Picking the best amplifier can be a pretty hairy procedure - and it gets hairier when you have to consider whether to choose an integrated amp, or a preamp and power amp combo. It's hard enough to do when you know what's going on. If you're new to the audio game, or are moving from headphones to speakers, it can be pretty intimidating. Fortunately, the difference is pretty easy to see - and we're not only going to explain it in simple, straightforward language, we're going to give you everything you need to pick the right amp. So: let's go.
- What Exactly Is An Amp?
- Integrated Vs Pre Vs Power Amps - What's The Difference?
- What Do I Need To Know To Choose One?
- Impedance Matching
- Getting The Most Out Of Your Amp
- Cheat Sheet
- Three Great Amps You Can Buy Right Now
- Video Breakdown
First off, let’s start with the simple bits - the amplifier is the component of your soundsystem that not only powers your speakers, but lets you select the sound source and raise and lower the volume. In it's simplest form - the stereo amp - it handles two channels, the left and the right, both of which make up the audio you here. You can apply anything in this guide to amplifiers in general, which come in a rainbow of colors and types, but we're going to focus on stereo amps for simplicity.
Of course, most amps handle passive speakers - speakers which receive their power from the amp itself. You wouldn’t and you shouldn’t need to connect an amp to active speakers. These are also known as powered speakers, because each of them would already have an internal amp connected and matched to the driver (internal speaker). Similarly, if you are already using a powered A/V receiver, you wouldn’t need an external amp. Every rule has an exception, though, and for the instances where you might be looking to expand an existing system, you could actually hook an additional amp and speakers. '
Yeah, we know. We’ll explain all this below.
To understand the differences between these two amplifier types, and the pros and cons of each, we are going to need to start with what preamps and power amps are. Don't worry – this will make sense in a minute.
Together, a preamp and a power amp take the raw signal from your sound source, which is at a level too low for you to hear, and amplify it, making it loud enough to listen to and imbuing it with some good qualities, like richness and depth.
In more detail: the preamp not only handles the input selection for you, choosing which sound to take from what source, but then cleanly boosts the audio to a stage where the power amplifier can take over, using all its power to get the sound to acceptable levels. They almost always come as two separate pieces of equipment - two big black boxes. Or usually black, anyway. Amp designers aren’t all that imaginative when it comes to design.
Think of this like a good hotel. The preamp is the person behind the reception desk, checking you in. They find out who you are, where you come from, and which room you need to go to. If they are good at their job, they also make the experience a pleasure (in our metaphor, this is the preamp boosting the sound signal just a little). Then, the porter – a guy with muscles enough to handle your bags – takes you up to your room. That’s the power amp. The room, in this case, is your ears.
Now, you can get individual preamps and power amps, and mix-and-match them – a good example would be the Yamaha Aventage MX-A5000 power amp with the Yamaha Aventage CX-A5100 preamp. Those are two fantastic (albeit expensive) pieces of audio equipment that, together, make up your amplification system.
So where do integrated amps come into all this? Simply put, an integrated amp is a box that contains a built-in preamp and power amp. It does all of the above, without needing two separate pieces of equipment and all their attendant wires and remotes. Integrated amps and pre/power combos do exactly the same things, just in different forms. Most affordable stereo amps these days are integrated, and they are by far the easiest solution when you're looking to choose a nap. A perfect example is the Peachtree Audio nova300 (full review here) – don't be put off if you can't afford that one, as there are plenty of other good ones for a fraction of the cost.
So what are the pros and cons of each? Very obviously, integrated amplifiers are the easiest solution here – they use a single box for all your amplification needs, and as a result, are usually cheaper. The downside – and this is where separate pre-and power amplifiers have a significant advantage – is that you can’t upgrade individual elements of the signal chain.
If you want to experiment with mixing and matching different amplifier types from different manufacturers, you’re going to need separate pre- and power amps. If that kind of mixing and matching appeals to you, then it’s probably a significant advantage. However, be warned that this almost always a more expensive solution - these components ain’t cheap!
There’s also this idea that individual amp components always sound better than integrated amplifiers. We call bull on that. These days, integrated amplifiers can sound absolutely fantastic, and although they don’t offer the customization that separate solutions do, they are almost always better for most people.
Choosing a new amp would probably start with just an idea - something like: right, this is gonna be for my living room, I‘ve got a couple of speakers here, and I'm going to be using them movies/music/videogames/whatever.
There are a couple of things that are obviously quite important here. How many speakers do you have? Do you have a subwoofer? What is your sound source? USB from your laptop? A turntable? A media server? Once you know what's going in and coming out of your amp, you can work out how many features you need, without having to spend money on the ones you don't.
