Connecting Multiple Amplifiers To One Source
By Robert Jones · 2020-08-29
Yes, you can run multiple amplifiers from a single source! After 20+ years, I'll show you how to do it right, avoiding buzzing messes and damaged kit, so you get bigger, clearer sound.
It's a question that keeps popping up, whether it's in my email inbox or from lads dropping by the workshop: "Robert, can I run more than one amplifier from a single source?" And my straight answer, without any faffing about, is a resounding yes, you absolutely can. But hold your horses, because it's not just a case of plugging things in willy-nilly. There are a few crucial bits you need to get right, otherwise, you'll end up with a right old mess of buzzing and hums, or even worse, you'll knack your beloved kit. Believe me, I've seen plenty of both over my twenty-odd years tinkering with hi-fi gear.  *Connecting Multiple Amplifiers To One Source — tested in the SpeakersMag workshop. This setup uses a couple of older Arcam P1 power amps and a Rega P9, just for illustration.* **Quick Verdict: Done properly, it's a cracking way to get more out of your system, offering improved dynamics and flexibility.** ### Who it's for: * Anyone with bi-wireable or bi-ampable speakers looking for better sound. * Home cinema enthusiasts needing more power than their AVR can deliver. * Those wanting to run multiple zones or systems from one high-quality source. * DIYers and upgraders keen to experiment and optimise their setup. * Listeners who value clarity, dynamics, and control in their music or films. ### Who should skip it: * People happy with their current single-amp setup and sound. * Anyone looking for a simple, plug-and-play solution without any fuss. * Those on a very tight budget, as it often means buying more gear. * Listeners primarily using basic all-in-one systems. ## Why Even Bother? More Power, More Control, Better Sound Now, you might be sat there wondering why on earth anyone would want to connect multiple amps to one source. Good question, that. There are a fair few solid reasons, depending on what you're trying to achieve with your system. It's not just about bragging rights, honest. It's about getting the best out of your speakers and making your listening experience genuinely better. ### Bi-amping and Tri-amping: A Real Revelation First off, let's talk about bi-amping or tri-amping. If you've got speakers with separate terminals for the bass, mid, and treble drivers – sometimes four terminals for bi-wiring, sometimes six for tri-wiring – you can give each section its own dedicated amplifier. Or, more commonly, a dedicated channel from a multi-channel amplifier. This can really tighten up the sound, giving you noticeably better separation and detail, especially in the bass. Instead of one amplifier trying to drive the whole lot, struggling to control big bass cones while simultaneously reproducing delicate high frequencies, you've got dedicated power for each part of the frequency range. It's like having specialised teams for different jobs, rather than one generalist trying to do everything at once. I've had a few pairs of bi-ampable speakers come through the workshop over the years – B&W 603s, some older Monitor Audios, even a pair of rather lovely PMC FB1s – and when you feed them properly with dedicated power, they just sing. The bass becomes punchier, tighter, with better definition. You can hear individual bass notes rather than just a thud. The mids become clearer, vocals sit more naturally in the soundstage, and the highs just float, with more air and less harshness. It's a revelation, honestly. You hear details in recordings you swear weren't there before. The overall dynamic range just opens up, giving the music more life and impact. It's a bit like taking a blanket off your speakers. ### Home Cinema: When One Amp Just Isn't Enough Then there's home cinema. Oh, the joys of a proper home cinema setup! When you start getting into serious surround sound, especially with Dolby Atmos or DTS:X, a single all-in-one AV receiver often just doesn't cut it. You might need separate multi-channel power amplifiers for your main front speakers, your surrounds, your height channels, and sometimes even dedicated monoblocks for your subwoofers (though subs usually have their own internal amps these days). Trying to squeeze all that power out of one box, especially with demanding speakers in a large room, can leave the sound feeling squashed, thin, and lifeless during those big action sequences. Remember when I helped my mate Dave set up his first proper home cinema in his new garage extension? He'd gone a bit mad, bless him, with huge floorstanders, a couple of active subs, and an upper-mid-range AVR. He was complaining it sounded a bit thin, especially during big action scenes, and the dialogue was getting lost in the mix. We ended up tracking down a couple of older, but very capable, Rotel two-channel power amps on eBay for the front left and right speakers, using the AVR purely as a pre-amplifier. The difference was honestly night and day. Explosions suddenly had genuine impact, you felt the rumble in your chest, and dialogue was crystal clear even during chaotic scenes. It just showed him, and reminded me again, just how much difference proper dedicated power can make. An AVR is a jack-of-all-trades, master of none, in many respects. Separating the pre-amp duties from the power amp duties really allows each component to do its job better. ### Multi-room or Multi-zone Audio: One Source, Many Rooms Another common scenario is running multiple systems in different rooms from one high-quality source. Maybe