# [GUIDE] Balanced AKG K702 with detachable 4-pin mini-XLR cable



## castigar

This is my first audio DIY, as well as my first guide here on Head-Fi. 
	

	
	
		
		

		
			





 I posted a while ago about how feasible this project would be, and since then, I've went out and bought all the stuff I needed to try this out. And the results: IT WORKS!






*[size=small]Introduction and Idea[/size]*
 Balanced operation requires 4 channels going into your headphones (L+, L-, R+, R-). The stock AKG K702 has a 3-pin mini-XLR connector for detachable cables, and there exists many cables from people like ALO that replace the stock detachable cable that fit into this slot. However, the 3-pin forces only 3 wires (channels) going in to the headphones.

 Thus, I got the idea to replace the stock 3-pin with a 4-pin connector. That way, I can actually get 4 channels into the headphones, and it keeps the detachable design that I like about the K702. I also built the cable from 4-pin mini-XLR to 4-pin XLR as well, which was relatively simple.


*[size=small]Warnings and Notes[/size]*
 As a warning, this mod involves opening up the side of the headphones and pressing out the stock 3-pin mini-XLR jack, which is not a delicate matter. Specifically the part where you have to press out the stock jack. If you plan on doing this mod, you should be ready to order spare parts from AKG. I sure did.

 Also, excuse me for not posting pics of the entire process, I got too excited when I got all the materials, and never stopped to take photos as I went along. I'll try to be comprehensive in my descriptions of what I did to make up for it.


*[size=small]Materials and Tools[/size]*
 All materials used for this project was bought from Redco Audio, who offers some great prices for a lot of DIY projects.

 Cable: 6ft of Mogami W2893 Miniature Quad Mic Cable
 Heat Shrink: 6" of 1/4" Heat Shrink
 Connectors:
 Redco male 4-pin mini-XLR
 Redco female 4-pin mini-XLR
 Neutrik NC4MX-B (4-pin male XLR)
 Neutrik NC4FX-B (4-pin female XLR)
 Neutrik NP3C-B (1/4" TRS plug)

 I had my own set of tools, but here's what you need for this mod:
 soldering iron, solder, wire stripper and cutter (or a sharp knife!), multimeter (for continuity check), superglue, press (or is there some other way?)


*[size=small]Part 1: Opening Up the Left Side[/size]*
 This is the first scary part. To get access to the wires, start by removing the left grille. Take a thumbtack, twist it counter-clockwise, and pull out. Be careful, you don't need to turn much for it to come out! And it also doesn't pull out very easily, so don't expect it to come falling off when you've turned it.

 Once you open that, you should see something like this:




 Next, remove the two screws on the ear cup. Now to remove the ear cup and get access to the wires, you must pinch the sides of the ear cup and pull outwards. This part is quite hard, and you must use quite some force to get it out! You also have to unsnap the headband guides from the ear cup. This is probably the first scary part. Once you get that you'll get to something like this:



 (this image is actually after the mods, the wiring's already done in this one)


*[size=small]Part 2: Desolder Internal Wires[/size]*
 I don't have a proper picture for this, as the below picture was taken after I did the mod. But the stock AKG K702 has the common ground (L-, R-) soldered together. To get balanced configuration, we need to separate the two channels. If I remember correctly, the two ground wires are both white. The next picture shows which lead is which channel:




 Also desolder the wires from the ear cup's stock 3-pin mini-XLR connector.


*[size=small]Part 3: Press Out the Stock 3-pin Connector[/size]*
 Sorry I don't really have pictures for this. But the idea is to get the tiny little connector out (the small piece of plastic with the 3 pins through it). My roommate got the idea to use a press and a small metal rod to force it out of the ear cup. So we went to the machine shop and did so. We pressed the rod into the connector out through the cable slot in the ear cup. This was probably the scariest part of the entire project, but it worked out in the end. Though we got the ear cup a bit scratched up...

 If there's any other way to remove it without brute force, please let me know!


*[size=small]Part 4: Place in and Connect 4-pin Connector[/size]*
 First, take apart the male 4-pin mini-XLR connector, and there should be a small plastic piece with the 4 pins through it. This will replace the 3-pin one we removed.

