Headphone amplifier – amplified into the ear

Headphones are trending. And the better the speakers sit directly on the ear, the more they need proper care. This is where headphone amplifiers can make a big difference. For stronger sound that is good for the ears in many respects.

As a mobile companion on your smartphone, a sound supplier on your computer, or as a music pamperer on your home hi-fi system – headphones are now simply part of the basic electrotechnical equipment. But they simply can't be good enough, as any ear specialist will confirm that bad “earphones”, as we now also call them, are a danger right here, on the ears. And what’s broken on or in the ear can never be repaired again.

Despite what may be well-intentioned instructions, it is not even the objective volume that primarily kills the sensitive cells in the inner ear. Of course, continuous pounding at hammer drill level will destroy quickly and without fail. But naturally with reasonably “civilian” conditions – volume is not the same as loudness. Distortions in particular can increase the subjectively experienced volume until it becomes unbearable, while undistorted, clear sounds can be heard enjoyably, even at very high levels. Painful levels, let’s say as a rule of thumb, are more dangerous than pleasant ones. .

So why use headphone amplifiers at all?

This is where they come into play – the headphone amplifiers. Whether visible or not, they are in every device that has a headphone connection, usually a 3.5 mm diameter jack plug. Sockets for 6.3 mm diameter connectors are also used in the home sector. There are other types, but we’ll get to that later. And unfortunately, behind these sockets, most smartphones, tablets and computers have the cheapest junk as an amplifier. A thrifty op-amp for under 30 cents – that's it. Why? Manufacturers want to cut costs, and mobile devices at least should use as little power as possible.

Let’s leave headphones aside for the moment, because they deserve their own blog part. Ideally you’ll already have gotten rid of the cheap accessory jokes that came with your mobile device, or you’ll want to replace them. And you or your kids won’t let the cheapest low-quality model bash your eardrums when gaming or listening to music on your computer. Always remember – your ears deserve quality, whether you listen with an in-ear (plug in the ear), on-ear (sitting on the ears) or over-ear (enclosing the ear).

If you can’t listen loudly, can’t listen loudly with good quality, or can’t listen loudly for long because of swollen, imprecise bass, unclear vocals, or harsh or muffled highs, it’s time to invest in good headphones. And then immediately consider buying a headphone amplifier that is suitable for the listener’s intended purpose. .

Mobile Entertaining

As we know only too well, when doing sports every other part that dangles around beside the smartphone is simply a nuisance. Low-impedance receivers are a prerequisite for outdoor listening. With values between 10 and 50 ohms (on the packaging or in the description), they don’t consume as much of the power from the supplier’s batteries. If you really want to enjoy your mobile music when running in particular, you should get yourself some light, battery-powered headphone amplifiers, which you can simply fix to your belt or jersey. Suitable models start at around EUR 40.

The additional “load” and the fact that an additional battery should always be charged as much as possible, however, are always a disadvantage. Just please don't expect any earth-shattering advances in sound quality. To be honest though: If you are out and about you might not need an absolute high-end playback as the background music to your puff and panting.

In the gym, where you do more lifting, stepping or sitting than running around, you can definitely use a more powerful battery-operated headphone amplifier, always small enough of course, to easily fit into your sports bag or under the towel you take with you from machine to machine. Here too music is only the secondary motivation for muscle building, but as with the jogging listener, above all it’s about being more gentle on the ear drum.

If you make longer trips on buses or trains, you might be able to hide somewhat bulkier headphone amplifier models in your briefcase or school bag. Powerful amps are always worth the effort here anyway. Ambient noises should be drowned out distortion-free. And some of you may already have headphones with noise canceling. This suppression of surrounding sounds is a practical affair. In any event you can always turn up the headphone amplifier quality here.

On the system

If you still enjoy old-fashioned CDs or LPs or also pop high res files into a top quality hi-fi system, you might not also be able to turn up your amplifier just as you want at any time of the day or night. The CD player might even have a headphone output, or perhaps it is on the central amplifier instead. In the affordable range in particular, however, even with good amplifiers (integrated) the headphone outputs tend to be somewhat of a developer afterthought, with their cost-conscious controllers also eagerly targeting them with budget cuts. So a 08/15 op-amp must often also do its alibi work behind the jack socket here. Anyone who has really good headphones will of course want the best possible care for them. Let’s leave out the special case of electrostatic headphones that high-end users love here, as they have their own power supplies because of how they work. But the hi-fi market also offers solutions here for electrodynamic ear speakers (these being the vast majority), ranging from about EUR 150 up to some EUR 10,000. What they all have in common, however, is the fact that they can also easily supply high-impedance headphones (from 200 to 600 ohms and more) with sufficient power, and many models even come with two connections. There are even headphone amplifiers with separate volume control for a second listener. While we’re on connections: To be able to loop a separate headphone amplifier into the hi-fi system you need a fixed output on the (pre-)amplifier. This is usually the “tape out”, where there is a fixed level independent of the amplifier’s volume control, which in turn supplies the headphone amplifier’s inputs. Incidentally this is normally possible without any problems up to cable lengths of three meters, so if the cable is okay for you, you can place the headphone amplifier right beside your listening spot. There are of course wireless solutions, but I have yet to hear a satisfying high-end option. You then adjust the listening volume on the headphone amplifier. Some models also offer special goodies such as tone control, which can be great, depending on your musical taste and sound preferences. A lot of the top quality headphones today are pretty “mild” and are tuned with a pretty strong bass. If it’s more treble and slimmer bass you’re after, you can adjust here accordingly.

