The two wires of the earphones are broken. Is there a positive and negative

chenbingjy

The two wires of the earphones are broken. Is there a positive and negative [Copy link]

 

First picture:

Both wires of the earphones are broken, and the search on the Internet said that there is no positive and negative. It also said that the paint should be removed.

There are two wires, one yellow and one green. Is the green one painted? How can I remove it? Thank you!

chunyang

It doesn't matter if it's positive or negative, but it's best to observe and judge the original connection method based on the broken wire debris. If the wire is enameled wire, you need to remove the paint, but enameled wire is rarely used for headphones. If it is, scrape it off with a knife and then solder it. Some enameled wires don't even need to be removed. They use temperature-sensitive paint, and the temperature of the soldering iron can automatically melt the paint layer. So, if you don't know how to judge, try to solder directly first, and then scrape it with a knife without eating tin. Remember to use rosin flux when soldering.

吾妻思萌

You can tell which part is which by looking at the fracture of the wreckage. Welding is a basic skill. I believe the original poster

dcexpert

Ordinary headphones are not divided

tagetage

Headphones are divided into positive and negative. If you look at pictures of headphone speakers, some will have positive and negative poles marked on them.

tagetage

Or color-coded.

chunyang

Don’t be dogmatic about the polarity of headphones!

If you are serious, the wiring of speakers and headphones does pay attention to polarity, which involves the phase of the sound, but this is only meaningful for multi-sound units. The original poster is only concerned with headphones, and they are regular single-coil headphones, so the polarity issue is meaningless here.

The reason why it is recommended to connect the wires according to the original line sequence is just to emphasize observation, and it does not involve the necessity of polarity. From the perspective of use, it doesn't matter if you connect them randomly, even if the phases of the two headphones are opposite, it will never affect the use.

tagetage

chunyang posted on 2023-2-8 20:30 Don't be dogmatic about the polarity of headphones! To be honest, the wiring of speakers and headphones does pay attention to polarity, which involves the phase of the sound, but this...

I don't agree with Chunyang on this point. The current in headphones is DC pulsation, not AC, so it has polarity. The easiest thing to observe is the subwoofer. Normally, the drum speaker moves outward. If you reverse the subwoofer speaker cable, the speaker moves inward, and the sound is completely different.

tagetage

chunyang posted on 2023-2-8 20:30 Don't be dogmatic about the polarity of headphones! To be honest, the wiring of speakers and headphones does pay attention to polarity, which involves the phase of the sound, but this...

Even if the phases of the two earphones are opposite, it will not affect the use at all - it will definitely affect, because the speaker has a structure. If the wiring is normal, you listen in front of the speaker, and if the wiring is reverse, you listen behind the speaker. In theory, the sound is the same, but in reality, it is affected by the structure of the speaker and the sound is completely different.

chunyang

tagetage posted on 2023-2-8 22:36 I don't agree with chunyang on this point. The headphone current is a DC pulsation, not an AC current, so it has polarity. The easiest thing to observe is the subwoofer, which is positive...

Look carefully - I said "Don't be dogmatic about the polarity of headphones"!

chunyang

tagetage posted on 2023-2-8 22:48 Even if the phases of the two headphones are opposite, it will never affect the use at all----it will definitely affect it, because the speaker has a structure, and if the wiring is normal, you are listening to the speaker...

Regarding speakers, there has never been a saying that "theoretically the sound is the same when listening from the front to the back". There is a paper cone in the front and a huge magnet and supporting structure in the back, so where does "theoretically" come from?

chenbingjy

chunyang posted on 2023-2-8 16:29 It doesn't matter whether it is positive or negative, but it is best to observe and judge the original connection method based on the broken wire debris. If the wire is enameled wire, it needs to be de-painted, but enameled wire is used for...

Thanks!

chenbingjy

tagetage posted on 2023-2-8 19:02 Or use color marking.

Thanks! Is the red color in the picture below the positive electrode?

wangerxian

It feels like there is a positive and negative, you can connect it directly, if there is no sound it may be reversed.

chenbingjy

tagetage posted on 2023-2-8 19:02 Or use color marking.

I don't have this headset in black or red.

tagetage

chenbingjy posted on 2023-2-9 09:11 Thank you! In the picture below, is the red one the positive pole?

The positive terminal is marked. It may be marked in various colors.

chunyang

While we are still talking about polarity, it seems necessary to talk about the polarity of speakers/headphones.

First of all, whether it is a speaker or a headphone, we do not consider the case of integrated active devices here. As for the speaker/headphone itself, its working condition is pure AC, not "pulsating DC". The concept of the post on the 8th floor is completely wrong, please note that it is completely wrong!

