If you are a fan of high-quality headphones, you must already know the amp very well and already have a few. But for most headset users, the headphone amp is still a relatively unfamiliar concept. The headphone amplifiers on the market today cover all price areas from cheap to very expensive, so it is important to understand their purpose and when they are needed.
What is a Headphone Amp
Headphones are a pair of miniature speakers. All speakers need an amplifier (AMP), and each headset cannot work without an amplifier. But the existing devices that can play music have an AMP, whether it is a smartphone, a CD player, and every computer and laptop. So why do we still need an external, independent headphone amplifier?
These built-in headphone amplifiers(laptop, phone,etc.) have made a significant compromise, making it work only in a limited space and power. An independent amp will have more space for an excellent circuit and a more powerful power supply, which will allow the device to control the sound better. For some headphones, power is significant.
The amplifier needs to have enough power to control the music well. Not to say that you need to blow your ears, but to control the music to reach the peak without distortion. That will make you feel that under a high-power amplifier, the sound will become cleaner and better managed. But you must learn to use them safely and keep the volume consciously within a comfortable range.
So, how to judge whether your earphone needs an amplifier? We are going to look at some performance of the headset, but the most important thing is to observe the sensitivity and impedance of the headphone.
The sensitivity of the headset indicates how much volume the headset will emit at a specific amplifier power. Specifically, how many decibel levels the headset will reach at 1mW of power. A very sensitive headset can achieve 100dB (or more) sensitivity at 1mW. In-ear headphones are in this range, and these high-sensitive headphones do not require a dedicated headphone amplifier to drive them.
The sensitivity of many non-portable high-quality headphones is generally not very high. It is necessary to have an external amp when the headphones’ sensitivity is 95dB or less.
Another point is the relationship between the impedance of the headphones and the output impedance of the headphone amplifier. In general, the impedance of the headphones should be eight to ten times the amplifier’s output impedance. When the output impedance of the amplifier is much smaller than the impedance of the headphones, your sound will be more compact and neat.
Advantages of High Impedance Headphones
The design of high impedance/low sensitivity is, first of all, because those high-end headphones are designed with large-size moving coil units. Low sensitivity is essential for the control of the overall sound, and it can also obtain a better low-frequency response. And for large sizes, For the moving coil unit, the diaphragm in the unit has a specific thickness, and only enough current can pass to drive the diaphragm better. Besides, the high-impedance design can also better filter out the noise in the signal, and if the driving voltage is sufficient, the high-impedance will bring a higher conversion ratio.
Good sound needs to be pushed out. Since the impedance is small and it is easier to make a good sound, why are there so many headphones with hundreds of ohms? What needs to be emphasized here is that although there is no absolute relationship between impedance and sound, there will still be Some influence. The sound of high-impedance headphones is more relaxed and natural, and the sense of hierarchy in low, medium and high frequencies are better. That can be found by comparing the headphones of different impedances of the same model. But for different types of headphones, there is no comparison. Because even low-cost high-impedance headphones, the sound can not reach the level of low-impedance high-end headphones. But headphones with high impedance require the player to have a higher power output. It is difficult for ordinary CD players and players to drive headphones with an impedance of hundreds of ohms, so audiophiles will choose external amps to drive.
Types of Amps
The types of amps currently on the market include desktop amps suitable for home use, portable amps that can be carried around, and decoding amp all-in-one machines (also divided into desktop and portable).
Any amplifier with high-quality components and power supplies will provide better sound quality for headphones, regardless of volume level. Remember, we consider amplifiers because we need the output to be cleaner and tidy and free of distortion when our sound reaches its peak. A high-quality headset can show excellent sound in any scene. But without a good amp, even high-quality headphones can’t achieve its peak performance.
All in all, finally summarize two points; in the three cases of the audio source, headphone, and amp, the audio source is the most important, followed by the headphone, and finally, the amp. If you are using low-impedance, high-sensitivity headphones, a mid-to-high-end player is enough. No amp is required. But if you are using high-impedance, low-sensitivity headphones, you need to use it with an amp.