 First, solder the inner leads (the shorter ones) to the wires on the headphones. Refer to the above picture for which lead is which on the headphone. As for the pinouts for 4-pin XLR:
 pin 1 - L+
 pin 2 - L-
 pin 3 - R+
 pin 4 - R-

 You should now have the 4-pin connector dangling from the side of the headphones. Now place the connector into the ear cup from the inside. This part is a bit delicate, so be careful. Once it's snugly in (for me, it didn't fully go in all the way like the previous 3-pin connector did), apply 2 or 3 drops of superglue to the sides of the connector on the inside of the ear cup. 

 The superglue makes sure that the connector doesn't wiggle when you connect a cable to it. I initially didn't apply the superglue, as I thought the connector was snug enough that it wouldn't wiggle, but when I tested it, it did. So do apply some superglue!








 At this point, we're done with modifications to the actual phones. So, snap the earcup back into place (also kinda scary). Then replace the two screws, and replace the left grille we removed.


*[size=small]Part 5: Build Cables[/size]*
 This part has probably been documented all over the place, so I won't go into excruciating detail. I took the 6ft of Mogami W2893 I got and cut it down to make an additional adapter to 1/4" TRS for single-ended operation.

 For the main cable, we just want 4-pin female mini-XLR to 4-pin male XLR (the large one). Pretty simple to make, but there's a slight annoyance here. The mini-XLR connector doesn't fit the Mogami cable entirely (with all the insulation on). I could only fit the 4 internal wires through the hole, so I had to use some heat shrink to insulate this and provide a bit of strain relief. This is also why I stripped more from the mini-XLR side.

 1. Slide on the strain reliefs and clamps from both connectors first! Don't be like me and forget to do so for one connection, and then have to desolder the plug to get them back on!
 2. Slide on the 1/8" heat shrink onto the cable as well, we'll need this when we're done to insulate the 4 wires at the mini-XLR end.
 3. Remove all the insulation from both ends. Get about 3/4" from the regular XLR side, and about 6/4" from the mini-XLR side. For the Mogami, this means the outer rubber, the thin shielding wires, the paper-like wrapping, and the cloth-like threads. We want just the 4 internal leads. Strip a tiny amount from these leads, maybe about 1/8" or so.
 4. Assign a lead color to a pin number. I used Red - pin 1, Blue - pin 2, White - pin 3, Black - pin 4.
 5. Solder leads from both ends to the connectors according to your color assignment from the previous step.
 6. Use a multimeter to test for connectivity from one end to the other. Make sure no wires from different channels are touching internally.
 7. Screw on the outer plug onto both ends.
 8. Position the heat shrink over the bare 4 wires at the mini-XLR end. Use a heat gun (or in my case, a hairdryer) to heat it up, and it'll shrink and fit snugly around the wires to provide strain relief and insulation.

 End Result:




 I also made a balanced female 4-pin XLR to male 1/4" TRS adapter so I can still use my current SE amp. This one's more or less the same as the previous cable, just much shorter, and you must connect pin 2 and pin 4 (L- and R-) to the ground lead on the TRS connector. The TRS connector's leads are connected like this:
 ground (L- and R-) goes to the shielding ring
 L+ goes to the middle lead
 R+ goes to the top lead

 When connected to the other cable I made:





*[size=small]Final Thoughts[/size]*
 In the end, the mod turned out pretty well, I think. I can't really comment on how the cable I built compares to the stock cable, as I can't really ABX it: the stock one doesn't fit onto the new 4-pin connector. I'm not really a cable believer (don't flame me, please <__<), but I am intrigued by balanced operation.

 Now all that's left for me to do is save up money for a balanced amp like the LD MKVII+ and a balanced DAC too... sorry, wallet.

 I hope this helps for anything thinking about balancing their pair of these wonderful headphones! Please offer some critique and/or comments! Wondering how I did for my first DIY mod...


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## getllamasfast

Did you notice a huge difference in sound after you balanced them?


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## castigar

So I don't have a balanced amp to actually use them in balanced operation yet, if that's what you were wondering. If you're wondering if balancing them and using a balanced amp makes a huge difference in sound, I always like to refer to this thread:

http://www.head-fi.org/forums/f5/lit...lanced-463006/
 and this post:
http://www.head-fi.org/forums/6475106-post140.html

 If you're wondering whether the recable made a difference in SE operation, I can't really say. I don't really remember the sound of the stock cable, as I pressed out the 3-pin connector a few days before the materials for the recable arrived, so I didn't get to listen to them for a while. When I tried them after the recable, I had forgotten what they used to sound like. I guess I could try making a 4-pin mini-XLR to 3-pin mini-XLR adaptor to be able to use the stock cable again for ABX'ing, but that means getting more supplies.