That's important, because amplifier prices can escalate quickly. If all you need is a single box to drive a set of mid-level speakers, then you can probably get away with nothing more than a set of inputs and a volume control. If you've got more demanding speakers, then you may need a slightly pricier amp to get the best out of them. The price also goes up if you want more than two channels, such as an additional subwoofer output.
It doesn't help that manufacturers tend to throw a hell of a lot of jargon into the mix, hoping to dazzle you. When in doubt, come check back on this site. We are here to highlight the things you really need to know about.
One of those things is how to match an amplifier with a pair of speakers, in terms of making sure that the power the amplifier puts out is able to be taken up by the speakers and used in an effective way. Their driver size, the power handling and the number of speakers you’d be using are the hard facts which would determine the main specs of your power amp - namely, wattage and impedance (don’t freak out - we’ll go into these in a little more detail below). Once you know these necessary spec figures, you could then sort the contenders by price to match your wallet.
For the majority of people, the easiest way of getting a decent hi-fi system is still to purchase a system-in-a-box (as in: an amp with separate speakers, all in one package) since everything is pre-configured and pretty much ready to play. But: opting for a stand-alone stereo amp would make a lot of sense if you are just amplifying your phone or PC/Mac, or a turntable. And to make sure you have an amp that can drive your speakers to their fullest potential - which, after all, is what this is all about - you're going to need to match them. That, really, is the most important thing.
The amp should be able to deliver, without a struggle, what the speakers can handle at their optimal state of performance - in other words, when they are loud as hell. Audio signals are essentially like waves, and the high point, or the peak, is the crucial bit in terms of how audio signals affect amps and speakers. The loudest sections of a song should not present a problem - for neither the speakers, nor the amp.
If they do (and let’s start with the speakers), it would be when the amp is pushing audio ‘peaks’ well above the handling capacity of a speaker, and…well, let’s just say you will hear it. It sounds like a tearing, flapping distortion noise. This can result in blown speakers, even after a short while. So yeah - don’t do it.
The second scenario of amp/speakers mismatch would be when the loudest audio peaks challenge the amp instead. This would be in the case of the amp being underpowered for the connected speakers, and the problem will manifest itself in signal clipping - the level light indicators (every amp has them) clipping into the red, basically saying: “That’s it, you’ve pushed me too hard, I can’t really handle that, can’t feed those speakers with the level you’re asking me to…oh God, I’m dying, send help.”
This would lead to the amp heating up until it goes bang. Neither blown speakers nor blown amps are a nice thing to experience, and it’s not particularly safe either.
We have a full guide to just this, if you're interested, but it comes down to the following simple rule: You need to find out your speakers' continuous or RMS power (the power they put out at a 'normal' volume) and their peak or dynamic power (the loudest they can go). Then you need to pick an amp that can handle both. You'll be able find these stats on the spec sheet for any given amp or set of speakers.
We mention and describe the term impedance quite possibly in every TMS piece - whether it’s about headphones or speakers. It describes drivability - how easily a piece of gear handles and responds to an electrical signal. Possibly the most confusing fact about impedance is that unlike wattage, the lower the impedance figure, the more optimal power you get out of the equipment.
Impedance is a bit like how a garden hose delivers water to the far end. A constant flow of water would result in a different spraying power, depending whether you have a narrower or a wider hose. A much wider hose would give you less pressure, and a thinner one would be sending out a powerful, high-pressure spray.
Just like with wattage, you’d need to match your speakers’ impedance to that of the amp, and luckily, most hifi-grade speakers and amps are designed to easily match. Any matching you do has to happen at the same impedance - which is important, as speakers and amps often give power figures for different impedances
It’s (slightly) more complex than that, but only slightly. Let us just stress that if your speakers have a really low impedance, they shouldn’t be connected to an amp with a higher one. The other way is generally OK (low amp impedance, high speaker impedance) but in this case you’d be using only a fraction of the amp’s full potential. This is because impedance is directly linked to wattage - in the real world, an amp that pushes 400 watts at 2 ohms (Ω) would be able to push only half that - 200 watts at 4 ohms. It would be halved yet again - down to a 100 watts if connected to a 8 ohm speaker.
Here’s an example. If you have a stereo amp pushing 200W at 4 ohms, you can actually connect it to a pair of speakers running at, say, 25W/8 ohms each. But you’d be utilising only a fraction of the amp’s power. To get the full 200 watts working, you could in fact add another pair of 8 ohm speakers as a ‘daisy chain’, e.g connected to the speaker outlets of the first pair of speakers. In this way, each side (or channel) of the amp would be feeding two speakers running at 8 ohms each and this would be equal to running a 4 ohm speaker on each amp’s side.
This approach is often used in bars and commercial installations, where more spread and room coverage is needed. Choosing a low-impedance amp would allow stringing 2 and sometimes 3 speakers one after another on the same amp channel…but hey, this is something you probably don’t have to worry about.
