Please don't tell me this has already been discussed, because the first thing I did was doing a search with this exact question.
Is it possible and how it's done, through DIY, to convert a regular unbalanced headphone or earphone to balanced?
So I made a search, and went to have a look on how it's done on balanced microphones and on balanced headphones.
It seems the ground is floating on both cases and you three wires for each transducer: positive, negative and floating ground. The key is to keep all these three separate all the time.
This interest arose because I bought a Fiio Headphone Amp, and it has a balanced output. So I would like to listen to it, not willing to buy a new headphone for that, just re-wiring one onto balanced output.
Has anyone re-wired their units?
Is it possible and how it's done, through DIY, to convert a regular unbalanced headphone or earphone to balanced?
So I made a search, and went to have a look on how it's done on balanced microphones and on balanced headphones.
It seems the ground is floating on both cases and you three wires for each transducer: positive, negative and floating ground. The key is to keep all these three separate all the time.
This interest arose because I bought a Fiio Headphone Amp, and it has a balanced output. So I would like to listen to it, not willing to buy a new headphone for that, just re-wiring one onto balanced output.
Has anyone re-wired their units?
Attachments
Do you know how your headphones are wired? Any 'normal' headphone?
Headphones do not need a ground.
Headphones are un-like microphones in that L and R are handled on (normally) a single connector. Each ear has two leads but the connector Koss picked is three contacts. So something has to be shared between channels.
In most headphones this shared contact leads to a shared wire all the way to the first ear. An unbal conversion means replacing this wire and grubbing around inside that ear-cup.
Headphones do not need a ground.
Headphones are un-like microphones in that L and R are handled on (normally) a single connector. Each ear has two leads but the connector Koss picked is three contacts. So something has to be shared between channels.
In most headphones this shared contact leads to a shared wire all the way to the first ear. An unbal conversion means replacing this wire and grubbing around inside that ear-cup.
I'd get an unbalanced amplifier and return or sell the other one. It's just not worth it to possibly
damage and kludge your headphones, even if they are inexpensive.
damage and kludge your headphones, even if they are inexpensive.
Yes, I know how a headphone is wired, as I know how a microphone is wired. That's why I put them together.
How is it different a headphone transducer from a microphone transducer.
Headphones do not need ground in unbalanced setups. Look at the diagram.
You're wrong. Yes, headphones have separate transducers, each of them very much like a microphone, and as a transducer you can wire them like a balanced mic. For unbalancing you connect the + or - end to ground, affecting only phase. That has been the usual wiring way for headphones since I know them. Wired lots of them to 1/4"and 1/8" plugs. Now they are using 4-pin XLRs, or better 5-pin, to wire balanced microphones to balanced outputs.
Of course I wouldn't connect a rewired headphone to a unbalanced amplifier. I have to have chip that converts the unbalanced input to balanced, and then use separate wires for the + and - wires that go into the headphone. Will probably need another active stage or a transformer between the amplifier and the phone.
What else is needed?
How is it different a headphone transducer from a microphone transducer.
Headphones do not need ground in unbalanced setups. Look at the diagram.
You're wrong. Yes, headphones have separate transducers, each of them very much like a microphone, and as a transducer you can wire them like a balanced mic. For unbalancing you connect the + or - end to ground, affecting only phase. That has been the usual wiring way for headphones since I know them. Wired lots of them to 1/4"and 1/8" plugs. Now they are using 4-pin XLRs, or better 5-pin, to wire balanced microphones to balanced outputs.
Of course I wouldn't connect a rewired headphone to a unbalanced amplifier. I have to have chip that converts the unbalanced input to balanced, and then use separate wires for the + and - wires that go into the headphone. Will probably need another active stage or a transformer between the amplifier and the phone.
What else is needed?
While microphones have three connections (+/-/shield), so called balanced headphones only require two connections per transducers (+/-). They don't really need a shield to prevent noise as they deal with bigger signals than microphones and are driven from a low impedance. Hence the 4-pins XLR.