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## m1abrams

Nice write up.

 Suggestion for you since you went to all the trouble to keep the disconnect feature of the headphone why not instead of using an adapter for the TRS just make 2 cables for the headphone. 1 TRS and 1 XLR. This would make the cable much less bulky and reduce the number of contacts you have in the chain.


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## castigar

I was considering that, but decided that if I wanted a dedicated single-ended only cable (TRS), I might as well make a 4-pin mini-XLR to 3-pin mini-XLR adapter, and then plug in the stock cable into that. It seems more modular that way, so I could potentially even use other people's cable upgrades for the K702.

 I do agree with you that the cable is bulky as hell though. Hopefully, I'll get that balanced setup sometime soon, so I can get rid of the adapters and go to audio nirvana. That and make my wallet cry in the corner.


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## elwappo99

I was googling mini 4 pin xlr, just to see what parts were available to think about doing this mod, and I found this thread!  Glad to hear it's possible, and I'll definitely give it a try sometime! Great Mod, and I can't believe there isn't more talk about this!


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## sokolov91

Quote: 





elwappo99 said:


> I was googling mini 4 pin xlr, just to see what parts were available to think about doing this mod, and I found this thread!  Glad to hear it's possible, and I'll definitely give it a try sometime! Great Mod, and I can't believe there isn't more talk about this!


 


  yeah really! lots of people including myself would have purchased the 701 just to retarminate if they wanted a cheap balanced K70X.. this almost as easy and no funds are lots switching up headphones!
   
  Good to see someone has their thinking cap on!


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## ulyses

I just finished my k702 balanced mod. Thanks castigar. I never get brave enough for this operation if your guide does not exist. I melded existing mini xlr with soldering iron and it's easily leave it's place without harm around it. So there is no need to use brutal force if you don't care waste existing xlr jack.


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## castigar

Quote: 





ulyses said:


> I just finished my k702 balanced mod. Thanks castigar. I never get brave enough for this operation if your guide does not exist. I melded existing mini xlr with soldering iron and it's easily leave it's place without harm around it. So there is no need to use brutal force if you don't care waste existing xlr jack.


 


  You used your soldering iron to dislodge the mini-XLR? Well I hope you were wearing a mask and not breathing in the fumes from burning plastic! But whatever works, right? I'll admit It's a lot more convenient than having to find a press. Good to hear that this guide I wrote almost a year ago is useful!


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## ulyses

Yes it works. There weren't too much smoke actually. The part have different type of plastic than headphone's case. It's getting like coal after melded. And the only job is cleaning it with thin metal rod after that.


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## Joefish

I found the guide to dismantling the phones very usefull, thank you.
   
  I would add that you should shield at least one channel in the cable as the amount of crosstalk between the wires in this cables would be significant, the CMR would negate the crosstalk, however, it would be best if it were not there in the first place.


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## liamstrain

These cables (the mogami 4 conductor) have individually shielded conductors, and manage pretty well without significant crosstalk for all manner of studio applications.


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## RexAeterna

going balanced alone eliminates crosstalk cause the negatives act as a ground cable as well. that's why older studio headphones always used a 4-conductor balanced wiring with either a 1/4'' balanced TRS jack or a Balanced DIN connector(DIN connector for european models).


anyways,congrats on the successful mod. i wish more headphones started making use of 4-pin XLR connectors. they're so versatile when you need it to be. have you tried making a 4-pin XLR to bare wire for speaker outputs? that can become very handy when your craving more power or need it.


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## castigar

I have not tried it, but I can't imagine it'd be too hard. And I definitely agree that 4-pin XLR should be used more, though I can see the large size of the connector being a disadvantage compared to other balanced connectors (like the one used on the RSA Protector). Though the larger connector does also mean it's easier to solder...


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## RexAeterna

naw,not difficult at all to make a 4-pin XLR to bare wire cable. great using speaker outputs cause power is no concern and damping factor as well cause speaker output impedances are always close to 0 ohms if your worried about impedance matching if it's solid state. if you use tubes your gonna have to use a resistor at the speaker outputs cause tubes highly rely on their power transformer(s) for output impedance matching and it's the power transformer that gives the tubes it's output impedance. Solid state is doesn't matter if you stock 1000ohm headphones or 32ohms. it will match the impedance no problem if it's a good push-pull design.


