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Line-out ≠ Headphone-out
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- เผยแพร่เมื่อ 18 พ.ย. 2022
- A video to explain why a line output is not the same thing as a headphone output.
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I think the whole "line out can be used for headphones" comes mainly from PCs, where line out and headphones were often coming off the same audio amplifier chipset, and were both volume controlled in software.
Also, every Realtek chip (which are in like 95% of motherboards) has switchable pinout. That means, you can change pinout in software to be headphone output, line output, line input, microphone input, rear-surround-output or whatever you like (until it allows for such combination).
You can actually do pretty wild stuff with this when I was tinkering with it on Linux years ago. No Windows (and even Linux) software had all the possibilities, but with OSS (Open Sound System) audio service (instead of traditional ALSA) it was actually possible to change pinout of anything.
@@morsikplwhy do they call mother boards motherboards???
👉 I DON'T KNOW.
@@destructodisk9074
Hey. What do people call box turtles, "box turtles" ?
👉 I DON'T KNOW 😎
@@That-Ninja I call 'em mainboards
@@sf4137 whoa there.
Desktop pc sound cards have a socket labeled line out and you can plug in headphones into that, sound card detects the impedance of what’s been connected and adjusts levels appropriately. This may be the source of confusion.
I was just about to write the same thing and then saw your comment. The sound I/O chip definitely does that in most PCs. In some cases they even ask you to confirm what you just plugged in.
@Google user It detects when something is plugged in and asks the user what was plugged in. Modern combo jacks can be a line in, line out, microphone in, headphone out or two way headset using a switching circuit in the audio chip.
Some modern motherboards with integrated sound i/o also have a plug labeled line out that's more than suitable for headphones in my experience, which could also lead to believing any line out can be used for headphones with no issue.
Dell Optiplex always detects if have plugged in headphones or speakers, although I need to choose, cause the sound card thinks my headphones are speakers probably because of the larger impedance
@Google user I've not seen commodity audio chips auto detect impedance personally - So I can't corroborate that. Apple says their high impedance compatible jack does auto-detect using impedance measurement though, it's quite unique as far as I understand. It's also more about providing more voltage for high impedance headphones rather than switching between line and headphone levels.
I think another thing that is confusing in this discussion is that many modern devices either combine line out and headphone out, or have line out that is “amplified”, but have no volume control
Especially those very popular devices we almost all have - laptops. And similar devices that are "smart" and can switch the mode of the jack.
Also no one uses wired headphones anymore
@@MikehMike01 Anyone serious about their audio uses wired headphones.
@@MikehMike01 Is that a joke? Or do you actually believe that?
Yeah, even a lot of (cheaper) music instruments don't have dedicated line out jacks anymore, but only headphone jacks. All the Korg Volca synthesizers for example (they also have 3.5mm jacks for CV sync and some of them also 3.5mm MIDI, to further confuse the 'they are the same connector' people).
As an audio engineer for the better part of 30 years (and an all-round nerd for much longer) I often find myself explaining the finer points of interconnect standards to normal folk with glazed eyes who couldn't care less and just want the thing to make the sound. I have to remind myself that there are far more walks in life about which I'm ignorant than there are in which I am expert.
Not your fault. Theirs. Unless you really deep dive into the topic, and go overboard, if they want their stuff to work, and enjoy, they'll have to learn. When they do so, just go: do you care about knowing the difference of those pedals in your car or you just push them randomly and hope for the best? ;) Ignorance is only excused at birth, after that, one can learn.
Your last sentence does not let the idiots who come in with their ignorant advice and who then get mad when you call them out as being wrong even though they cannot justify where they got their information from. I do agree that I am far from an expert in many things but I keep an open mind and accept being corrected.
I can relate well to the public ignorance and inability to shut up when they are clearly out of their knowledge zone. 90% of my job is highly specialized to the point that the average public literally doesn't know what I do is a thing that even exists. Still doesn't stop them from trying to tell me how to do my job anyway.
@@OttawaOldFart doesn't let them what
@@OttawaOldFart The worst is when I fix something for somebody and they blame me for a completely different, unrelated issue. "You got my WiFi working a week ago but now my printer prints streaks all over the paper. WHAT DID YOU DO?!?" They suddenly become computer experts the moment something goes wrong.
I stopped giving tech support to family members for this very reason.
Funny thing, I once had a CD player in the military that I left at the squadron one day. My buddy took it apart and soldered the headphones and Line Out wrong. When I got it the next day I couldn't figure out why it was so quiet, so I plugged it into the Line Out and it worked great. A few days later he told me what he did.
Started telling people that it was a rare CD player because they mislabeled it. A lot of the new guys actually believed it.
Your boddy goes a long way for a prank.
@@schwarzerritter5724 That was pretty usual. I've spent weeks on a prank before. Plus, this was deployed, so he had a lot of free time.
Your story was going good until that last part. I mean unless all of the people you knew were tinkers or music buffs. Normal people have no freaking clue there's a difference between line out and headphone jack.
@@MamaMOB You're somewhat right. Most people don't know.
The buddy who did the modification prank was also a part time DJ and liked to tinker with his equipment. So he knew.
The rest were mainly because of our job. We would make patch cables to hook up CD players to the aircrafts ICS so we could listen to tunes while cruising around. It was a big thing until big Air Force got involved and actually banned it.
The thing is, the ICS for the C-130 was still using 1950's tech, so was actually kinda fragile. You had to use line out. If your CD players headphone jack had any kind of boost or amplification it could cause damage to the aircraft (Hence why it was eventually banned period). So you learned the difference between the two pretty quick if you wanted to play music on a flight. Anytime someone was hooking up for music, at least one member of the crew was making sure you used line out.