It is better to stop comparing headphones to microphones, they are more similar to speakers. Balanced headphones are simply headphones that expose all four leads coming from the transducers (L+/L-, R+/R-), rather than joining R- and L-. It is kind of a misnomer to call these "balanced" headphones, they rather are headphones which are compatible with balanced amplifiers. Historically, when balanced amps for headphones appeared, they were mostly bridged amplifiers (with no common return allowed).
See the addendum at the bottom here: https://headwizememorial.wordpress.com/2018/03/11/a-pure-class-a-dynamic-headphone-amplifier/ It is pretty much where all this balanced headphones craze started.
PS: you'd better try to understand what PRR says. He has been a reference in the headphones DIY community for more than 20 years.
You are certainly not bothering me: far from that.
I am thankful that anyone takes the time to write a comment to my question, and if I'm wrong on my assumptions I want to know where.
Perhaps the proper answer to your comment should have been: I think you are wrong. And ask where my reasoning is not the correct one. Please do forgive my my attitude, because it's me who is wrong.
Ok, your answer does make sense on headphones levels being higher and less prone to noise than microphones. I still would like to try three wires per side, one left floating on the driver's side and listen to that, if there's any kind of difference.
In fact, in Kelvin's Grado wiring he comments this: the ground sleeve IS connected to ground in the headphone jacks only (actually decreases the noise level a bit).
Kevin's amp has few constructions issues to deal with:
1) Uses difficult to find and/or expensive dual complementary FETs at the input.
2) Proposes matching all complementary transistors (expensive and difficult to achieve).
Of course there must be many high quality balanced headphone IC based preamps around introduced since Kelvin's presentation, and I would love some suggestions from you all.
But I think I said that right now I do have a balanced headphone output on my Fiio BTR5. Apparently it looks like a question of re-wiring the jack end of some of the units I wish to try. I have a few Sony 7506 where I can do that, and immediately compare to an unbalanced one.
The smallish balanced connector I will have to find.
Do you think just rewiring the headphones would get me balanced headphones? Or there's something I'm missing.
Obviously you never saw electrostatic headphones...99.99%of them are balanced, same as their amplifiers...
Yes, just rewiring is all there is to it. Beware that headphones are usually wired in two different ways. Either they have two wires from each transducer to plug where they are joined. In this case, it's easy, just change the plug. Or the negative terminals of the transducers are joined at the headphones cups and three wires are run to the plug. Then some surgery might be required to cut that link. It's not uncommon when the cable goes to only one side.
Beware that if you have a grounded shield around the signal wires, it can make the y split a bit tricky to diy.
PS: Electrostatic headphones are completely different animals outside the scope of the question.
Edit: in general, balanced amplifiers do not bring any benefits. It's just a way to extract more power for the same voltage rails. Crosstalk might be improved a bit but this could be done with a dual mono amp (which requires the same headphones rewiring).
Beware that if you have a grounded shield around the signal wires, it can make the y split a bit tricky to diy.
PS: Electrostatic headphones are completely different animals outside the scope of the question.
Edit: in general, balanced amplifiers do not bring any benefits. It's just a way to extract more power for the same voltage rails. Crosstalk might be improved a bit but this could be done with a dual mono amp (which requires the same headphones rewiring).
WHY? Because some snake oil WEB or blog say it does something magical? It is a fad to get people to buy more expensive cans. Or are you listening in some horrible electrically noisy environment, next to an arc, maybe sitting on top of a transformer? Are your headphone cables 50 feet long? OK. maybe.
The LAST thing you want in headphones is perfect channel isolation.
The LAST thing you want in headphones is perfect channel isolation.
Do not confuse balanced amplifiers with balanced IO. Be concerned with the result, not what topology got you there.
OP mentioned his head amp has a balanced output so was thinking rewiring his dynamic cans would give him some magical improvement.. Maybe some amps have crap for SE and better balanced outputs. Can't speak for that. I would bet most of them is just the plug.
ES cans come with their proprietary amp/transformer.
Not confusing them. A bridged amplifier is a balanced amp, though not a good one (too noisy and increases THD). But there are separate amplifiers for the + and - loudspeaker pins.
Right now there several single to balanced line level ICs that are considered quite good, like those from THAT. You use two of them, one for each channel, and output to two headphone amps each, respectively connecting each one for + and -.