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## liamstrain

Quote: 





castigar said:


> I have not tried it, but I can't imagine it'd be too hard. And I definitely agree that 4-pin XLR should be used more, though I can see the large size of the connector being a disadvantage compared to other balanced connectors (like the one used on the RSA Protector). Though the larger connector does also mean it's easier to solder...


 


  Agreed. I'm surprised the 4 pin mini-xlr is not more popular for this usage. But the full size is bunches easier to work with.


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## RexAeterna

it's cause the full size 4-pin xlrs are design for speakers and pro equipment use and can accept much thicker gauges of wiring. they can accept up to 10-12 gauge wiring depending on the how the connector was design and using them for speakers the connectors actually don't seem very big at all using the thicker gauges. headphones it's super easy cause most headphones use only up to 22 gauge the thickest so soldering them to such a big connector is walk in the park. i only know pro audio uses XLR as a standard. i have no idea why it didn't reach it's way to the ''audiophile'' market. all they have is that ridiculous dual 3-pin XLR cable for balance use you see everywhere which i find completely unnecessary since 4-pin is already balanced as well and will add way less bulk and great if you want to keep the headphone single entry.


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## Hooster

Quote: 





rexaeterna said:


> i only know pro audio uses XLR as a standard. i have no idea why it didn't reach it's way to the ''audiophile'' market. all they have is that *ridiculous dual 3-pin XLR* cable for balance use you see everywhere which i find completely unnecessary since 4-pin is already balanced as well and will add way less bulk and great if you want to keep the headphone single entry.


 
   
  Amen. I could not agree more. The dual 3 pin is absurd.


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## DutchGFX

Where can I find a cable for 4 Pin mini XLR to 1/4"? I can't find one! Thanks for the help


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## nikongod

Quote: 





dutchgfx said:


> Where can I find a cable for 4 Pin mini XLR to 1/4"? I can't find one! Thanks for the help


 
   
  You could make one.


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## DutchGFX

I have been looking into that, I ordered the connectors. I really just need a part list, like cable, solder type, whatever else I need, I a, an experienced solder master lol, so if you could just link me some parts it'd be greatly appreciated


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## alwayshungry

Here are the parts (Redco)
  1) 4 pin male mini plug http://www.redco.com/shopexd.asp?id=1296&bc=no
  2) 4 pin female mini xlr plug http://www.redco.com/shopexd.asp?id=1301&bc=no
  Remember the hardest part is getting the 3 pin male xlr out of the K702 housing. Good luck!


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## DutchGFX

What type of Solder? I have Radioshack rosen-core 60/40. Is that substancial?


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## liamstrain

Quote: 





dutchgfx said:


> What type of Solder? I have Radioshack rosen-core 60/40. Is that substancial?


 
  That will be fine.


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## DutchGFX

So tell me if this is the right procedure:
   
  I bought my TRS and my 4 Pin XLR, and my heat shrink tube, and my cable. The cable has 4 connectors.
   
  The cable SHOULD have 4 different color conductors, hopefully. So I will unscrew the body of the TRS and of the XLR, to reveal the solder points. I will look at the pin #'s and pinouts for the both connectors. I will put the cable through the bodies of both parts. I will then solder the correct colored wire to each corresponding part on the connectors. Then, I screw in the body pieces to their connector heads. I then cut the heat shrink tubing to appropriate sizes, and place it partially over the connector, and partially over the wire. I then use a blow dryer to heat and shrink the tubing. Done.
   
  Is that correct?


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## KimLaroux

Just try it. If it doesn't work, you'll learn something from experience, which cannot be replaced by reading How-To's.
   
  Just a tip: cut the heat shrink to lengths and slide it over the cable before soldering. It may not fit over the plugs.
   
  And most importantly: Use a DMM to check that the cable is conducting properly before connecting it. It's an easy way to ensure not shorting the output of your amplifier.


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## DutchGFX

I'm sorry but what is a DMM, I assume a multimeter, and how can I use it the check if my cable ismcorrect


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## liamstrain

Quote: 





dutchgfx said:


> I'm sorry but what is a DMM, I assume a multimeter, and how can I use it the check if my cable ismcorrect


 
   
  Yes, multimeter - check pin to pin (pin 1 on one end, to pin 1 on the other) for current, then check the other pins around (pin 1 on amp end vs. pins 2,3,4 on headphone end) it to make sure you do NOT get current. Repeat until you are convinced there are not possible shorts.