@@Plaprad Ok you lost me there at "could do damage to the aircraft." You need to come up with a better story next time.
as a musician and audio engineer, this video is hilariously necessary for the music consuming public
It really is. I'm by no means either an audiophile nor a technology expert. But I like to think that I'm at least reasonably knowledgeable in both areas, and I kind of just always assumed that a 3.5 mm line-out was usable as a 3.5 mm headphone out. Good to know that that's not the case.
work with this stuff a bit, but his description of why line out is the same (switching between equipment) made the next level of it click in my head lol
@@scaper8 honestly you still can use either as a headphone amplifier but normally the line out will have half or even less dB of the signal, so that's why it's so quiet. it's a use of last resort if you have nothing else to listen with!
The fun thing (which probably makes the average user more confused) is that the fact that if a line output is connected to the line input of another device, it usually gives similar input levels to that device as a headphone output will do at full volume. That's because the thing is mostly just about the impedances. Voltage levels of both type of outputs are about the same, so with a high impedance line input (that barely put any load on the signal), they give similar levels.
But, if headphones are connected to the line output signal, the voltage level will plummet - because that output can't supply much current (high output impedance).
The amplifier circuit in the headphone output on the other hand, can supply much more current to the signal (low output impedance), so the signal level don't drop as much under load.
@@Speeder84XL BOOOM nothing better than the actual engineering explanation
Thanks so much for taking the time to clear this up! For those of you who want to jump to why line out is not the same thing as a headphone jack -
Purpose of line out 4:18
How to use a headphone amplifier to amplify the line out 8:15
Love the 8-Bit Guy Retro Grooves crossover btw.
This is such a great channel. Always such interesting stuff and the production is top notch. Keep up the awesome work.
As you stated, a main source of confusion is that in practice, headphone outputs are often used as line outputs. Many a laptop or phone has been connected to an amplifier or powered speaker system by using the headphone output to feed the line input of the amplifier. Judicious use of the source device's volume control can give an appropriate signal level at the headphone output. Output impedance is really the issue here. Headphone outputs are low source impedance outputs while a line out is typically a high source impedance output (and as you say, line outs don't typically have a volume/level control). So a headphone output can do a passable job of providing a line output function, but a line output cannot drive most headphones.
A note to add to this... My Asus laptop, the headphone jack can also be used as an actual line out, as when I plug something into the jack, my laptop with clarify first, whether I plugged in a line device or headphones, and upon selection, it will adjust the impedance and audio levels accordingly. Which is very cool! 🙂
@@jinky0u812 Was just going to say this, as a high proportion of PC desktop motherboards built in audio will allow you to change on the fly what the 3.5m inputs/outputs can be used as. So I imagine this has caused a fair bit of confusion.
Not to mention that Realtek's ALC sound card chip allows to change pins purpose on-the-fly. So your jack connection can be either mic input, line input, line output or headphone output at the same time depending on settings ;)
is it anyhow harmful to the laptop if i connect it with a speaker system with subwoofer and 5 speakers??
This is the actual answer. I just spent 5 mins listening to half accurate bullshit watching the video itself, which presents things as if headphones can never be plugged into the line out port, but the truth is the often are and work just fine, and there is no other option anyway on many devices.
I like that the headphone amplifier looks like a little whiskey flask.
Now you mention it, it does. I’ve never thought about it before.
It does!
@@Techmoan a lot of the early radio mics used a hip flask as a case
whiskey amplifier !
It wouldn't hold enough whisky 🥃🤣
After doing some restoration research and finding mostly useless videos with no editing, coming back to techmoan to relax is a welcome change of pace. Your videos are so well recorded, edited, and informative, thank you for your efforts
This is a great video, I've always wondered this myself!
A lot of the confusion comes from PC because the audio volume is always controlled manually on windows.
yes, because on the PC you use the line in/out and the computer's sound card will handle the amplifying. and plugging in a headphone into the headphone will mute the line out. which i guess is the difference of line out and headphone on a pc...the override.
Not always! Some CD drives had volume knobs on them.
@@moonrazk those old CD drives had a cable in the back that went to the sound card. In software the CD playback would get its own mixer control. For all i know it might still work that way, but I haven't played CD audio that way since before 2000 or so. After that I would use cdda2wav or cdparanoia and rip
it's still confusing. -_-
laptops have a switching mechanism inside. Headphones have much much higher impedance than line signals and the jack on the laptop can detect that and use software to switch the headphone amp in and out of circuit. Older laptops used to have both jacks on like all other equipment but with the software switching now it is combined into one. but both are still technically in there. easy to be confused when you only see one physical jack.
I think the concept is slightly blurred for a lot of people due to quite a few devices out there which have an output labelled as a shared headphone and line out socket, which is of course usually just a normal headphone output. Also nice to know someone else is enjoying Philips Fidelios!
Agree!
As soon as I saw him get them out I thought "I know thise headphones, I have a pair myself".
Thanks, this was helpful.
Not blurred for me. Its really very simple.
My line 6 spider V guitar amp has a USB out(truly a great feature) and a cheap little headphones/line out 1/8 that says the same thing. Still not very clear
Until now, I really thought Line Out was the same as Headphone out. Very informative. Thank you as always, Techmoan!
On anything modern it is. Impedance is adjusted based on whats plugged in.
You thought, but you weren't sure... I don't imagine that you'd confidently state that they are the same though to correct someone else?
@@gavincraddock5772 What's the point of this comment... ? Why do you care?
i am experienced with electronics but not an audiophile. I always thought of line out as "speaker but you can't raise the volume". this video is helpful to know more detail on that
@@Wylie288 no, he just explained why it isn't.
Thank you for this video. I work in IT and dabble in audio a bit - the amount of times I have had to try to explain this difference to others has been an exercise in frustration. I'll be sending them your video from here on out :D
I did not know that! Thank you for showing it. This does explain some of the issues I've had in the past! Most PCs have a line out-headphone hybrid though
You are the first person that has managed to finally, at long bloody last, explain to me the whole concept of Line Level in clear and simple way. Many, many thanks for that. You may want to look into explaining other similar equipment intricacies, you are pretty satisfyingly good at it.