The example our writer Derrick Lilly gives in the above-mentioned guide is as follows. "If you need 100 watts out of your amp at 8 ohms, pump it into an 8-ohm speaker that can handle 200 watts of Continuous Power. This should give you plenty of headroom for when the impedance drops, causing those Dynamic Power peaks, and a little more room to spread those gooey peanut butter vibes."
And we do love gooey peanut butter vibes...
There’s another scenario, which is if you have a preamp. Preamps, as their name suggests, come before the amp acting as ‘hubs’ for all of your audio sources, allowing you to switch between them at will. Think of a DJ Mixer, which may have many different sources (turntables, a laptop) plugged into it.
They also ensure that the levels fed to the input section of the power amp are optimal and correct - neither too hot, nor too quiet. If using a preamp, the way to connect it would be by sending the left and right outputs of the device into the left and right inputs of your power amp and bingo, you’re set.
Preamps can come in many guises, such as dedicated hifi preamp, a (non-powered) A/V Receiver, or, as we said, a DJ or line mixer.
First things first: setting your levels correctly. The maximum volume you should take it to should be roughly three quarters on the dial, or roughly 3 o’clock (assuming that your amp’s max dial level is roughly around 5 o’clock). The amp will be pushing plenty of clean, continuous power to the speakers and the remaining one quarter of power is left for handling the highest-volume peaks of the material. This is how pros set up amps and not only in home set ups, but for big event installations as well, using 6000 watt beasts. It really works.
You’ll know when a system has hit the sweet spot - you’ll have no distortion, and everything will sound crystal clear at any listening level. This is quite easily achieved with bundled packages - the ‘home theater in a box’ type or similar - and it's a real thrill when you handle it yourself.
Wattage: The power rating and capacity of amps and speakers.
RMS Power. The wattage measure of continuous power that an amplifier can output, or a speaker can handle.
Peak Power: Normally referring to speakers, if their continuous (RMS power) handling is 100 watts, their Peak Power handling is typically four times that- 400 watts.
dB: Decibels. A measure of loudness
Impedance: A value for signal resistance. With high impedance, when only a small current is allowed through and vice versa
Ohm(Ω): The unit of measuring impedance (electrical resistance)
To avoid flooding you with different options, we’ve chosen two of each type of amp – and further, separated each of those two picks into an expensive option, and a budget option. We don’t have roundups of the best pre-and power amps of this year available yet – but we are working on them, and for the time being, you can check out our list of the best integrated amps if you need more info.
We’ve said it before, and we’ll say it again: this is the best integrated amp available right now. It offers an absolutely stunning sound and power, coupled with landmark versatility. It may be the last amp you ever need to buy.
From our review: “Yes, it’s expensive, but so is the latest iPad or MacBook Pro. And unlike Apple products, the nova300 hasn’t tacked on an extra grand because of the brand-name…despite a couple of design hitches, the functionality and feature set it offers is just staggering. Even if it didn’t sound as good as it did, that would still make it worthwhile in our books.”
The cute-as-a-button Sprout comes from a terrific audio marque. Doesn’t have a huge amount of power, but the small setups, it works really well.
Plus, the sound is just superb: rich and full, with absolutely terrific dynamics. Even sometime after release, this remains one of our favourites.
When it comes to power amplifiers, this is the biz: a twelve- channel monster with a monolithic front end and some serious power. Pumping 170 watts per channel into 8 ohms, you’re not going to have any trouble driving your speakers here.
The sound it puts out is unbelievable, too, although we do think it needs to be paired with a good preamp. Still, we doubt you’ll have any trouble choosing one if you stick to the guidelines here.
Is the amplifier above a little bit of overkill? Don’t need twelve channels? Step right this way: we’ve got just the amp for you.
The Niles SI-2150 is a solid, affordable two-channel model from a brand with an excellent reputation. The slim, compact design offers a lot of power and good usability, along with excellent sound. No, it’s not going to trouble the big boys, but it will certainly get the job done.
We’re just saying. Since you’re going to be buying that MX-A5000 power amp anyway, you may as well spend a little bit more – okay, double – and pair it with the perfect preamp.
That would be the CX-A5100, an 11.2-channel whizbang of an amp with remote, Bluetooth, WiFi and superlative sound. Together, these two Yamahas will make some very, very good noise.
This 2.1 channel pre may be getting a little bit old now (it’s from 2013) but that just means it’s undergone a couple of friendly price drops, meaning you can have one of the best preamps on the market for under $700.
It offers pretty much everything you need for a basic setup, including a high quality DAC (digital-to-analogue converter). It can really add a level of pizzazz to an already good system, so do check it out if you don’t want to spend thousands of dollars.