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## DutchGFX

So can I just get a multimeter at like a local radioshack? I do not really want to go out of the house this afternoon. Are the 2 blue/2 clear wires labeled by chanceo n the Mogami cable, so I do not need a multimeter?


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## liamstrain

Radioshack is fine - you only need a very basic model. 
   
  No the wires in 2534 are not labeled ... but beyond that, It's not so much the wires, but you want to make sure you didn't accidentally get any solder bridges causing shorts.


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## DutchGFX

Ahhhh, I understand. So I need to test every connection while shooting power threw 1 conductor to ensure the others are separate


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## KimLaroux

Yes there are many ways you can accidently short pins while making a cable.
   
  The easy way to test it is to plug the cable into the headphone, and then test the continuity between the "pins" on the TRS connector. It should look something like this:
   





   
  Between TIP and RING ~120 Ohms
   
  Between TIP and SLEEVE ~60 Ohms
   
  Between RING and SLEEVE ~60 Ohms
   
  If one of those shows 0 Ohms, you have a short. If one of those is infinity, you have an open circuit.
   
  Have fun.


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## szwety

Seeing as you replaced the cable for balanced use, does it not matter that the ricght driver will have a longer cable due to the fact that it's a onesided output?  If you were to rewire the phones with a better quality cable either cardas or silver or something, then would it be necessary to also rewire from the input jack to the left and the right cups?  I hope that makes sense lol, I'm planning on buying a pair of the q701's which have a similar setup and would like to experiment with some different cable setups for it!
   
  Thanks!


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## KimLaroux

Well, if you believe dual entry is inherently better, then you'll probably hear a difference. Otherwise, no, it's not a problem. 
   
  The main advantages of balanced cabling are still there, even if one side goes trough the headband. It would, in theory, raise the impedance of the cable for this driver. In practice, I bet the difference would be smaller than the variance in impedance due to soldering. In other words, you may find the same variance even in a dual entry cable, simply because the solder joints are not perfect and introduce resistance which may be different from one to the next.


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## szwety

Just to make sure that I understand what you're saying: So even if I wanted to upgrade to a silver cable, on a single entry style headphone, rewiring from entry point to the other driver wouldn't be necessary?  Wouldn't that change the sound from source to far cup due to the different cables?  I am quite naive when it comes to recabling, so I just want to make sure that I do it right


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## DutchGFX

szwety said:


> Just to make sure that I understand what you're saying: So even if I wanted to upgrade to a silver cable, on a single entry style headphone, rewiring from entry point to the other driver wouldn't be necessary?  Wouldn't that change the sound from source to far cup due to the different cables?  I am quite naive when it comes to recabling, so I just want to make sure that I do it right




In theory the advantage of dual entry is that you avoid the wire through the headband that MIT be low quality. In truth, that wire is small, and is pretty good quality on most headphones, that it doesn't really matter. 

I have a balanced Q701, single entry, sounds great. Balancing a headphone simply is separating the grounds, so you can have inverse signals.


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## KimLaroux

Though with AKG headphone, it is interesting. The two metal rods making the headband are used to carry signal from one cup to the other. These rods are probably made of a metal alloy chosen for its physical properties, not electrical ones. Then there are small wires soldered to the ends of the rods. So in practice, the right driver's signal has to go trough 4 additional solder joints and long metal rods. It may be interesting to measure the total impedance of this system. It may be significant.


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## DutchGFX

Quote: 





kimlaroux said:


> Though with AKG headphone, it is interesting. The two metal rods making the headband are used to carry signal from one cup to the other. These rods are probably made of a metal alloy chosen for its physical properties, not electrical ones. Then there are small wires soldered to the ends of the rods. So in practice, the right driver's signal has to go trough 4 additional solder joints and long metal rods. It may be interesting to measure the total impedance of this system. It may be significant.


 

 I thought there is a wire straight from the left driver to the right driver, no intermediate wire/pole. I could be wrong though


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## KimLaroux

Skip to 2:41 and then 4:20.


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## DutchGFX

Quote: 





kimlaroux said:


> Skip to 2:41 and then 4:20.


 

 I stand corrected! Thanks! I didn't know that. Cool vid, too .


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## DutchGFX

It looks silver in that pic, atleast its not OFC


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## joebobbilly

yea don't think the metal rods could be that much of a problem or there would already be significant left/right imbalance in the sound right? AKG probably considered that?? 
	