you've got a fantastic turntable or a high-res streamer in your living room, but you also want to hear that music in the kitchen or the study, perhaps through a different set of speakers and a smaller amp. You don't want to buy a whole new turntable for each room, do you? No. So, you use a distribution method that allows the signal from your primary source to feed multiple amplifiers. I've set this up for a few clients over the years. One chap had a cracking Naim system in his main lounge, but he wanted a simpler, less intrusive setup for his dining room and conservatory. We used the Naim pre-amp's multiple outputs to feed a couple of smaller, more discreet power amps – a decent Yamaha in the dining room and a tiny, almost invisible Topping Class D amp in the conservatory, driving some ceiling speakers. Worked a treat. Everyone got to enjoy his vinyl collection, no matter where they were in the house. ## The Nitty-Gritty: How to Connect Them Up Without a Hitch Right, so you're convinced you need more than one amp. Good stuff. Now for the crucial part: how to actually connect them without causing hums, buzzes, or knackering anything. There are a few main methods, and the best one for you depends entirely on your existing kit and what you're trying to achieve. ### Method 1: Pre-Amplifier with Multiple Outputs (The Best Way) If your pre-amplifier or integrated amplifier (used as a pre-amp) has multiple sets of pre-out connections, you're in luck. This is by far the cleanest and most straightforward way to do it. Many higher-end pre-amps and AV receivers will have a "Main Out" or "Pre Out 1" and a "Pre Out 2" (or Zone 2 Out, or multiple L/R pairs). You simply connect one set of pre-outs to the input of your first power amplifier and the second set of pre-outs to your second power amplifier. Simple as that. The advantage here is that the pre-amp is designed to send a clean, low-level signal to multiple power amps without any signal degradation or impedance matching issues. This is how I set up Dave's home cinema, using the AVR's pre-outs to feed the Rotel power amps. It's clean, robust, and generally causes the fewest headaches. **Pros:** * Cleanest signal path, minimal noise. * Designed for purpose, no impedance issues. * Allows easy volume control from the pre-amp. **Cons:** * Requires a pre-amp or AVR with multiple pre-outs, which not all have. ### Method 2: Y-Splitters / RCA Splitters (Use with Caution) This is where it can get a bit dicey if you're not careful. You can use RCA Y-splitters – those little cables that take one RCA input and split it into two outputs – to send a single source signal to two different amplifiers. You plug the Y-splitter into the source's output, then connect each leg of the Y to an amplifier's input. Now, I've used these myself in a pinch, or for temporary setups. They *can* work. But they can also cause problems. Splitting an analogue signal like this effectively halves the impedance seen by the source, and can sometimes introduce noise or hum, particularly if the amplifiers have different input impedances or ground potentials. You might also find a slight drop in overall signal level, though usually not enough to be a major issue for line-level signals. I remember trying this years ago with an old Marantz CD player feeding two different integrated amps for an A/B comparison. One amp sounded absolutely fine, the other developed a faint hum. Swapped the splitters, still the same. Swapped the amps, and the hum followed the same amp. It wasn't the splitter's fault directly, but the combination of its effect on the source's output and that particular amp's input stage. So, while it's cheap and easy, proceed with caution and listen carefully for any unwanted noise. **Pros:** * Cheap and readily available. * Simple to connect. **Cons:** * Can introduce noise or hum. * May affect impedance matching. * Slight signal level drop possible. * Not recommended for critical listening or permanent setups. ### Method 3: Dedicated Signal Splitter/Distribution Box (The Robust Option) If your pre-amp doesn't have enough outputs and you're wary of Y-splitters, or if you need to feed more than two amplifiers, a dedicated signal splitter or distribution box is your best bet. These devices are specifically designed to take one input signal and distribute it cleanly to multiple outputs, often with buffering or impedance matching built-in to prevent degradation or noise. They typically come with multiple RCA outputs and sometimes balanced XLR options for more professional setups. These can range from simple passive boxes to active powered units. Passive ones are fine for a couple of outputs if well-designed, but active ones are usually preferred for more outputs or longer cable runs, as they can amplify and buffer the signal, ensuring it remains strong and clean. You'd connect your source (or pre-amp output) to the input of the distribution box, then connect each amplifier to an output of the box. I installed one of these for a chap who wanted to run five different zones in his house from his main hi-fi setup – lounge, kitchen, dining room, patio, and garage. A basic Y-splitter setup would have been a buzzing nightmare. We used a powered distribution amplifier, and it worked flawlessly. Clean signal everywhere. **Pros:** * Clean and robust signal distribution. * Prevents impedance issues. * Suitable for multiple amplifiers/zones. * Active units can buffer and boost signals. **Cons:** * Additional cost for the unit. * Another box in your rack (if active, another power cable). ### Method 4: Using an Integrated Amplifier's Pre-Out/Main-In Loop (For