Integrated amplifiers buying guide
Lay the foundation for a great home stereo system
From smartphones to wireless powered speakers to surround sound home theaters, there's certainly no shortage of ways to enjoy your tunes these days. But if you're a serious music lover ready to enjoy your music through a great pair of speakers, then a sound system based around an integrated amplifier might be just the ticket.
So just what is an integrated amplifier?
An integrated amplifier is actually two components in one — a power amplifier, which generates the wattage needed to drive your loudspeakers, and a preamplifier that accepts the inputs from all of your music sources, such as your CD player, turntable, AM/FM tuner, or network music player. The preamp also lets you switch among your sources and control the volume of your music. The preamp may also include balance and tone controls.
Stereo receivers are basically integrated amps with a built-in radio tuner. If you don't plan on listening to the radio, an integrated amp might make a better choice.
While amplifiers and preamplifiers are found within every music playback system, combining a preamp and power amp into a single shared chassis saves space and cost (compared to separate stereo amps and preamps).
What to look for
One of the most important things to consider when choosing an integrated amp is the number and types of connections it provides. You'll want to be certain that it can accommodate the components you currently have, as well as ones you may possibly want to add in the future.
The Cambridge Audio Azur 851A integrated amplifier includes plenty of analog RCA audio inputs, including two pair of balanced XLR jacks for connecting high-end gear.
Analog audio inputs
- RCA audio inputs are the standard for connecting audio components. Almost every source component has RCA outputs.
- An RCA phono input is for direct connection of a turntable without a phono preamp. Some can even accommodate moving coil cartridges, as well as more common moving magnet ones.
- Balanced XLR audio inputs are heavy-duty, locking three-pin connectors designed to connect high-end audio components.
Integrated amps like this Yamaha A-S801 provide analog as well as optical and coaxial digital audio inputs, plus a USB connection for streaming music from your computer.
Digital audio inputs
Some Integrated amplifiers include a built-in digital-to-analog converter (DAC) that can accept digital audio signals from compatible components — including many HDTVs, CD/DVD/Blu-ray players, network music players, and computers — and convert those signals to sound. The main types of digital audio inputs to look for are listed below.
- Optical (Toslink) and Coaxial (RCA) digital audio inputs provide a connection for many digital music sources, as well as sound for video sources.
- A USB (Type B) connection lets you plug in a computer to listen to streaming or stored music files. The DACs in some integrated amplifiers can even decode high-resolution music files. A few also include a front-panel USB port (Type A) for playing and charging an iPod or iPhone, or plugging in a USB thumb drive.
- An Ethernet port makes it possible to connect your integrated amp to a computer network, and access music from network storage devices, the Internet, and compatible network-connected computers.
It's hard to beat the convenience of wireless streaming when it comes to music listening. A number of integrated amplifiers now offer that capability in several different ways.
- Built-in W-Fi® allows you to connect your amp to your home's wireless network to stream music from network-connected computers and music servers.
- Bluetooth® connectivity lets you enjoy instant wireless music streaming from any compatible smartphone, tablet, or computer. Some integrated amplifiers have this feature built in, while others may offer it as an add-on option.
- Integrated amps with Apple AirPlay® can stream music from your iPhone® or iPad®, including from apps like Spotify® and YouTube™. If you have a networked computer running iTunes®, you can also use AirPlay to send music from your music library to your integrated amp. If your iPhone or iPad is connected to the same network as your computer, you can even use the Apple Remote app to control iTunes playback.
- A headphone jack provides a great way to enjoy your music without disturbing others.
- A Subwoofer output lets you connect an optional powered sub to supplement your system's bass output. This can be especially convenient if you're planning to use your system for movies and TV or with bookshelf speakers.
- Some integrated amplifiers provide Preamp out/Main in connections that allow you physically disconnect the amplifier and preamplifier from each other in order to use them independently. These connections can also provide a way to insert an equalizer or signal processor into your system. Other integrated amps may offer a basic preamp output for an easy way to add a new power amp to your system — handy if you move your system to a larger room, or happen to upgrade your speakers to ones that need more power.
- Some integrated amps have only one pair of speaker connectors — perfectly fine if that's all you plan on using. The dual A + B speaker connectors on other amps offer an easy way to connect two pairs of speakers, handy if you want to power a second pair in another room, or even outdoors. These dual outputs can also provide a convenient way to bi-wire a compatible pair of loudspeakers.
