated multi-channel power amplifier is the way to go. You'd connect all the pre-outs from your AV receiver (Front L/R, Centre, Surrounds, Surround Back, Height channels – whatever you have) to the corresponding inputs on a 5-channel, 7-channel, or even 11-channel power amp. This completely bypasses your receiver's internal amps, letting it act purely as a pre-processor and source switcher. You'll often notice a significant improvement in dynamics, clarity, and the ability to drive all channels simultaneously without breaking a sweat. ### 3. Integrating an Active Subwoofer This is pretty much standard practice these days. You'll find a dedicated "Subwoofer Out" or "LFE Out" pre-out on almost all AV receivers. You simply run an RCA cable from this output to the LFE input on your active subwoofer. Your receiver then manages the bass, sending only the low frequencies to the sub, and handling the crossover points between your main speakers and the sub. Crucial for a balanced and impactful home cinema experience. ### 4. Setting up a Zone 2 (Multi-Room Audio) Some receivers have "Zone 2 Pre-Outs." These let you send a separate audio signal to another room, controlled independently. You'd connect these pre-outs to a separate amplifier in the second room, which then drives speakers in that zone. Handy for having music in the kitchen while someone else is watching a film in the living room. ### 5. Using an External Headphone Amplifier (Less Common) While not strictly a "pre-out" in the traditional sense, some higher-end receivers might offer a variable line-out that you could feed into a dedicated headphone amplifier. This is rare though, as most receivers have perfectly capable headphone jacks built-in. But if you've got a seriously expensive pair of cans and a top-tier external headphone amp, it's an option. ## What to Look Out For When Using Pre-Outs It's not quite as simple as just plugging things in and hoping for the best. A few things to keep in mind: * **Matching Components:** Try to match the impedance and sensitivity of your speakers to the power output of your external amplifier. It's not an exact science, but don't try to drive massive, inefficient speakers with a dinky little amp. Likewise, don't blast super-sensitive speakers with an industrial power amp unless you know what you're doing. * **Cables Matter:** For pre-out connections, you're dealing with delicate line-level signals. Good quality RCA interconnects are important. You don't need to spend a fortune, but avoid the really cheap, flimsy ones. They can be prone to interference and signal degradation. I've seen plenty of buzzing and hums caused by poor quality interconnects over the years. * **Calibration:** Once you connect an external amp or subwoofer, you *must* re-run your receiver's automatic calibration system (like Audyssey, YPAO, MCACC, Dirac Live, etc.). This ensures all channels are correctly level-matched, distances are set, and room correction is applied properly. Don't skip this step! * **Receiver Internal Amps:** When you use pre-outs for a specific channel, the receiver's internal amplifier for that channel is usually bypassed. This is what you want. However, if you *only* use, say, the front L/R pre-outs, the receiver's internal amps for the centre, surrounds, etc., will still be active. This means the power supply for the receiver is still working hard, even if not all its internal amps are being used. ## Comparing an AV Receiver's Internal Amps vs. External Power Amps Let's be honest, most people just use the internal amps. And for many, they're perfectly adequate. But for those chasing that extra bit of performance, an external amp, connected via pre-outs, is often the answer. | Feature | AV Receiver Internal Amplifiers | External Power Amplifier (via Pre-Outs) | | :---------------- | :-------------------------------------------------- | :-------------------------------------------------- | | **Convenience** | All-in-one box, simpler setup | More boxes, more cables, slightly more complex | | **Power Output** | Often limited, especially when driving all channels | Higher, more stable power, better dynamic headroom | | **Sound Quality** | Good for most, can struggle with demanding speakers | Generally superior, clearer, more detailed sound | | **Heat/Noise** | More susceptible to heat and electrical noise | Separated from pre-amp, less noise/interference | | **Upgrade Path** | Limited, requires full receiver replacement | Modular, allows gradual upgrades | | **Cost** | Included with receiver, lower initial outlay | Additional purchase, higher overall system cost | | **Footprint** | Single component | Multiple components, takes up more space | As you can see, it's a trade-off. Convenience and cost versus outright performance and flexibility. For someone just starting out, or with a smaller room and easier-to-drive speakers, the internal amps are often fine. But once you start looking at larger speakers, bigger rooms, or just demanding more from your system, the external amp route becomes very appealing. ## Frequently Asked Questions About Pre-Outs ### Q1: Do I *need* an external amplifier if my AV receiver has pre-outs? No, you don't *need* one. The pre-outs are there as an *option* for upgrading your sound. Your receiver's internal amplifiers will work just fine on their own. Think of them as an expansion port. ### Q2: Can I use different brands of AV receiver and power amplifier together? Absolutely! In fact, it's very common. As long as both components have standard RCA connections for the pre-outs/inputs, they should be compatible. You might even find that mixing and matching can give you a unique sonic signature that you prefer. ### Q3: Will using pre-outs improve my sound immediately? It depends. If your current receiver is struggling to drive your speakers, or if you invest in a significantly better quality external amplifier, then yes, the improvement can be immediate and noticeable. If your speakers are easy to drive and your receiver's internal amps are already quite good, the difference might be more subtle, but still there if you listen carefully. ### Q4: My receiver only has a subwoofer pre-out. Can I still connect a stereo amplifier? No, not directly to drive your main speakers. A subwoofer pre-out is specifically for low-frequency signals. If your receiver only has a sub pre-out, you can only use an external amplifier for your subwoofer. To add an external amp for your front speakers, you'd need dedicated front L/R pre-outs. ### Q5: Is it better to buy an AV receiver with pre-outs or a separate pre-processor and power amp combo? That's the age-old question! A separate pre-processor and power amp setup (often called separates) is generally considered the pinnacle for performance, as each component is designed for a single, specialised task without compromise. However, it's significantly more expensive and involves more boxes and cables. An AV receiver with pre-outs offers a fantastic compromise: excellent processing in one box, with the option to upgrade the power side later. For most people, a good receiver with pre-outs is the sweet spot between performance, cost, and convenience. ## Final Word So there you have it, the lowdown on pre-outs. They're not just some fancy connection for geeks; they're a really useful feature that gives you flexibility, upgrade options, and crucially, the potential for genuinely better sound. Whether you're trying to get more grunt out of some hungry floorstanders, or just want a cleaner, more dynamic home cinema experience, those little RCA sockets can make a world of difference. Don't be afraid of them. If your receiver has them, and you're looking to wring a bit more performance out of your system, connecting an external power amp or a beefier subwoofer is often the next logical step. You might be surprised at what your existing speakers are truly capable of once they're fed properly. Give it a go – your ears will thank you for it!