Bi-amping) Some integrated amplifiers have a "Pre-Out" and "Main-In" connection, often linked by removable U-shaped jumpers. This loop is usually there for inserting an equalizer or other signal processor, but it can also be used for bi-amping. You'd remove the jumpers, connect the "Pre-Out" from your integrated amp to the inputs of your *second* power amplifier. Your integrated amp then acts as the pre-amp for both itself (driving your main speakers' treble/mid sections) and the second power amp (driving the bass sections of your main speakers). This is a bit more specific to bi-amping and relies on your integrated amp having these connections. It means your integrated amp is providing the pre-amplification for both power stages. Just make sure you understand which amp is driving which part of the speaker – typically the integrated amp's own power stage drives the tweeters/mids, and the external power amp drives the woofers, as woofers generally require more current and power. **Pros:** * Excellent for bi-amping with an existing integrated amp. * Maintains integrated amp's pre-amplification quality. * Relatively straightforward if your amp has the connections. **Cons:** * Specific to integrated amps with pre-out/main-in jumpers. * Doesn't provide multiple independent zones. ## Important Considerations: Don't Mess It Up! Just bunging wires together can lead to tears, or worse, expensive repair bills. Keep these bits in mind: ### Matching Levels and Gain When you're running multiple amps, especially for bi-amping, you need to be mindful of gain. Gain refers to how much an amplifier boosts the incoming signal. If your amplifiers have wildly different gain structures, one part of your speaker (e.g., the treble) might sound much louder than another (e.g., the bass), leading to an unbalanced sound. Some power amps have input level controls, which are a godsend here. If not, you might need to choose amps with similar gain specifications or live with a slightly unbalanced sound profile. It's not usually a deal-breaker for separate systems in different rooms, but it's crucial for bi-amping a single pair of speakers. ### Ground Loops and Hum Ah, the dreaded hum! This is probably the most common issue when connecting multiple pieces of audio equipment. A ground loop occurs when there are multiple paths to ground, creating a small current flow that manifests as an audible hum (usually 50Hz or 60Hz, depending on your mains frequency). If you suddenly get a hum after connecting a second amp, a ground loop is almost certainly the culprit. **How to fix it:** * **One Wall Socket:** Try plugging all your audio components into the same multi-socket extension lead, which is then plugged into a single wall socket. This often helps create a common ground point. * **Ground Loop Isolators:** These are small, inexpensive devices that you can insert into the RCA signal path. They break the ground connection between components while still allowing the audio signal to pass. They can sometimes slightly degrade the signal quality, but often the hum is far more annoying. * **Lift the Ground:** Some equipment has a ground lift switch. Use it with caution and only if you know what you're doing, as proper grounding is important for safety. * **Balanced Connections:** If you have the option, balanced XLR connections are inherently better at rejecting noise and ground loops than unbalanced RCA connections. If your source and amps support them, use them. I've spent countless hours tracking down hums in systems over the years. It's usually a process of elimination: disconnect everything, then add components back one by one until the hum appears. The component you just added, or the cable connecting it, is the clue. ### Cable Quality and Length Don't skimp on your interconnects. Especially when sending signals to multiple amplifiers, decent quality, well-shielded RCA cables are a must. They don't need to be silly money, but avoid the bargain basement, flimsy types. Longer cable runs are more susceptible to picking up interference, so use the shortest practical lengths for your setup. This is particularly true for line-level signals going into power amplifiers. ### Speaker Protection If you're bi-amping or tri-amping, ensure you connect the correct amplifier output to the correct speaker input terminals. Bass amp to bass terminals, treble amp to treble terminals. Accidentally connecting a high-power bass amplifier to your delicate tweeters will likely result in a very sad, very expensive pop. Double-check all connections before powering anything on. A quick visual check is always worth its weight in gold. ## Real-World Examples & Gear Recommendations Let's talk specifics. I've seen all sorts of gear come through SpeakersMag, and here are a few thoughts on what works well for multi-amp setups. ### Pre-amps with Multiple Outs For sheer flexibility, a good dedicated pre-amplifier is hard to beat. Brands like **Audiolab, Rotel, Arcam, Marantz, and Cambridge Audio** often offer models with multiple sets of pre-outs. An **Audiolab 8300CDQ** (around £1200-£1500 new) is a cracking example – it's a CD player, DAC, and pre-amp all in one, with multiple RCA and balanced XLR outputs. Perfect for driving a couple of power amps or an integrated amp for bi-amping. Similarly, higher-end **Denon or Yamaha AV receivers** (say, the Denon X6700H or Yamaha Aventage A8A, both £2000+) will have extensive pre-outs for every channel, making them ideal control centres for a serious home cinema with external power amps. ### Power Amplifiers for Bi-amping If you're bi-amping, you often don't need two identical power