How To: Pair Your Headphones With A Headphone AmplifierCategories: Headphones

As with anything and everything in the vast and sprawling hi-fi Kingdom, there comes a time when one will ask… which headphone amplifier should I pair my headphones with? It’s a very good question and, as with everything else hi-fi, to a certain extent it does boil down to personal choice. But there are a few key things that should help you along the road to head-fi heaven.

But firstly…

Why Do I Need One?

Need is a strong word – the vast majority of headphones will work with any headphone socket on any old integrated amplifier (and plugged straight into the source in the case of portable headphone players – although you may need a 3.5mm AUX adapter with any high-end headphone). But if you’re serious about your sound (and lets face it – you probably are!) the thought of plugging a decent pair of headphones either straight into the source or into a sub-standard amplifier probably makes your toes curl. And it should!

Headphone sockets on most integrated amplifiers and source components are generally last minute additions which are not designed to get the most from the delicate and complex workings of your headphones. Headphones are – essentially – a pair of speakers strapped (comfortably) to your head. That is all that they are. And much like speakers, they need the correct amplification in order to fully realise their potential. A lack of amplification means there’s a very good chance your headphones will sound quiet, tinny and generally disappointing. And if you are looking at spending anything over a few hundred on yours, you will notice a difference once an amplifier is paired.

The Science

We asked our resident techie Richard on the science behind finding a fitting match in a headphone amp, and he had this to say:

“It all boils down to the power output ratio vs the impendence of the headphones. The higher the impedence of the headphones the greater power the headphone amplifier needs to be.” 

Got that? Good.

In order to fully understand what that means, we have to talk about ohms and impedance. Are you ready?

In short, an ohm is the unit in which impedance is measured, and the property of a pair of headphone that restricts the flow of electrical current. The impedance of a unit is fixed, which means it is a reliable unit of measurement for headphones (and what kind of power they will need). It is pretty imperative to understand the output of ohms from the amplifier and the impedance of the speaker, as not doing so can result in a blown driver. Or worse: poor sound quality !

Ohm’s Law states that in an electrical circuit, current flow is directly proportional to voltage and inversely proportional to impedance.  Mathematically, this becomes: Current (in amperes or I) equals voltage (in volts) divided by impedance (in ohms).

By knowing the voltage and the total current, it is possible calculate the total impedance of the headphones by dividing the voltage by the total current. To quote from the above linked article:

‘As an example, if a (solid state) amplifier is producing 10 volts AC to an 8 ohm speaker, the current in the speaker will be 10 volts / 8 ohms or 1.25 amperes. If the amplifier output is increased to 20 volts to that 8 ohm [headphone], the current becomes 20 Volts / 8 ohms or 2.5 amperes. So increasing the voltage increased the current. If the voltage decreases back to 10 volts, the current will decrease back to 1.25 amperes. Now, if our amplifier with 10 volts output is connected to a 4 ohm [headphone], the lower impedance will allow more current to flow. The amount will be found by 10 volts / 4 ohms = 2.5 amperes.  If we use a 2 ohm speaker, even more current flows: 10V/2 ohms = 5 amperes.’

Luckily, the impencance of the headphones and power of the amplifier is usually clearly stated on the units, if not on their packaging. So it’s pretty straight forward, as long as you have those two bits of info – working out the correct amp/headphone match (in terms of impedance/power isn’t difficult. The rest, I’m afraid, is down to your own personal preference.

The Perfect Pairing?

Ensuring compatibility between your headphones and headphone amp is the key to getting the absolute most out of your headphones drivers. Plug a pair of HD800s directly into a iPhone and you will be using the cans at a fraction of their capacity. But pair them up with a decent headphone amp at a similar price point (it is a recommended that you spend at least 50% of what you have spent on your headphones on a corresponding amplifier) and you will there will be a marked improvement in the sound quality.

You don’t have to stay at home to enjoy the sonic-superiority of properly amplified headphones either – there are a oodles of portable headphone amplifiers (from budget to high end) that will really get the most out of your portable player. And don’t worry, there are hi-fi versions of those as well. So if you think about it, there’s no excuse for poor sound quality, in any format. You can literally enjoy hi-fi quality wherever you go.

As for the perfect pairing… well. There are a few obvious choices. The Oppo HA-1 with the Oppo PM-1s (pictured above) are an obvious choice, and we actually offer package deals on the Sennheiser HD800s with the Sugden HA-1 and the completely bonkers Ergo AMT Headphones with the AMP 2 (you have to hear that pairing to believe it. Headphone mono-blocks!) but on the whole, it isn’t an exact science. We have talked about high-end pairings before, but those choices are a little more obvious than anything slightly lower down the line.

Our advice? Chop and change and see what you fancy. Or even ask our advice! If you have a piece of the puzzle in mind, we can likely recommend the corresponding piece. After all, it’s what we do.