Integrated amps come in all shapes and sizes, and it's likely that physical dimensions will play an important role when choosing. If you have plenty of open space or a large equipment rack at your disposal, then a classic, full-size amp might be the way to go. These traditional components usually offer the greatest number of connections and flexibility for larger systems with numerous components.
On the other hand, if space is tight, a compact desk-top style amp could fit the bill nicely. Although these mighty mites may provide fewer connections overall, they can usually accommodate most systems while fitting comfortably into smaller spaces.
Power: How much and what kind?
Although it seems as though power output would be the first thing to look at when choosing an integrated amp, it makes less difference than you might expect. Why? Because wattage ratings and maximum volume, which are often thought of as going directly hand-in-hand, are actually only loosely connected to each other. For example, a 200 watt amplifier will only play a mere 3 dB louder than a 100 watt amplifier — a barely noticeable difference. To play twice as loud as that 100 watt amp, you would need one with 1,000 watts, a ten-fold increase in power!
So what determines how much amplifier power to get? Basically it comes down to your speakers' sensitivity (or ability to convert power into sound), the size of your listening room, and the volume levels you're likely to want. While there's no single or simple answer, the general rule of thumb is: the larger your room, the less sensitive your speakers, and the louder you like it, the more power you'll need.
For example, a desktop system that only needs to play at moderate volume levels with speakers placed very close to you can easily work with 15 to 20 watts per channel. Conversely, a system in a large listening room with lots of sound-absorbing surfaces such as heavily padded furniture, drapes, and rugs, driving low-sensitivity speakers to high volume levels may need 200 watts or more. Our experience shows that most speakers perform their best when being powered by an amplifier that's as close to their maximum power rating as possible, but you don't absolutely need that much to enjoy good sound.
One last thing to keep in mind when it comes to matching integrated amps with speakers, and that's impedance. Almost all amp manufacturers list a minimum recommended speaker impedance, such as 8 ohms or 4 ohms, to use with their designs. To be on the safe side, it's best to always follow those recommendations. Keep in mind that using 2 pairs of speakers simultaneously with an amplifier that has A and B speaker outputs changes the impedance numbers. Always double check the owner's manual to make sure you are operating within the safe limits of the amp.
The Yamaha AS3000's large toroidal transformer delivers plenty of clean, low-noise current. The amp's internal left- and right-channel circuitry has been deliberately placed as far apart as possible to reduce cross-channel interference, preserving the integrity of each channel's output to your speakers.
Amplifier class and construction
When shopping for an integrated amp you're likely to come across terms relating to amplifier "class," such as Class D, Class A, and Class A/B. Much has been made of these class designations, and how they relate to sound quality. The distinctions are very technical, but our experience has shown that there are great-sounding amplifiers within all of these classes. Bottom line: try not to get too hung up on these designations.
Amplifier classes aside, there are some tangible features to look for that affect an integrated amplifiers performance. One of more important among them is an amp's power supply, or the internal circuitry that converts AC power from the wall into DC power used by the amp. As a general rule, better power supplies frequently include ring-shaped toroidal transformers that efficiently deliver large amounts of current with a minimum of physical vibration or radiated electronic "noise" that can adversely affect sound quality.
Another feature to consider is dual-mono construction, which attempts to separate the right and left channels from each other — both physically and electronically — in order to maintain maximum stereo separation for a wide, deep musical soundstage, and to minimize the two channels from interfering with each other.
Why choose an integrated amp over a receiver?
A home theater receiver and a room full of surround sound speakers is dynamite for movies. But if you're building a system primarily for music listening, an integrated amp is a better choice. Since integrated amps focus only on the components that count most for getting top-notch sound, you're not investing in additional circuitry and processing unneeded for two-channel audio.
Even without surround sound, though, an integrated amp and stereo speakers can greatly improve TV sound. Many models feature digital audio inputs to connect a TV or Blu-ray player. It's a cost-effective, space-saving way to build an excellent two-channel system for music, movies, and TV. Many integrated amps also offer an output for a powered subwoofer — perfect for augmenting bookshelf speakers with more bass or for explosive sound effects with movies.