Some cheap digital headphone amplifiers, in order to save costs, do not use low-pass filters, but use the mechanical inertia of the headphone diaphragm to achieve low-pass equivalently. If the waveform loaded on the headphone is viewed with an oscilloscope against the ground, it is indeed a series of "DC pulses", but the circuits of these headphone amplifiers are all bridge outputs, and the headphones are not grounded, so there is no DC component. If the headphones are grounded, a DC blocking capacitor must be added. In other words, even with the cheapest digital headphone amplifier, the headphones still work under pure AC and there is no DC bias.

Important concept - all speaker and headphone cones/diaphragms must work in a state of equal forward and backward movement with the static position as the center, that is, when no power is applied. There is no unidirectional forward or backward movement. If the front and back displacements are different, the result is obvious distortion. The outward movement of the woofer cone mentioned on the 8th floor is actually a visual illusion and the different damping coefficients of the diaphragm system due to the limitations of certain speaker processes. The latter will not appear on the woofer of high-end speakers.

So why do speakers have polarity? The answer involves two aspects, the most important one is to unify the phase of the sound waves. The sound waves emitted by a multi-speaker system must be in phase, otherwise there will be superposition interference in space, and deliberately using this phenomenon is the so-called "active noise reduction". Another reason is to protect the structure of the speaker under special working conditions. Let's first talk about the definition of speaker polarity: if a DC current is applied to the speaker, if the paper cone moves outward, the voice coil lead end connected to the positive pole of the DC power supply is the positive pole. In the past, the most commonly used audio power amplifier was the OTL circuit, which is characterized by a DC-blocking coupling capacitor connected in series between the output end and the speaker, and its capacity is often large. During the power-on transient of the OTL circuit, the DC-blocking capacitor will be charged to 1/2Vcc. This process is the process of applying pure DC to the speaker, and the paper cone will move in one direction. This is the source of the power-on impact sound. Observing the structure of the speaker, we can see that the range of the cone movement is limited. Especially when moving inward, the voice coil support structure is likely to hit a hard structural part when the displacement is too large (the term is called "bottoming out"). Frequent collisions will cause the voice coil support structure to wear and then cause the speaker to be scrapped. Therefore, during the power-on transient state, the speaker cone must move outward. By the way, this transient process is also the fundamental reason why the observer has an illusion about the direction of movement of the speaker cone.

If there is no DC surge during power-on, can we ignore the polarity of the speaker? For a multi-speaker system, we can ignore it as long as the sound waves are in phase, and for a single-speaker system, we can ignore it completely. The mainstream of modern power amplifiers is the bridge-type Class D amplifier, which has no isolation capacitors.

Finally, let’s talk about headphones.

Without considering special multi-voice coil headphones, for conventional single-voice coil headphones, polarity does not matter, because headphones are different from speakers. In fact, headphones work in a single state, and there will be no mutual interference between the two headphones. That is why I said on the 7th floor that even if the phases of the two headphones are opposite, it will never affect the use. What if the headphones are driven by OTL circuits? It doesn't matter, because the voice coil of the headphones is very light, the diaphragm size is very small, and the movement displacement is also very small. Even if DC is applied to the power-on transient, it will not cause bottoming wear.

chunyang

Since the polarity of headphones is not important, why are there polarity markings inside the headphones? This is mainly due to the need for production process management, that is, strict consistency is very important to maintain product quality.

In addition, when designing the internal structure of some headphones, the negative pad is deliberately made larger, which was very common in the past OTL headphone amplifier era. OTL has grounding, and to avoid introducing interference, the headphone leads at that time often used shielded wires or quasi-shielded wires (not braided to save costs). In order to make the shielding layer easier to solder, the negative pad may naturally be designed to be larger, and some sophisticated headphones will ground the metal part of the headphones to enhance the shielding effect.

chunyang

Now let's talk about the subwoofer.

The characteristic of a woofer is that it has high power. Because the human ear is relatively insensitive to bass, but often prefers strong bass impact, the woofer is designed to have relatively high power. High power means a large displacement of the cone/diaphragm, which puts forward special requirements for the design of the woofer, that is, the design difficulty of the supporting structure increases. Is there a way to increase the sound power of the woofer without significantly increasing the cost? Indeed, there is, that is to increase the damping of the speaker cone moving inward to avoid hitting the bottom during high-power output. I have pressed the cones of some woofers and found that pressing inward is more difficult than pressing outward from the back, so I thought about why this happened, and the conclusion is to prevent hitting the bottom. Obviously, this will cause distortion. But it is not a big problem, because the human ear does not have a high resolution of the fidelity of bass.

As mentioned in the previous post, visual illusions and the different damping coefficients of the woofer's forward and backward motion can cause the observer to misjudge the direction of the cone's movement, but this should not be the case if the amplifier circuit is carefully analyzed.

chunyang

The above three posts should have explained the relevant issues clearly...