Another difference to consider is that the circuitry for creating a line output is designed to only provide just enough power to convey the signal from one device to another. They aren't meant to provide the power required to physically move a speaker/headphone diaphragm. And doing so could potentially damage or destroy the line output of a device, as it is being asked to provide a lot more power than it was designed for.
Related to that is the impedance mismatch. Consumer line outputs are meant to drive a load of roughly 10,000 ohms. Headphones are typically less than 100 ohms. Not only does this mean that it takes more power to drive the headphones than a line input, it also means that the frequency response is going to be all wrong. When headphones are plugged into a line output, not only will it be quiet, and you could be damaging the circuitry, it's also going to sound bad -- usually seriously lacking in bass, overemphasizing higher frequencies.
You can usually get away with going the other way (headphone output into line output) because it's easier to drive a higher impedance load than a lower impedance load, so headphone amplifiers can easily output the power required by a line input. Sort of like asking a sports car to idle down the street. But the impedance mismatch is still there, and it could result (depending on how the circuitry is designed) in bass frequencies being over emphasized. The other issue there is that headphone amplifiers, because they are primarily designed to provide more power rather than a cleaner signal, are often rather noisy (mostly in the form of hiss) compared to a true line output.
The best thing to do is make sure that whatever load (headphones, line input, whatever) you're driving matches what the circuitry in the output is designed to handle. Anything else can result in poor quality sound at best, and damage or destruction at worst.
"it is being asked to provide a lot more power than it was designed for" How does that work? It gives what it gives and the speakers react to what they get. Headphones are generally a passive device, aren't they?
Yes, headphones are passive devices, just like light bulbs. So how does a wall socket know how much current to put into a light bulb? Well, it doesn't, but it has a given AC voltage, and the resistance of the load determines the amount of power delivered. A fork has a much lower resistance than a light bulb, which explains why it would instantly blow a fuse (or set your house on fire) if plugged into a wall socket.
@@romulusnr Impedance, which is a fancy way of saying "AC ohms". In a classic circuit with a power source and a resistor, P=IE and E=IR, where E is volts, I is amps, R is ohms, and P is watts. So, if you take a 1 volt battery and use a 10 ohm load, 1 = I* 10, I = 0.1. The battery is asked to give 100 milliamps. If it can't, the voltage will fall. Well, Impedance
is the same animal only it's for AC - like you have speakers, which often will measure as less than a ohm to DC (and will burn out if connected to DC of any reasonable source) but present as 8 ohms to a AC source.
Now, a well designed line out driver will be designed so that you can direct-short it and it doesn't hurt it, because realistically, 3.5mm plugs will do that at times. It will also be designed so you can connect it to a headphone output and it won't hurt it, because inevitably some idiot - or person who can't see the label - will do that. You're not going to hurt a line out by hooking it to a speaker load if the designer knew what they were doing. But it also isn't going to drive headphones acceptably
@@jonathanpullen7439 You're presuming they know what they are doing. That's why it's not recommended to plug headphones, there is no standard when it comes to line-in.
@@romulusnr The line driver which is designed to provide a high fidelity signal into a 10,000 ohm load of a line level input is not designed to drive a 32 ohm headphone. The amount of power the driver is TASKED TO PROVIDE is a function of the impedance being driven.
Stuff like this is exactly why I subscribed years ago. Good to hear a good techmoan moan
OMG I loved that stylish Walkman cassette player! Imagine those back in the day haha. I already knew all this but I was just interested in your equipment as I always loved EQ's, VU meters, plugs and wires and having the option to literally fine tune your music from any frequency or amplification! I used to install sound systems in cars and the odd home theater but, it's not the same as everything is wireless and hidden. Car stereo setups are exactly the same. Hook up a sub to the dedicated RCA line out and there is nothing. It was quite amazing how many people asked the same question that you are answering now. Great video and very detailed! Thanks.
What was that Walkman cassette player - was that an image of a cassette on a screen???
I worked at Radio Shack in the late 70's, and I must have explained all this a hundred times to people in the store! Good video and explanation on it.
The amplification on a Headphones output is Current based (amps) rather than the Voltage based level for Line Out. The circuitry is 'high impedance' for line out (can be thought of as having the volume pot set to low) therefore does not supply enough current to drive magnetic headphones. You would probably find old piezo headphones would work much better because of their low current demand. This would still not resolve the need for variable volume of course unless the headphones had an integrated pot. EDIT - For clarification, Headphone Output = Low impedance ( eg 8 or 16 ohms), Line Out = High Impedance ( could be 1000s of Ohms).
the last stage of power amplifiers often have little or no gain, they're just there to handle the big currents required and match the impedance of the speaker you're driving. kind of like a small current of 100mA can activate a relay that can control 10 or 20 amps.
I looks like some devices support using headphone out as line out and some don't... I used to have a Philips portable CD player which the manual stated that you can use hp out as line out if the volume control is set to 8.
@@gctechs Devices (such as Amplifiers) that would connect to Line Out only need (and expect) a High Impedance signal, so it is all about how much the voltage changes over time. As such, as long as a low impedance source such as a Headphone output has enough 'volts' (even though it's really modulating Current/Power) a device such as an amplifier will typically still get enough signal to be able to amplify it to the user's needs (there are some circuit designs for headphone outputs that might not work with a high impedance 'receiver' but I think these will be rare).
@@SardiPax is that why some things I plugged from the headphone socket were quieter than the Line Out. Even when the volume was maxed out.
My old amp was expecting a higher impedance?
@@SardiPax A voltage amplifier, which is the only kind used for sound reproduction, will never amplify current. they are just able to supply a larger current whilst maintaining a constant voltage gain. Think about it as what is being controlled by the amplifier. Also "modulating" refers to a completely different process.
