What's the point of balanced cable if the connectors are 3.5 mm (aka not balanced)?

I am not the most educated person about cables - especially in weird setups like the following. If a headphone has 3.5 mm connectors, what exactly is the purpose of using a balanced cable that has a balanced end (2.5 mm, 4.4 mm, XLR)?

Now, I am aware that there are some headphone that have balanced connectors (usually 2.5 mm) and do not have a balanced end (3.5 mm or 6.3 mm), but you can always buy a cable that is fully balanced (both the connectors and the end are balanced), so it leaves me to wonder what is the purpose of using a balanced end if the connectors aren’t balanced.

One example of the first case would be the Meze 99 Classic - Meze sells a balanced cable for that headphone, but the 99 Classic uses 3.5 mm connectors.
I own the iBasso SR2, and it also uses 3.5 mm connectors - which leaves me to believe that there is no way it can be balanced - yes you can use a cable that has a balanced end, but would this do anything besides allow you to plug it in devices that have balanced outputs?

Edit: Just for reference. iBasso SR2 uses TRS 3.5 mm connectors, while Meze 99 Classic uses TS 3.5 mm connectors

I am quite curious about this, and would definitely like to better understand it. This being said, I would appreciate anybody’s contribution!

As long as the cable has 4 contacts at the amp end and 2 contacts at each ear on the headphone, it is balanced (unless it was wired otherwise internally but I don’t see why that would be done as it would be idiotic).

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Hm. This leaves me to further wonder - does this mean that almost any headphone can be balanced out?

Both iBasso SR2 and Meze 99 Classic use separate connectors (one on either side), while some other headphones only use a single one (e.g. Sennheiser HD598). Does this also matter? And is there any difference if the 3.5 mm is TRS (iBasso SR2) or TS (Meze 99)?

But also leaves me questioning why some manufacturers would use 2.5mm termination for the connectors? Is there any change or benefit by using 2.5mm at the connectors?

How exactly can I check/know this?

Sorry for the many questions, let’s just say I am a little bit curious about cables atm

Most headphones with connections on each ear can be balanced, some with one connection cannot without modification, see the threads here with making various Beyers balanced.
I believe you can get a balanced cable for a 598, it has a modified 3.5mm (I think) TRRS connector at the headphone (i.e. it has 4 connections).

The important part is you can’t connect a single ended headphone to a 4 pin XLR on an amp without risking damage to the amp. In doing so you short two signal lines from the amp together.

Balanced has been discussed ad infinitum here.

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First of all thank you for the straight forward answer.

So this means that this is the downside of using 3.5 mm connectors? If a headphone has 2.5 mm connectors (one on either side), this allows the use of 4 pin XLR on the amp end?

Sorry if the same questions keep rotating… Did some quick Google searches and couldn’t find the answer - so thought I’d ask here

The connector doesn’t matter, except in so far as SE vs balanced, you can listen to SE out on an amp with a balanced adapter, but NOT the other way round.
The reason you want balanced in a headphone or IEM is if you have an amp with a balanced topology it will likely be at least one of either louder or better.
The amp designed of a balanced amp has to convert that to SE so you can use a single ended connection, there are various tradeoff’s in doing that discussed elsewhere.

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I’m not fully clear on this question…so I’ll answer what I think you’re asking. All headphone/speaker drivers have 2 electrical contacts on them that are often labeled as in/+ or out/-. The labeling is just to make sure the end user can wire everything in phase. Truth is, both contacts serve as in and out because an audio signal is an alternating current signal. For a stereo headphone, this means you need 2 wires per side. To power a headphone balanced, you need 4 connections to the amplifier. A “single-ended” headphone has taken one contact from each driver (usually the “-”) and wired them together at the amp end. This means that the “+” contact on each driver gets its own direct connection to the amplifier and the “-” sides share a connection to the amp. That is why a single-ended connection only has 3 contacts. Headphones like the Beyer DT series are "single-ended’ because they have wired those two “-” sides together inside the cup and the headphone cable the goes to the amp is basically just an extension cord. To “balance” them you have to open them up and rewire those “-” sides so they can be directly contacted to the amp inidivdually.

Headphone drivers DO NOT CARE whether they are connected via a balanced cable or a single ended cable. All the electrical signals look the same to them either way. Where balanced matters - IF it matters for your situation - is in the amp and dac. Now, as @Polygonhell points out, if you try to plug a SE connector into a balanced jack, you will short out the amp - meaning you will connect things that aren’t supposed to be connected - and that can cause problems. The type of balanced connector doesn’t matter either as long as there are at minimum 4 unique electrical contacts.