	
	
		
		

		
		
	


	



  
  just got my k702 annies... considering a possible future with balanced


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## AlanHell

I am not sure it is fully balanced when you only have one cable coming out of one side~~~
  I think a Y split will be a better idea here cause different length and material of the wire will lead to different resistance. If you care that much to turn the AKG into a balance setup, the last thing you will want is the channel imbalance caused by different wire resistance.
   
  P.S.
  The cable looks very nice!


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## joebobbilly

Quote: 





alanhell said:


> I am not sure it is fully balanced when you only have one cable coming out of one side~~~
> I think a Y split will be a better idea here cause different length and material of the wire will lead to different resistance. If you care that much to turn the AKG into a balance setup, the last thing you will want is the channel imbalance caused by different wire resistance.
> 
> P.S.
> The cable looks very nice!


 
   
  But how would you get it to Y split?, you'd have to drill a hole on the right side no? or would you order another left piece enclosure and hope it fits on the right side? can you even order that part? if so... where???? =)
   
  P.S. if going with a Y split would you have to somehow disconnect the connecting rods? wouldn't it possibly cause short circuit? Sorry if these are stupid questions... i'm a noob... not an electrical engineer


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## castigar

I think the cups are interchangeable, so you could probably put the left cup with the 3-pin mini-XLR onto the right side and do a y-split.
   
  As for where to order the cups, I think I just went to their website and found a number to call. There's no online store for parts AFAIK. There's also the service manual with the part numbers somewhere but I forget where I found that. This was all a couple years ago...


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## KimLaroux

I read, some time ago, that people who converted their K701 into dual-entry bought a Right cup to replace the Left one. Then they drilled a hole in the center of each cup.
   
  You can't really buy a Left cup to replace the Right one because the stock cable entry isn't centered. This would place the Right cable entry at the back while the Left one is at the front. Ugly.
   
  But anyways. As I said earlier, converting an AKG phone to dual-entry is overkill. You still get all the advantages of balanced operations even with a single entry. It's a nice project, though.


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## castigar

Ah that's true, it would indeed point to the back once you put the left cup on the right. Definitely agreed that dual-entry is overkill.


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## robrob

The term "balanced audio" really refers to two effects that both benefit sound quality. Most of us think of differential signaling--running an  in-phase and out-of-phase signal for each stereo channel--when we think of balanced operation. But you can get common mode noise rejection without differential signaling as long as the two + and - wires are of equal length, gauge and their impedance matche. *Note "equal length" refers to the individual wires in a channel pair so the extra length of the right channel wires will not cause an "imbalance."*
  
 I'm hoping to do this balance mod to my AKG K240 Studios.


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## zabzaf

I'm about to complete this mod myself. When I go to press out the existing jack, I'm a little unclear which direction to press the jack out. Down through the end where the female is inserted or up back into the headphone?


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## robrob

It comes out from the wire side. These are my K240s after I pressed the old 3-pin plug out:
  

  
  
 My detailed how-to is here: http://robrobinette.com/HeadphoneMods.htm#K240 Balanced Mod


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## zabzaf

Thanks! I'm going to tackle this tomorrow. Can't wait to get these going on my Mjolnir!


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## zabzaf

Ok, so I finally finished this mod.

Outstanding instructions and assistance was provided through this thread. Since this was my first mod, and first time soldering for that matter, here's my take on the whole thing...

First, make sure you put all the necessary sleeves and heat shrink on your cable before soldering it. I always wondered how this happened but I found out the hard way....

Second, mini XLRs are a pain in the ***** to work with. They are called mini for a reason!

Third, after beating on the old 3 pin XLR found in the headphones, I looked for alternatives around the house. I used a $1.99 spring-loaded center punch and it came out in one shot.

I am very proud of my work and thank this thread for giving me the confidence to take this on. 

Oh, and did I mention that the mini XLRs are a pain in the ***** to work with?


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## elwappo99

zabzaf said:


> Ok, so I finally finished this mod.
> 
> Outstanding instructions and assistance was provided through this thread. Since this was my first mod, and first time soldering for that matter, here's my take on the whole thing...
> 
> ...


 
  
  
  





  
 Congrats on a successful mod! Any comments on the K702 w/ Mjolnir? I've been hunting for a balanced amp for a year now, and I've always been tempted by that beast, but worried about that treble.


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## zabzaf

There's a lot of treble, no doubt. I'll have to reserve judgement at this time. I am a believer in burn in and I think these cans need some time, they probably had about 1 hour on them before the mod. I'm burning them in as we speak. I'll report back.