Nice Video. As "IT- Guy" I always get into the same problem with USB C. Most people think USB C is automaticly USB 3.0 or higher but that not the case. The one thing is the way it is build: TRS (Tip Ring Socket) or TRRS (second Ring often used for Microfon) known as Audio Jack and "Line In" or "Headphone" Jack is the technic behind it on the other Side. I mean USB C is the same connector like Thunderbold but it is almost never compatible flawless with USB 3.2 Gen 2 and so on...
I'm not surprised, I often see USB-C referred to as being USB 3 in ignorant articles as computers with USB-C ports tend to also have USB 3 ports (which are USB-A). I have quite a few portable devices that use USB-C as it's a more durable connector that can handle more power for faster charging but they don't transfer data any faster than USB 2 speeds as the speed is limited by the onboard flash memory speed.
You have a shockingly good mic! I swear I could hear the percussion engraved on that vinyl even before you turned on the amp.
When I was at college, and poor, I bought a pair of ear phones from Poundland (back when everything was £1) and used to use them as a microphone for talking to friends on MSN. Wasn’t great quality, but it worked.
I remember plugging in an old dynamic ? well i am sure it was as it was supplied with 2 for an old stereo my parents had. well anyway for shits and giggles i plugged it into the earphone of my little cassette recorder and it works as you may guess but not well. It had a tinny tweeter like sound.
I did it the other way once. My nan used to have a really early compact cassette recorder which came with its own microphone in a leather carry case and as a kid I was fascinated to find if I plugged the mike into the headphone socket you could get sound to come out. Unfortunately that sound was mum Nan's Singalongamax cassettes but you can't have everything.
@@steviebboy69 An old DJ friend of mine lost his headphones and used his mic to cue everything up for a while. It was a bit difficult in a club setting, but he managed.
Back in the early '70s I had an Amphenol Commander 750 CB radio. The hand-held microphone on a coiled cord used a permanent magnet speaker as both speaker and microphone, there was no speaker in the main unit. Funny thing, I installed a 3.5mm (1/8-inch) jack in the microphone, wired so I could plug in an external speaker yet still use the built-in one as the mic.
@@steve.b.23 he held a mic up to his ear? Lol must have looked silly
I love that Techmoan takes the time to educate us on stuff like this, especially when there's no guarantee a video about line-out vs headphone jack will be popular/bring in a lot of ad views.
Great commitment with the channel! Love it
I have had some headphones that can be used in Line-out (according to their packaging), they have volume control on their cord. But I am thankful you explained this because now it makes a lot of sense!
Is that volume control self-contained? Or does it just send signals to the audio source device, commanding it to change its output volume? (For example, the volume buttons on Apple's EarPods simply tell the iPhone/iPod they're plugged into to raise or lower its output volume.)
They have built in amplifiers. There is no way to send volume control through the 3.5mm jack.
As for the earpods, well, that's bluetooth. (And earpods must generate the analog signal anyway)
@@Ryndae-l they were talking about the older wired earpods, which sent a signal to the phone via the mic part of the connector, which the phone interpreted as a volume control/play/pause command
They are either headphones with a built-in amplifier or they are high impedance like the ones used with valve radios and crystal radios.
@@Ryndae-l There is a way to send volume control commands through 3.5mm. Idk if you've just forgot or are genuinely just too young to know about this, but just about every pair of 3.5mm earbuds used to have inline volume and playpause controls. You can do this by sending a signal over the mic part of a combo jack, which is, I believe, mostly a standardized protocol in terms of which tones to use for which button. Volume up, down, play, pause, skip track, previous track and fast forward are all possible using this trick by using the inline volume buttons or pressing the playpause button in some pattern (single, double or triple click) or holding it. Apple still uses this on their wired earbuds, but they didnt invent this. Digital earbuds and headphones merely continued to use a standard that was already commonplace.
The other issue with headphones these days that might have influenced the decision to not have headphone out is back in the day headphones were often used to plug in to home audio systems and had quite a generous length of cable. Modern headphones generally have much shorter cables as they are usually designed for personal audio equipment. The impact of this is you would struggle to use modern headphones on the burger without tugging the machine every time you move or having to keep your face really close to the player.
It is just economics, nothing more.
Having a line out is much cheaper than adding an extra amplifier, volume knob, etc
The device is already extremely niche, so adding anything extra has a huge effect on returns..... cost/balances....
i don't think that's an issue if you really want to use your short cable headphones for something that requires a longer one. a simple 3,5mm extension cable with a male plug at one end and a female one at the other does the trick. that's the beauty of things like this, you can pretty much always find a way around the problem
@@CookieTube Thanks to phone makers like Apple, corded headphones (at least for portable use) seems to fading away. I think the manufacturer is just a little bit ahead of the curve, that's all.
Depends on what headphones we're talking about. Any decent hifi wired headphones would have a 6mm jack or a 3.5mm (usually a 6mm) to plug into deck amps and whatnot. If we're talking about shitty apple or bose or beats, then yeah, but nobody will listen to vinyl on those.
Sennheiser does not have that problem. Always with more than 2m (usually 2,5 m).
Like you said, the misconception comes from the fact that it’s the other way around. Before Bluetooth was so widespread there were car radios and small home hifis which had an input at the front labeled line in or aux in. Those were made to connect MP3 players or other small devices instead of other hifi equipment. Especially in the case of the car radio.
So the confusion really comes from people selling "hifi" equipment with mini jack connectors instead of RCA
Great video! More technical: Impedance mismatching between the line out and the headphones itself is causing low volume. Most of the modern headphones do have an impedance below 50 Ohms (typical 32 Ohms, but it slightly varies). To drive a 32 Ohm device, you'll need an amplifier that is at least 32 Ohms, but for a stable and predictable coupling, it's better to go way below that. In fact, a good designed headphones amplifier will have an output impedance that is 8 times lower, around 4 Ohms. And that's the issue with line level outputs. They have an output impedance of about 600 Ohms. You're literally overloading the output with headphones. It will cause a voltage drop. Line inputs tend to have a fairly high impedance of around 10kOhms. They're not able to overload a headphones output.
