How to set up an AV amp
FROM PAIRING AND PLACEMENT TO UPGRADES, ALL YOU NEED TO KNOW.
WHETHER YOU’VE ALREADY chosen amplification for your system or are yet to exercise your purchasing power, this guide will ultimately help you unlock a stereo amplifier’s full potential.
While we like the idea of plug ‘n’ play set-ups as much as anyone, there’s more to getting the best out of stereo amps than simply powering them up on a hi-fi rack, plugging in speakers and going wild with the volume dial.
From pairing and placement to connections and upgrades, there is plenty more to consider…
INTEGRATED VS PRE/POWER
If you’ve already purchased an amplifier and are now eyeing up your latest purchase with a view to getting started, you may wish to skip straight to the ‘system matching’ section.
But if you’re reading this before you’ve chosen the amplification to drive your system, you have an important decision to make. Do you go for an integrated amplifier or separate pre/power boxes?
The former tends to be the cheapest, most convenient option – it packs both pre- and power amplification into one chassis. This means everything has been tuned together, saving you the work that goes into matching separate amps.
Two-box amplifiers involve splitting pre-amplification (input selection and volume control) from power amplification. The idea is to keep the sensitive preamp circuitry (and the audio signals flowing through it) away from the electrically noisy high-current power amplifier section. Having separate power supply sections helps improve sound. So you double your component count and increase the cost but, as long as your pre- and power-amps function together, you should enjoy better performance.
The most obvious way of selecting pre- and power amplification that works together well is by sticking within one brand’s range. Invariably they will have been tuned to work well together. If you plan to mix and match, be aware some pairings will work better than others – the best way to find out is trial and error.
And that’s true when it comes to matching source components to your amplification. Sonic affinity can be determined by common sense to some extent. If your source – a CD player, for example – sits on the bright side of neutral, it shouldn’t be partnered with a stereo amplifier with a similar character.
SYSTEM MATCHING
An amplifier’s partnership with stereo speakers is extremely important, and there are a few things worth considering. Ever scratched your head when faced with specs such as ‘75W into 8 ohms’? Allow us to explain.
The speaker/amp partnership not only comes down to an amp’s power output (how many watts it can deliver to each channel of a music signal) but also impedance
IF YOU’RE READING THIS BEFORE YOU’VE CHOSEN THE AMPLIFICATION TO DRIVE YOUR SYSTEM, YOU HAVE AN IMPORTANT DECISION TO MAKE. DO YOU GO FOR AN INTEGRATED AMPLIFIER OR SEPARATE PRE/POWER BOXES?
characteristics (in ohms) and sensitivity (dB) of the speaker.
Impedance is a measure of how difficult the speaker is for the amplifier to drive. The sensitivity of a speaker, meanwhile, is a measure of how loud a speaker will go for a given input.
The standard way to measure an amplifier’s output is by connecting it to an 8ohm resistor and measuring the power before distortion becomes too high. However, the electronic load of a speaker is far more varied than a simple resistor, so be careful about judging an amp simply by its 8ohm power figure.
A better insight into an amp’s muscle is to compare its power output into 8ohms with that into 4ohms – an ideal amp doubles output as impedance halves. Though you may be tempted to go for the most powerful amp, if you listen at high volume, you’re better off with a sensitive speaker. That’s because an amp’s output has to double to match a 3dB increase in speaker sensitivity.
But numbers tell you only so much, and the best test to gauge if components work well together is to have a listen.
PLACEMENT
So you’ve found a match. The next question is where to put it? The surface your stereo amp sits on can make the world of difference to its performance. Furniture might not be at the bottom of our list (that’s the floor), but we’d suggest placing it on a dedicated hi-fi rack.
Your choice of rack shouldn’t be based on looks alone. Different materials have different acoustic properties, so take that into consideration too. Generally speaking, glass shelves encourage kit to sound forward, while wooden supports result in a more rounded balance.
All that power under its hood can build up a temperature, so it’s important to give an amp some breathing space to stop it running too hot.
CONNECTIONS
Before you place its back to the wall, it’s worth looking at your stereo amp’s rear panel to see what options are available regarding connecting sources, extra speakers and future upgrades.
All stereo amps have line-level RCA inputs, which can be used for all the usual sources – streamers, CD players etc. One of those connections is sometimes a phono input, designed specifically to be connected to a turntable and handle the low signal levels and extra equalisation required for such a source.
Three-pin XLR connections carry balanced audio signals. These are usually found in higher-end and recording-studio products. Its main advantage is that it rejects high levels of electrical noise, making the most sense when used in electrically noisy environments or over long cable runs, say 10m or more. Balanced operation doesn’t always sound better, though, and much depends on the components used.
Rega is among the brands to have stuck to analogue-only amp, with its Award-winning Brio, Elex-R and Elicit-R models. But, even in the budget market, many stereo amps now have a digital-to-analogue converter (DAC) – and digital inputs – to increase their versatility.
If that sounds like yours, you might be faced with several types of digital inputs. Optical connections transmit a digital signal from one device to another via fibre optic cables and laser light, while the equally common coaxial carries signals electrically. USB inputs, which come in various forms, are often present for the playback of USB sticks, laptops or hard drives, too.
The Marantz PM6006, Moon 240i and Cambridge CXA60 are all well-connected stereo amps. You can plug your CD player, streamer or laptop into the amps via their multiple digital inputs. Usually the performance of an integrated DAC doesn’t match that of an outboard DAC.
Bluetooth is increasingly on the features list. The Audiolab M-ONE and Cyrus One have built-in Bluetooth, while the Cambridge CXA60 has it through a dongle add-on. The NAD C 368 even has wi-fi onboard for network streaming, although that’s unusual for a stereo amp.
Regarding outputs, there’s often one for adding an external subwoofer to give extra sonic heft. Tape outputs are fixed line-level outputs (ie, not affected by the amplifier’s volume control) that send a full level signal to the connected kit – normally a recorder. But one of the most common inclusions is a 3.5mm or 6.3mm headphone output, which often features on a stereo amp’s front panel.
Some stereo amps also have two sets of speaker terminals – usually labelled ‘A’ and ‘B’ or ‘1’ and ‘2’ – which allow you to run two pairs of speakers at the same time (in different rooms, for example), although this can have a detrimental effect on performance as the amp’s power is shared multiple ways.
BI-AMPING
There’s also the option of bi-amping, which requires at least two stereo power amps (unless you have a multi-channel receiver with spare channels) and some more cables. Each amp handles certain frequencies or channels, instead of one handling all. By reducing the number of drive units an amp needs to power, you make its job easier and it sounds better.
UPGRADES
Upgrading doesn’t necessarily mean out with the old. Your amp may already have an upgrade path. Some manufacturers, such as Naim and Cyrus, have dedicated connections for external power supplies.
If an integrated amplifier has pre-amp outputs, then using it solely as a pre-amp and passing amplification duties onto another amp, is another way to upgrade.
There’s also the option to upgrade your amplifier’s mains cable, so we’d take advantage of the fact most dealers will let you try before you buy.
Whatever the rest of your hi-fi system and your future plans for it, introducing a new stereo amplifier requires some thought and a bit of advanced planning. If you bear in mind everything from the type of equipment your amp is going to be paired with, to the type of rack you will put it on, and consider your options for future upgrades, then you’re destined to make the most of your amplifier.