I hope that all made sense.

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Aha, makes more sense now. Thanks!

Now, the only thing that I am wondering about is how to make sure that there are 4 contacts (without opening up the cable)? Up until this point, I thought that the plug determined if it is balanced or not… In my mind it was: SE = 3.5 mm/6.3 mm and balanced = 2.5 mm, 4.4 mm, and XLR. But it seems like I got it all quite wrong

This is a balanced 3.5mm connector - goes into the amp
Note it has 4 points of electrical contact not 3
image

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isn’t there a relational order of operations that needs to be understood?

For example you can run a hp balanced cable out of a SE output of an amp using say a Xlr -> 3.5mm adapter.

But you shouldn’t run an unbalanced hp cable out of a balanced amp output correct?

So it makes sense for versatility to have a balanced cable that can run from both balanced and unbalanced amp outputs to provide the maximum usability?

Maybe I’m screwing up the actual points but you get what I’m trying to infer…

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Yes and no. The confusion is understandable. For whatever reason, “industry standards” have made the vast majority of 3.5mm and 6.3mm connectors SE and 2.5mm, 4.4mm, and XLR balanced. But as @Polygonhell just showed, there are 3.5mm balanced TRRS connectors out there. XLR being balanced is the pro audio market bleeding into the consumer market. The common divide of 3.5/6.3 being SE and 2.5/4.4 being balanced just kinda happened by unofficial agreement, I think.

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Damn… didn’t know they existed. Well, it’s time to educate myself. This is why you said that there would be a problem sticking SE to a balanced amp. This would be the case if you plugged an unbalanced 3.5 mm into a balanced amp with a 3.5 mm output, correct?

Also curious about this… Is there any advantage at all of using a bal cable + SE jack, versus just using SE cable w/SE jack? Does the bal cable eliminate any noise? Or only in a fully balanced connection…?

Short version is no.
The slightly longer version is it depends how much you believe headphone cables can affect sound and the quality of the various cables, connectors and adapters.

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Gotcha lol. TY!

Now, I have an unusual question.

If a headphone has a USB-C connector on the headphone end, can the cable be balanced?

My limited-knowledged self would assume the answer is no — but then, I have no technical understanding of a USB-C connector, especially when it comes to audio use.

Would it make a difference if there were two USB-C connectors (one on each ear-cup) — that is, if it’s even possible to use two USB-C connectors.

USB-C 3.1 is in question.

Yea sure it can, but the real question is why would they want to design it as a balanced one?

From your description, I would assume that the headphone is connected to the computer and receive a digital signal from the USB. Then, the digital to analog conversion would be done on the USB, like the picture below. And from there, the designer can freely choose whether they want to make a balanced circuit inside it or a single ended one. Now the question is why would they want to make a balanced circuit when they can do it in a single ended one with less hassle.

41lorPgNk9L

There might be a timing problem if the USB that’s said is receiving digital signal, but since it’s a headphone maybe no one would notice. But again, if it’s digital you can do it from one and have the DAC in balanced.

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So basically the USB-C would have a DAC implemented in it? The manufacturer mentioned that this would be implemented in the future (DAC+Amp)

The reason why I’m asking is because a high-end headphone (Binom-ER — ~5k euros) is using a USB-C connnector. It is a planar-magnetic headphone, so I’m assuming people would want to use their desktop flagship DACs and Amps. Could they do that if the connector on the headphone end is a USB-C?

I’m still not sure what connector is being used on the amp end…

As to why a USB-C is being used, it comes to the fact that the ear-cups are insanely slim. Apparently the standard connectors would require increase in thickness or something along those lines.

It could just be they are using the connector, rather than it actually being a USB-C connection, there are more than enough wires on a USB-C connector to wire it balanced (24 I think).
Some DAC’s use HDMI connectors or RJ45 for I2C make them video ports or network ports, just a convenient electrical connection, you can buy off the shelf in quantity.
You’d have to ask the manufacturer.

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Ah IC. Hmm what if the headphone is actually just using it to carry the analog signal, not like what I just said. Maybe they use it like 4 pin xlr → usb c, where the usb c is for the headphone only for the sake of being thin. Because usually the DAC that’s used in a dongle DAC or USB C headphones are quite weak and this being a planar must need a lot of power.

Edit: Just like what @Polygonhell said.

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