The first time I got in contact with line in/out vs mic/headphone was a few years ago when I had to get some audio from seperate devices recorded. Not knowing anything it was hard to search for but in the end I was able to do what I wanted.
Thanks for now providing me an answer for the why on all of this. Scratched a knowledge itch I didn't knew I had! 😄
Thanks for taking the time to set the record straight properly Techmoan. The problem with the information age is that as information has become more accessible, so has disinformation. Wise men talk because they have something to say; fools, because they have to say something.
The Dunning-Kruger effect.
Something to bear in mind with headphone out vs line is is that, in a device with built-in speakers plugging something into the headphone socket will defeat the speakers, but plugging something into the line out will not. Once needed to amplify a portable keyboard and it only had a headphone socket so with the PA speakers in front of me, no foldback and a guitarist behind with his own amp it was very hard to hear yourself playing.
Parallel outputs where Headphone and Line-out can co-exist
I had a guitar amplifier wherein the line out *did* defeat the speakers, and it's easy to see why you might want that; in a live situation, it reduces feedback. Of course your situation also exists, but I don't think that there are rock-solid rules one way or the other.
Great video! Never understood the difference and this is literally the first time I have ever found anyone explaining it
The gain selector on the headphone amplifier is intended as an easy way to accommodate both output levels as inputs: line out, high gain is needed and headphone out, low gain is adequate.
Gain is more about your headphones, than line out. Problem with using an amplified signal as line out is that it's not a standardized impedance. Don't use headphone outputs as line outs, please.
@@Septimius What you're saying is true but may be answering a different question. Headphones and wired ear buds have widely varying impedances from a few Ohms for full size headphones to well over a thousand Ohms for ear buds. That's the problem that is most easily solved with a headphone amplifier. It could be solved in many cases by an impedance matching transformer but that's for us technicians, not the typical user.
Your comment seems to be addressing the opposite problem, that of using the source, headphone or line, as an input to other devices. Sometimes a headphone output is all you have to work with and the most expedient option is a simple attenuator. We don't design this way but when the boss says to make it work for the next couple of hours and the show must go on, well…
Going into this I was wondering why this merited a video. Love why you made this video, the structure and how you seemed to hit all the points that anyone would wonder about. I legitimately think this video literally made the world a better place.
A very slow day perhaps,,,
@@mUbase 😂😂
The headphones/line-out confusion seems like it is a case of "not all rectangles are squares but all squares are rectangles". Although, this is one of the things I have wondered on older items, I figured they had to be different in SOMEway or else they'd just all "headphones/line-out" or the like.
It's more likely because on a lot of mobile devices and laptops, the mini jack output *can* function as a headphone and lineout. My old MacBook for example only has one minijack. Somehow they can detect whether it needs a lineout or headphone out signal.
The line output signal also shouldn't change with the volume setting on the playback device, unlike headphones.
@@DylanPank71 that's also because many motherboards or sound cards on PC have the capability to read the impedance level and adjust accordingly, essentially changing the line-out to a headphone jack. I'd imagine the combined output+microphone jacks phones and laptops have can do the same. so it's essentially all three of them in one, line-out/headphone + microphone
People think a hole is a hole. Having to explain to people that they can't charge their USB-C laptop with their phone charger is fun times.
@@DylanPank71 Well it could stick a signal or a voltage down and determine by the current what the load is. I think they have clever transistor switching circuits that can change whats connected.
Sir, I've been watching your videos for about 10 years & really gain the knowledge you share. It's my humble request to make videos of car Audio systems like cassette players, CD players/changers, ESP's, Ampl;ifiers, Woofers etc.
Excellent explanation, gentleman, thx for it 👍 Love ur videos 💖
Thank you for educating people on this. I feel like I’ve spent decades trying to explain this yet people still don’t seem to get it.
Thank you very much for this video! I appreciate that you know not everyone is as much of an audiophile as the majority of this channel's viewers and that basic things like this are actually not known to the average person.
It’s a useful point about using a headphone out as a line out! I use a Vox Amplug2 through a splitter to get enough signal into an iPad to be able to use the software amplifiers; the vox also works well when I want a highly portable guitar amp for practice - plugged in the back of a 20W powered speaker. It even sounds nice - nothing like an AC30 or a good Fender amp - but enough noise for a small jam session with friends, or a singaround!
The "gain Lo/Hi" is for either coming directly out of a record player at "Phono" level (Lo) or "Line" level (Hi) after it's gone through a mixer or some other piece of equipment that brings it up to Line level. Some record players may boost it to Line level now days, and this could account for the difference in levels you've experienced with different Vinyl players, however usually the vinyl player's Phono output will be some 20dbmV-30bdmV quieter than Line at a bare minimum being that Phono is normally around 0.15mV-5mV only (5mV is super high compared to the average), and Line runs at a level of up to around 300mV!. ;)
It all boils down to output impedance. Line out is typically kiloohms, headphone output is meant to handle 32...600 ohm phones. If you connect these to the line output, you not only get a very silent sound, but it'll lack in low frequencies as the output coupling capacitors combined with headphones will form a high-pass filter.
True. And conversely, some line-in devices do not get enough volume when fed from some headphone outputs. This is because a line in/out is supposed to be 1V over 10kΩ, whereas one volt over 32Ω headphones would be 31,25mW. Doesn't sound like a lot, but that's a lot more than most headphones need. Most headphones have a sensitivity of at least 100dB SPL per mW, meaning 31mW would be 115dB. That's loud enough to be bad for your ears. Many, especially small and battery powered devices don't output enough voltage for that reason and are much quieter than a hi-fi component plugged into another line input.