On your computer

If you enjoy your music, at home as well, via your tablet, laptop or for the most part on your computer with headphones (whether from a hard disk or streamed), it’s relatively easy to upgrade on two harmonious sound fronts, because the sound is of course digitally stored and processed in digital devices, but we humans continue to listen in analog – so we need a digital-analog converter, or DAC for short. In computers these are implemented on the sound cards, and for the most part are not really all that high-end.

In practical terms, of course, there are quite a lot of headphone amplifiers combined with a DAC. You can always get better quality converters than you would normally find in computers, starting at about EUR 200. This begins with an own power supply for the electronics – in the computer the poor chip has to share the power with dozens of other elements. So if you want better sound on your computer, you should have a look at the various DAC/headphone amplifier combinations, and there are plenty to choose from. If you do though, you should first ensure the right interfaces are provided on both sides. And if you stream in high quality (high resolution), you must of course also check that the DAC can process high data rates accordingly. But thanks to long since correspondingly equipped standard ICs, most external converters can even manage rates with 24-bit word width and 192 kilohertz sampling frequency. For the non-technical: That's about 1,000 times as much data per second as you get with a CD.

At the top

And then there are also special switching tricks, such as “Crossfeed” for example. The problem with headphones, generally speaking, is the fact that the separation to the left and right is extremely high. But via speakers, and of course in real life, we can also hear sound from the left ear in the right ear with a minimum time delay, and vice versa. Many consumers are frustrated by the lack of a “stage” in front of them when listening with headphones, as signals mixed in the center – like the vocals in most pop songs – seem to play directly in the middle of their head. Crossfeed, for instance, transmits signals from the left channel to the right and the other way round with minimum delay and the right dampening. Depending on how well the circuitry is configured, the sound can be astonishingly good and wonderfully spatial.

As a manufacturer, McIntosh, for example, has also installed the effect in its latest generation of integrated amplifiers – needless to say the high-end amps from the USA aren’t cheap.

But even “pure” headphone amplifiers can be really expensive. Whether a headphone amplifier works with transistors or with tubes, is not a quality issue. With their “good-natured” distortion behavior, tubes, however, can produce an entirely more enjoyable headphone sound in the higher-level price segment. As for sheer power output, tubes are usually inferior to semiconductors. But headphones need much lower voltages and currents than speakers. And above all the circuitry should sufficiently control the noise (especially annoying with headphones) of the glass bulbs.

It works, but it will cost you. A cheap Chinese tube is certainly no guarantee of a nice harmonious sound. So be careful with allegedly cost-effective pseudo high-end offers. At the other end of the scale: With the V 16, for example, Octave, the high-end German manufacturer, produces one of the world’s best headphone amplifiers. It’s so good that while being developed it became a routinely integrated amplifier, despite its low output. This excellent product, however, costs about EUR 10,000, and it’s not even up there with the absolute world leaders,

where other connector options are now also possible. At the outset, we defined the 3.5 mm and 6.3 mm connectors and sockets as standard. With the connectors we see a three-way shaft split. One segment carries the signal marked with “+” for the left, the second for the right, the third the shared earth marked with “-”, which also provides the shielding. To minimize the disadvantages there are now also alternatives for high-end listeners, with, for example, two separate cables with jack plugs, with two XLR connectors or with a cable with a four-pin XLR connector. The balanced connection carries the normal “+” signal on one line and the inverted “-” signal with phase rotated by 180 degrees on the other. Disturbances cancel each other out where the two meet again, at the headphone diaphragm. Technical jargon? Yep! In ordinary English: The signal is flawless from beginning to end.

My conclusion

More important and far cheaper, of course, is the news that you can do your ears a lot of good for relatively little money. Firstly with good headphones and secondly with the right headphone amplifier. They literally benefit the ears right there on the ears. And every cent you invest in your most sensitive sensory organs, is worth it for life.

in-akustik Headphone Amps