I am just curious to see if it's imagination or a real thing the supposed benefit balanced brings to phone listening. And because I have the chance to do it.
About the internal wiring, I imagine just cutting the connector will allow me to see if they are separate.
I'm having some difficulty identifying which is the 2.5mm right plug for the balanced interface.
Slew is totally moot for headphones.
Doubling-up the amplifiers "can" double the peak output voltage, useful if you can't use a proper battery voltage.
I had a long post written to help you with incorrect statements. Most of them don't relate to your actual goal. So, if you must proceed, here is an idea or two.
Get a 2.5mm TRRS plug and your favorite wiring etc and build a cable. Diagram below. It is 100% up to you to verify FIIOs pinout, but it's likely to the standard below. I think A&K had an odd one that deviated from below at some point, so it's important.
What I personally might do is buy something like this...
https://www.amazon.com/LC-2-5B-LC-3...t=&hvlocphy=9010632&hvtargid=pla-531244160288
Then I'd whack off the IEM connection ends, shorten to the length I prefer, and connect the wires to my HPs. Dress wires / add strain relief accordingly.
Note - the link is the first example that popped up. I am sure there are cheaper options, and I would not buy from a source that lists that it's a USB connection.
The only guidelines I'd follow are: to ensure it's a 4-wire cable intended for balanced HPs or IEMs: that it follows the FIIO pinout; and to not buy Litz wire, but that's just me. I hate prepping Litz / coated wiring for solder. Some love it. YMMV.
I have no idea what model HPs you have and whether or whether this will be worth your time and effort. Taking apart HPs can be a challenge. Actually, taking them apart is not too hard. Getting some of them back together to original spec is a bit of a job. 😀
It's been mentioned before, but ensure you have L+, L-, R+, and R- wired accordingly to each transducer. If you don't, the results could be disappointing.
Either way, I hope you have fun, and that it's a rewarding experience.
Get a 2.5mm TRRS plug and your favorite wiring etc and build a cable. Diagram below. It is 100% up to you to verify FIIOs pinout, but it's likely to the standard below. I think A&K had an odd one that deviated from below at some point, so it's important.
What I personally might do is buy something like this...
https://www.amazon.com/LC-2-5B-LC-3...t=&hvlocphy=9010632&hvtargid=pla-531244160288
Then I'd whack off the IEM connection ends, shorten to the length I prefer, and connect the wires to my HPs. Dress wires / add strain relief accordingly.
Note - the link is the first example that popped up. I am sure there are cheaper options, and I would not buy from a source that lists that it's a USB connection.
The only guidelines I'd follow are: to ensure it's a 4-wire cable intended for balanced HPs or IEMs: that it follows the FIIO pinout; and to not buy Litz wire, but that's just me. I hate prepping Litz / coated wiring for solder. Some love it. YMMV.I have no idea what model HPs you have and whether or whether this will be worth your time and effort. Taking apart HPs can be a challenge. Actually, taking them apart is not too hard. Getting some of them back together to original spec is a bit of a job. 😀
It's been mentioned before, but ensure you have L+, L-, R+, and R- wired accordingly to each transducer. If you don't, the results could be disappointing.
Either way, I hope you have fun, and that it's a rewarding experience.
I had a look and didn't find your comments to my incorrect statements.
Anyway, the drawings and diagrams you included have been very helpful to show what the connections should be for the 2.5mm Fiio socket.
Also found a quite clear video on what connections you might find inside your headphone, that might help others to rewire for balanced interface. Mine are Sony MDR-7506, which I have few of, so I will be able to compare balanced and unbalanced phones. directly.
https://www.google.com/search?clien...y+MDR-7506#kpvalbx=_dtTWYabYOdLD5OUPn5iM6A435
Anyway, the drawings and diagrams you included have been very helpful to show what the connections should be for the 2.5mm Fiio socket.
Also found a quite clear video on what connections you might find inside your headphone, that might help others to rewire for balanced interface. Mine are Sony MDR-7506, which I have few of, so I will be able to compare balanced and unbalanced phones. directly.
https://www.google.com/search?clien...y+MDR-7506#kpvalbx=_dtTWYabYOdLD5OUPn5iM6A435