@@krzysztofczarnecki8238 I once plugged headphones into line out and could barely hear. So I wondered if I turned down the headphones out to match the perceived level of the line out, could I have 2 lineouts. Needless to say it didn't work. The line out was louder.
True, they differ in more than just volume. Line out is a signal, like the signal used within the device, meant to be used within another device. Headphone or speaker output is the final stage, the result of that signal after filtering, processing, or amplification, meant to be heard by the user of the device. Using either for their unintended purpose will cause you to lose information.
Input impedance, not output impedance.
A line _input_ typically has an impedance of 1-47K. The line _output_ impedance varies, might be around 100R, just to protect the output driver against a direct short.
Headphones will have an impedance of 8-700R, with typical values somewhere between 32-400R. The output should have as low impedance as possible - ideally “none,” but realistically just “less than the headphones.”
@@krzysztofczarnecki8238 Absolutely. A lot of headphone outputs on modern devices have the potential to deliver a decent current, as they might expect a 32 ohm load, but significantly less voltage, Voltage is much more important for getting a decent level into a line-in than current is. As the input will be a relatively high impedance. However, one thing you can do in this situation (if you don't want to use a pre-amp) is to use a small audio transformer to step up the voltage. Headphone outputs will drive these very well.
thanks for explanation! I've had (recently) a belief, that Line-Out was too loud for most headphones... but as I'm now reaching old memories from my childhood, I remember that this socket was always useless for using with most headphones.
1st time visiting this channel. Nice little video. Very informative.
OHHH thanks I was trying to find out the difference between line out and headphones on my computer, and I found this recommended video... NOW it all makes sense, thanks!
This takes me back. My first headphone amp was a Radio Shack kit built into one of their project boxes the size of a brick. It required two 9V batteries which it ate Pretty quickly. Sounded great though.
This also reminds me of a separate record deck. Some people think their deck is faulty when they plug their deck right into a line in…. But what you need is something called a pre-amp. So it would go…
Deck -> Pre-Amp -> Line-In - AMP
… which brings the audio from the stylus up to the correct level. Some audiophiles go as far as using tube pre-amps because it gives a warm sound. Yeah, sometimes old is better than new.
It's not just the signal level needing boosted, the EQ needs fixed too. Phonograph massively drop the bass and boost the treble so the signal fits on the disk more effectively. A phono preamp restores the signal to it's correct eq
Receivers often have a dedicated phono input that has the pre amp built in so you can just connect rhe deck directly.
Thank you for answering a question I have wondered about every time I've plugged in an audio device but never bothered to look up.
Line out gives you a line level output, which is exactly +4dBu (0dBu being 0.775V and +4dBu being 1.736V) Line level is a very important standard when professionally working with audio. Mic level is 60dB below the line level and its usually what dynamic microphones put out. -60DB is btw the same as saying 1/1000. So the output voltage will be amplified to 1000 times as much as it came in when you plug anything into the mic port (Condenser mics usually give off a much higher level and you will amplify them by something like 40dB or sometimes even less). Professional mixers usually let you set the exact gain because you rarely need the full +60dB of gain unless you are using a microphone not suited for the situation you are using it in. But you could theoretically use a preamp before the preamp. Something like a cloudlifter, which adds +20dB of gain (which is a 10 times amplification). After amplyfying the microphone the 0dB on your mixer means exactly +4dBu of level. And if you send this signal out it will peak at exactly 1.736V, which is very important as said for other devices because all devices expect 0dB to be at exactly this voltage once the input was processed. So the line out is intended to be sent to a device, which expects a standardized signal, which could be the amp for your speakers. What exactly your amps do isnt specified - every model is capable of different things. From there on the signal gets either reduced for lower loudness or increased for greater loudness.
The Headphone out has exactly this amp built in already. It takes the line level signal and increases it further. But if you dont like the built in amp, or want to plug the player into a mixer for whatever purpose you need to do that, you should use the Line out and then wont need to apply neither gain nor attenuation in the next device in the processing, chain since its already at line level - provided the music you play is normalized and the output is working, as it should.
Almost. There are TWO specs for Line Out. Professional, which you quote is "normally" +4dBu. (Some broadcasters use +8dBu and most telephone companies use 0dBu) The audio industry (like recording studios) typically settled on +4dBu and all interconnections were always balanced typified by XLR connectors.
However, the consumer equipment reference is -10bBV for "Line Out" (0.316V) and is typically unbalanced using RCA connectors. This translates to a 12db difference. (dBu is dB relative to 0.775 volts where 0dBu = 0.775 volts however dBV is dB relative to 1.0 volt where 0dBV = 1.0 volt) Cheers...
I thought it was basically that line out is not amplified in any way, hence LINE level output - it takes the signal being read by the player (whether record stylus, cassette tape head, CD's DAC, whatever) and outputs it. Versus the headphone jack that has an amplifier built in and, more importantly, a volume control
I doubt anyone professional would be working with something so cheap but you do sometimes get ports labelled "line out" that do have mollification for headphones
@@user-xg8yy7yl1d Well professionals sometimes use the cheapest tools in emergency situations. It is unusual - yes. But sometimes you are out of luck and stuff starts malfunctioning right before you really need them. Thats where the very cheapest tools come into play.
@@drfsupercenter It's line out because it's supplying the signal at a line level voltage, like -10dbV or +4 dBu. The issue is line level audio signaling expects very high input and output impedance - the output voltages are quite high relative to a microphone or phono cartridge, the voltage has been amplified, but the output can't actually move very much current, so if a line out can't drive something that needs current to function, like headphones or passive speakers.
One possible reason for the confusion is PCs. On mine the line out is the headphone jack, and it has amplification built in. All the motherboards with built in sound cards I've used for more than a decade have labelled it as line out, even though it's also meant for headphones.
This!