My other set of cans are HE-500s and they sound awesome on Mjolnir.


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## kugino

so i'm working on this  mod for my k7xx. i'm concurrently recabling a pair of practically new grado sr60 that i picked up for $20 on craigslist because one channel was not working.
  
 anyway, for those who know how to open the grado cups to access the drivers, it's usually done by applying heat to the cups using a hairdryer. this softens the glue and then the cups can be twisted and pulled apart. i opened my grados and thought this might work for the k7xx...so after opening the grill an getting to the actual connector part, i used the hairdryer for a couple minutes to heat up the connector. sure enough, i pressed on the inner part a bit with a screwdriver and it started to slide out. after the piece was out about a quarter inch, i grabbed that part with some pliers and was able to twist the rest of it out with very minimal force. as you can see in the picture, the wire end has some glue residue that holds the piece in...that's what needed to be heated so that it could be extricated with minimal force. hope this helps anyone who's attempting this mod. 
  
 just have to get my cable all wound and sheathed and hopefully will have everything done later this weekend...


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## Rob80b

kugino said:


> so i'm working on this  mod for my k7xx.........................................................
> i used the hairdryer for a couple minutes to heat up the connector. sure enough, i pressed on the inner part a bit with a screwdriver and it started to slide out. ..........................................................


 
 Hey kujino
  
 Thanks for the tip, planning on doing my K712s, thought that might work but just wasn't totally sure, although it may be easier to pop the 3 pin xlr while the holder is still in the socket?
 Debating if I'll even use a mini xlr or just hard-wire everything, always my preference when possible.


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## kugino

rob80b said:


> Hey kujino
> 
> Thanks for the tip, planning on doing my K712s, thought that might work but just wasn't totally sure.
> Debating if I'll even use a mini xlr or just hard-wire everything, always my preference when possible.


 

 cool. let us know how it goes. yeah, after i did it i wondered why i didn't just hardwire it...but i guess it's nice to have the option of switching cables, though these cables aren't readily available - you'll have to make them. i suppose if/when i sell these people might prefer a detachable cable anyway.
  
 oh, one other thing i had to do with the mini xlr (and which might sway you to hardwire it)...i had to cut off part of it to make it shorter, so i hacksawed a part of it off so that it would fit inside the cup.


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## Rob80b

My previous K701s cable already had 4 leads so it was a no brainer configuring for balanced.....and hard-wired at that.


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## kugino

rob80b said:


> My previous K701s cable already had 4 leads so it was a no brainer configuring for balanced.....and hard-wired at that.


 

 cool. i didn't know the k701 had four wires in the cable. i modded a k501 to dual entry and balanced and the cable had only three wires (like the k7xx) so it had to be recabled, desoldered inside the cup, etc...aah, i miss my k501. those were some good headphones.


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## Rob80b

kugino said:


> ............................... i modded a k501 to dual entry and balanced and the cable had only three wires (like the k7xx) so it had to be recabled, desoldered inside the cup, etc...aah, i miss my k501. those were some good headphones.


 
 Re-cabled mine also "way back when"......but  only singe ended...balanced amps were rare, but give em enough power.......


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## tumtuter

Is it possible to reupload pics for this guide? Thanks


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## jfunk

I Just made a short video of the operation which may help


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## gus6464

jfunk said:


> I Just made a short video of the operation which may help




Thanks for the video. What metal mini xlr connector did you use inside the headphone? Any brand will fit?


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## jfunk (Mar 9, 2021)

gus6464 said:


> Thanks for the video. What metal mini xlr connector did you use inside the headphone? Any brand will fit?



The rean ones fit perfectly
http://www.rean-connectors.com/en/products/tiny-xlr-chassis-connectors/rt3mp


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## canthearyou

Nice write up! Gonna perform this on my K7XX.


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## MattKT

I have an AKG k702 that I'd love to upgrade to a balanced connection, but I don't have the tools to perform this mod using the guide. Is there anywhere I might go to get this done rather cheaply if I provide the parts?


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## kugino

put a wanted in the FS section asking for a modder to help you out with this. i don't know what it's like now, but back in the day there were a bunch of ppl here who helped mod headphones for a very reasonable fee - many did it for the love of it. i've never worked with the k702 but have modded my k501 and the k7xx to be balanced, but i never put the mini XLR on there.


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