amps, especially if one is driving bass and the other mids/treble. For the bass, you want something with good current delivery and a robust power supply. Brands like **Parasound, Rotel, and even older NAD or Quad** power amps are fantastic for this. For the mids and treble, clarity and detail are key. A **Naim NAP 100** (around £500-£700 second hand) or a **Cyrus Mono X** (if you're feeling flush, £1500+ used) could be superb. Don't forget about Class D amplifiers too – some of the smaller **Topping or SMSL** power amps offer incredible performance for the money and can be surprisingly good for driving mids and highs, often with very little noise. You can pick up a decent little Topping PA5 for under £300, and it'll surprise you. ### Distribution Boxes For a simple, passive RCA splitter, something like an **Audioquest G-Y Splitter** (around £20-£30) can work if you're lucky with your gear. For something more robust and active, look at brands like **Pyle, ART, or Behringer** for audio distribution amplifiers. An **ART S8 8-channel splitter** (around £150) offers a lot of flexibility and solid performance without breaking the bank. For really high-end studio-grade solutions, you're looking at brands like **Rupert Neve Designs or Radial Engineering**, but those are serious pro-audio bits for serious money, probably overkill for most home setups. ## Comparison of Connection Methods | Method | Complexity | Cost | Signal Quality | Best For | |:-------------------------|:-------------|:---------------------|:-----------------|:---------------------------------------------| | **Pre-amp Multi-Out** | Low | Varies (pre-amp cost)| Excellent | Bi-amping, multi-room from high-end source | | **Y-Splitters** | Very Low | Very Low | Variable | Quick temporary setups, simple splits | | **Signal Distribution Box** | Medium | Medium | Very Good | Multiple amps, multi-zone audio, noise rejection | | **Integrated Pre-Out** | Medium | Low (existing amp) | Excellent | Bi-amping with an existing integrated amp | ## FAQs: Your Common Questions Answered ### Can I mix and match different brands of amplifiers when connecting to one source? Absolutely, you can! In fact, it's quite common, especially in bi-amping or home cinema setups. The key is to try and match their gain characteristics as closely as possible, especially if they're driving different parts of the same speaker. If they're in different rooms, it's less critical. Just be mindful of potential ground loop issues, which can sometimes be more prevalent with mixed brands. ### Will connecting multiple amplifiers degrade my audio quality? If done correctly, using a pre-amp with multiple dedicated outputs or a quality active distribution box, you should experience no noticeable degradation. In fact, for bi-amping or distributing a high-quality signal to better power amps, the overall *perceived* audio quality will likely improve due to better power delivery and control. Where you *might* see degradation is with cheap passive Y-splitters, which can sometimes affect impedance and introduce noise. ### Do I need special cables for this setup? Not necessarily "special" in the sense of proprietary, but good quality, well-shielded RCA interconnects are a must. Avoid the really cheap, flimsy cables that come free with some gear. For longer runs, consider slightly thicker, better-insulated cables. If your equipment supports it, balanced XLR cables are even better for rejecting noise. ### How do I control the volume if I have multiple power amplifiers? If you're using a pre-amplifier (either a dedicated unit or an AVR acting as one), that will be your master volume control for all connected power amplifiers. If you're using Y-splitters directly from a source like a CD player without a separate pre-amp, then you'd need to control the volume on each individual amplifier, which can be a bit of a faff and lead to unbalanced sound between speakers. That's why a proper pre-amp is usually the preferred method. ### What's the difference between bi-amping and bi-wiring? Ah, a classic question! Bi-wiring uses a single amplifier but runs separate pairs of speaker cables from the amp's output terminals to the bass and treble terminals of a speaker. It's often a subtle improvement, if any, and sometimes more about cable dressing. Bi-amping, on the other hand, uses *two separate amplifier channels* (or two entirely separate amplifiers) to drive the bass and treble sections of a speaker independently. This is a much more significant upgrade, as each amplifier has less work to do, leading to better control, dynamics, and separation. It's proper electrical separation, not just wire separation. ## Final Word So there you have it. Connecting multiple amplifiers to one source isn't some dark art reserved for the boffins in white lab coats. It's a perfectly sensible, and often highly rewarding, way to get more out of your audio setup. Whether you're chasing that last ounce of detail from your bi-ampable speakers, building a monster home cinema, or simply want to share your music collection across different rooms, there's a method that'll suit. Just remember the crucial bits: get your connections right, understand the role of your pre-amp, and be mindful of potential hums. Take your time, do a bit of research on your existing kit, and you'll be enjoying a sound that's bigger, clearer, and more dynamic than you thought possible. It's well worth the effort, trust me. I've seen it time and time again; a bit of extra power and careful signal management can transform a good system into a truly great one. Go on, give it a go. Your ears will thank you for it!