Good point! Most motherboards have separate line in and microphone inputs, but just a single “line out” which has a controllable amp
all the ones I've been using still label it as a headphone out.
@@xander1052 cool
@@xander1052 ok
Good thing the Sound Burger has a built in phono pre-amp or this would be a MUCH longer video (; Great video, as usual!
love this channel... very useful info!
always knew there was something that made them different but didnt know the depth, Thank you Techmoan
The lack of a volume control was almost all you needed to point out, but I think this was still an interesting video and worth making. You are good at taking a fairly unpromising topic and fleshing it out into something worth watching.
This is not always the case. Some devices have built-in line out volume adjustment (but it's rare)
@@TheExileFox That is usually a voltage gain adjustment, most commonly in predefined steps.
Yeah.... he could have explained this in 10 seconds.
TL:DW: A line out needs to be amplified.
Thanks very much for the interesting explanation and demo 😊
Thank you for that explanation. Understanding this would have saved me a lot of hassle a while back when I couldn't figure out why my laptop's "headphone" jack was so terrible.
have designed a lot of professional gear in my time. I would sometimes be asked to put an 1/8" mini stereo jack in so a tech can check for output with headphones. The line output would be 1/4" Phone XLR. Often to save space I used the same op-amps for the line and headphone outputs. As all of these outputs have a resistor in series, to eliminate the capacitive loading of the cable making the op-amp oscillate. I tried to make this as small as possible, usually 100 ohms. This worked fine as an unbalanced line out. For headphones, whether this world work depends on the impedance of the headphones. With 8 ohm or even 32 ohm ones the level would be quite low. But with ear buds with an impedance over 100 ohms then the line outs could also drive those.
My point being that whether the line out could drive headphones depends on both the series resistor the designer selects, which is not standardized, and the impedance and efficiency of the headphones/ear buds.
My point is that there is no standard. Sometimes a line out will drive headphones and sometimes it will not. The same is true for the other way. Sometimes a headphone output can serve as a line out and sometimes not.
But unless the designer was incredible stupid, using the line out for headphones or vice versa will not hurt anything.
Concur, the line out on my computer system is capable of driving my headphones, but at a level lower than the proper headphone socket. There appear to be different standards for audio equipment compared with other systems.
Thought I was going crazy. Used to have one of those portable CD players with a pair of cheap earbuds, and the line output would drive them just fine. Useful for sharing the music with someone else.
thank you for setting the record straight, mat!!
Those little headphone amps are awesome, I have the one you showed and several others. Perfect for audio odd jobs like impedance matching, signal boosting and, er, amplifying for headphones 😂
As always: nicely demonstrated! 👍
In technical terms the problem boils down to input-impedance and output-impedance (remember: impedance is the relation of voltage to current). The rule of thumb is that your output-impedance should be an order of magnitude lower that the input-impedance, so it is strong enough (voltage does not collapse due to too high current drawn) to drive it. In this case the headphones have the input-impedance (typically 16 or 32 Ohms for consumer gear and up to 600 Ohms for professional ones). Sadly, very often the output-impedance is not specified on the device or in the manual. But for RCA jacks (line level), they are roughly standardized (output: 200 to 2000 Ohms, input: 10000 to 1000000 Ohms). So you can match all kinds of Hifi components without any problems.
Well said!
Line out will have intrinsic impedance in series with whatever you plug into it, so a headphone will see only a small fraction of the output voltage. Basically it's not designed to output very much current or power. It's meant to go into the high impedance input of an amplifier.
It can work surprisingly well with really cheap cans, even if it's not meant to be used like that,
Always knew that "Line-Out" and "Headphone-Out" were different and you should use each accordingly. Before the video I thought it may have something to do with total volume but now I'm informed.
Thanks for the concise but in depth video :)
I got that difference as a kid, I can't even remember the device, but curiosity taught me that line out was super quiet and, more importantly, did not respond to the volume control at all.
I never consciuosly came into much contact with Hi-Fi equipment, amplifiers and the like, but I'm regularly driving my speakers from headhone outs, so over the years I kinda unlearned that.. thanks for the brush-up!
We could boil this down to: Line out is an output set to a standard output level, where a headphone out is intended for a variable output level. You could reduce the headphone out to the same level as a line out and at that point they are effectively producing the same signal. One thing about professional DJ mixers such as a Rane is that their headphone preamps are substantially more powerful to allow DJs to queue in loud clubs. In that sense, not all headphone outputs are the same, but all line outputs will have far less variability.
Now we need a video explaining Mic vs Line-In! 😂
Very informative. Thank you for this.
Short version: headphones is amplified while line-out is only the signal.
2:05 "The fact that something plugs in to something else doesn't mean that it's designed to go in to there." 🤔🤔🤔
Furthering confusion, sometimes line-in jacks on things are more designed to be used with headphone output rather than a line signal. For example, I have one of those Pure radios where there's no volume control on the line input - only DAB/FM has volume control (and bass/treble, for that matter). So if you use it with a line-level signal, which I have done, you end up with something louder than the volume at which I'd normally listen yet still quieter than the hardware is capable of.
What is that display with audio spectrogram?
thanks for your thorough explanation !
So many people fall in the trap of thinking if it fits it should work! As a qualified electrician I have seen some very worrying things because people think it fit so its ok. Love your videos, thanks for sharing.
Just saw a slightly newer comment ENCOURAGING people to “question what they’re told” and plug things into slots they don’t belong into as long as they fits to “experiment” with what will happen… I genuinely felt physically uncomfortable knowing that person is just out there waiting for the unlucky day to come where they set themselves or others on fire accidentally.
@@DoomKid it does happen unfortunately, I was trained as an apprentice at the electricity board as it was before privatisation and we were lucky to have access to a lot of the documents, data and photos of fatalities caused by ‘accidental electrocution’ or stupidity as it should be known. Obviously a set of headphones are a little different to household wiring but strange things happen
@@JumbleLane One million ohm resistor on each prong of a NEMA 5-15 P plug hooked to the tip and sleeve of an aux cord....allow us to introduce ourselves. This let's you record the sine wave coming out of the wall outlet. Don't try this unless you are certain that you are capable of insulating everything properly.
Similarly, line in != mic in. But I use my computer as a free mixer for my handheld gaming sometimes and either works fine. That's because you can easily change the mic gain to offset the difference in expected line level. I wouldn't try to use headphones from line out since there's no additional amplifier
Microphone input is even more complicated. Most microphones have an output that is many times smaller than 'line' (0.001V versus 1V P-P)... then there's condenser mikes that are even LOWER output, like microvolt levels, although these often have an integral preamp to raise them to standard mic levels.
I had the opposite kinda experience, plugged a guitar amp headphone out into the microphone input. The soundcard burning up was a very unique noise I don't want to ever recreate again
older desktops have line in, some have both in the same port, realtek will ask what did you plug in, recent laptops don't even have mic in anymore
@@namesurname4666 Older desktops? Most motherboards will have this.
Also a mic out port usually has a DC offset to power the mic itself. On a PC you can change what port does what but in a usual Hi-fi system you won't get any sound at all if you plug a microphone into a line in port (unless it has a preamplifier of course)
running a bar, I have to explain and fix this with so many people; various staff, party organisers, rubbish DJs etc. this is gonna help me teach em, thanks
Never really thought about it, but this was very informative.
You tell them Techmoan! Setting straight the 'know it alls'
Thank you for educating another generations about the subtle nuances of audio electronics!
I had no idea. Thanks for this clarification!
Thank you very much for the explanation.
Very well done Video Matt.
40 some years ago in My early Years I had some one give Me an RCA to 3.5mm patch cord they said was no good and was just gonna toss it. Me being the inquisitive person I still am with trouble shooting, Found it to have Resisters in the 3.5 Plug body. It was used for connecting to an "Headphone" out to a Line in. I still have it and use it occasionally .
Mike M.
Years ago, my family bought a Phillips N-2205 cassette recorder that came with a special patch cord. The cord had a DIN plug on one end that fit a socket on the recorder, the other end had two RCA plugs. One of the lines had a resistor in the body of the DIN plug, the other did not. As I recall, one was an input and the other was an output. But the cord could have been easily mistaken for a stereo RCA to DIN cord.
As a DJ, if we ever forgot a mic during a gig we would plug our headphones into the mic input and just use our headphones as microphones. It always blew my mind how that would work at all
Makes sense, they're basically the same principle
Yeah, I often used to use small speakers as microphones. A speaker is essentially exactly the same as a moving coil microphone (usually called a "dymanic" microphone). You can actually use a moving-coil microphone as a speaker too (at very low volumes obviously). A lot of two-way radios use the speaker as the microphone when transmitting.
Good video - thanks for sharing! Perhaps you should also cover impedance mismatch... using a headphone output into a line-in (on anything) can potentially affect frequency response.
Professional audio engineer for 10+ years now. Thank you. Just thank you 😂.
Well done. A very clear and easy to understand why it’s called LINE Out.
I have a Sony MZR-50 where the line out was about the mid-level of the headphone out. So it worked in a pinch with the headphones I had at the time when a couple people wanted to listen at the same time.
I have done this as well. It works depending on your headphones. It's not ideal but it can work.
Glad I watched it all before commenting, because my immediate thought was "pocket amp".
I have one I use with my Walkman D6C, and it's great.
I was looking at a Line Out when, as if by providence your video appeared. Thanks for preventing me from me from bying a Line Out for headphones mate.
@Techmoan - Mat, while I'd never use bluetooth for vinyl at home, I think for the intended use of a soundburger it makes sense. The big problem for me is Audio Technica only specified the SBC codec. SBC really does not sound good. If they had specified AAC, APTX and (ideally) LDAC, it would have been a perfect device for its intended purpose. As it is, bit of a letdown.
But if you're gonna use bluetooth, why even bother using vinyl at all? Just download a high quality version or use some hifi streaming service. Hell, even spotify'll do the trick. It's not like vinyl + some sh*tty analog-to-digital converter is gonna sound better. Seems like a pointless product for the intended use case
@@Supreme_Lobster depends. If you want to use it for checking used records before purchase, I'd say the ease of use of BT outweighs the negatives.
Ideally of course, it would include both. As I say, I'd never dream of BT for vinyl at home.
Fiio headphone amplifiers are great I had one when I used to rock my ipod with audio technica headphones that needed amplification. Great stuff Matt. I could tell you were a bit annoyed at those silly people misinforming others.
actually learned something here. cheers mate
I've learned this from old PC sound cards, when they had separate jack outputs and inputs for line out, line in, mic, and headphones... And also had a volume wheel!
If for some reason, you still confused after watching this then: Line out is just a headphone out but waaaaaaaaaaaaaaay quieter. So if you plug your (non-powered: no headphone amp built-in) headphone into Line out, you will probably can't hear anything or barely hear even if you turn every volume knob to the max. So.... Line-out ≠ Headphone-out.
Given how often it comes up, and the fact it's technically audio equipment, I'm surprised you haven't acquired one of those headphone testing rigs, with the manequin head, yet ;D
Came here through recommended and learned something new. I always (for as long as I can remember) knew that the line-out and headphone outputs had the same data on them, but now I know why line-out isn't a replacement for a headphone output.
This cleared up all misconception up that I had about line and headphone levels. I was always worried about blowing up somethin when using headphone outs into line-level devices. Just turn down the gain and I should be fine. Thanks.
Amps and DJ mixers have separate inputs for Line In and Phono In because the line output from analog records is lower than other line level (like CD players). Since this is a record player, I wonder if it's really "plain" Line level or the quieter Phono level.