[decemberflower]

Well, I just bought these headphones, and they sound way better than my HD6XX. However, I noticed there's a extremely obvious imbalance on the right side.

Lo and behold, I go to check the cables and this is what I see: https://streamable.com/xrwju

As you can see, the right side is not tight at all. Of course I can just get a replacement from Amazon since I literally got them a day ago, but my question is: is there any way to screw it in or something? I'm a majoring in software dev, but any hardware I touch seems to die, so hopefully nothing too difficult.

Shame that these headphones have amazing sound, but are very obviously built in China.

 

[GREQ]

This model (ok... technically the whole brand) has been plagued by quality control issues.
(there's no lack of negative reports on all the usual websites, and both the Hifiman headphones I've owned, HE-400 and HE-500 had various faults develop)

Opening it up would void the warranty, so it's not recommended at this early stage.
Also as far as I can tell, nobody else has done a near-full disassembly of this one yet that I've seen.

Looking at the exploded diagram of all the parts, I don't think it will be as easy to reach the socket as the earlier models, and even then it's most likely held in place with glue, rather than a threaded socket + nut as one might expect.
But that's beside the point. Channel imbalance could be other problems unrelated to the integrity of the socket mounting.
I would rank channel imbalance worse than 'driver failure' as what appears to be driver failure is often just a loose or cold solder joint.
Imbalance requires actually replacing one or both drivers, as they are no longer a matched set.

I would save yourself the stress and exchange it for a replacement or refund.

 

[decemberflower]

This model (ok... technically the whole brand) has been plagued by quality control issues.
(there's no lack of negative reports on all the usual websites, and both the Hifiman headphones I've owned, HE-400 and HE-500 had various faults develop)

Opening it up would void the warranty, so it's not recommended at this early stage.
Also as far as I can tell, nobody else has done a near-full disassembly of this one yet that I've seen.

Looking at the exploded diagram of all the parts, I don't think it will be as easy to reach the socket as the earlier models, and even then it's most likely held in place with glue, rather than a threaded socket + nut as one might expect.
But that's beside the point. Channel imbalance could be other problems unrelated to the integrity of the socket mounting.
I would rank channel imbalance worse than 'driver failure' as what appears to be driver failure is often just a loose or cold solder joint.
Imbalance requires actually replacing one or both drivers, as they are no longer a matched set.

I would save yourself the stress and exchange it for a replacement or refund.

Thank you for your reply In this case, I suppose I will exchange it for another one. That is quite unfortunate because I really did enjoy how they sounded, minus the channel imbalance. If I continue to receive defective models, I am not sure what I will do.

 

[StickySli]

I'm trying to revive this post since I found the issue for anyone wondering. This issue is not a driver imbalance per-se. In reality it is the jack's own contact resistance that is causing the problem. Try to wiggle the cable and you'll hear the imbalance appearing and disappearing. It might not disappear if your connector is jack crap, pun intended. In any case, I discovered this by using a multimeter and playing with the connector. The resistance of the right channel varied from 40 Ω up to 1 kΩ. After further non-destructive analysis, I found out that Hifiman is using a jack that is tin-plated and not gold-plated, and the jack is so badly designed that it barely makes contact with the ground terminal of the sleeve of the TRS plug.

I'll try in the following weeks to replace the crappy jack with a PJ-327A gold-plated SMD jack. The quality seems to be better and it also looks that it will fit the headphones.
I'll post pictures of the procedure when I get the new connectors.

 

[dunring]

I've had a few Hifiman apart, if it's the spring clip that puts pressure when you plug it in, it's not worth trying to fix if you can return or exchange them. When you register the warranty for any Hifiman product, if you follow them on Facebook with the same email address on your FB account, they extend it to 18 months. If you bought from Amazon, they have an Asurion warranty for $16 a month, which will instantly cover any Amazon electronic purchase going back two years.
https://www.amazon.com/Tech-Unlimited-Protect-Devices-Cancelled/dp/B07RZ3LSHM
This can be a lifesaver if it's speakers or something heavy, since they pay for shipping labels to send it in. Just one month of coverage is all you need, but they have a deductible for items over $500 (I think it''s $99). There's no repair available for Hifiman out of warranty, they just offer you 20 percent off a new purchase (selling it for parts on eBay is probably a better option than 20 percent off full retail).
The spring clip on most models is inside a little square plastic casing, which will melt if you try to solder around it. I always test things with a phone decibel meter and online test tone generator when I get headphones in.

 

[StickySli]

I've had a few Hifiman apart, if it's the spring clip that puts pressure when you plug it in, it's not worth trying to fix if you can return or exchange them

It truly depends on your will to do the repair yourself. It does not seem to be particularly hard from my point of view, but who am I to judge.
I've been a month without headphones due to having a problem with my previous headphones, Audio Technica ATH-R70X, and after 22 months of use Amazon asked me to just return them for free and I would get my money back. With the money, I bought some second hand Sundaras in good condition with earpads missing (I have plenty), and broken cable. The cable is indeed broken, but the connector is the worst part since it was not specified.
In my case, I'm willing to wait 10 days to receive the replacement connectors which are higher quality. I'll desolder the old PCB in case I need to send the headphones for warranty in the future, and I'll replace the PCB with the jack by a small piece of plastic with the jack glued to it. Then I'll solder the wires directly to the jack.
I have good soldering skills and a good soldering station. I am not worried about the jack melting since I will not be desoldering it, only the PCB will be removed. That just happens if you use a soldering iron instead of an SMD hot air station for this kind of repairs.

 

[StickySli]

Update on the Sundara jack replacement with the PJ-327A gold-plated SMD jack. ALMOST A DISASTER! not quite, just clickbait. Well, the jack was about 0.1mm too wide and almost did not fit in the CNC carved hole where it's supposed to sit, but with some elbow grease and some finicking, I managed to push it in with the back of my precision screwdriver. Steps below with images:
1. Disassemble the Sundaras. I will not go into detail since there are countless examples in YouTube on how to reach the insides. But what I will tell you is to use much care specially with the screws. Mine had a crossthreaded screws and apparently were all magnetic. If I had dropped one, I might have punctured the driver and the mesh too!
2. Once you have the driver outside the housing, carefully lift off the jack + PCB combo as it is not glued or pressfit at all (at least mine).
3. Cover the driver with something, but do cover it please! Also, use the screwdriver to hold the cables in place.

4. Desolder the jack. How you ask? The method I used is simple. Heat one pad and make some upward pressure. Move to the other pad, repeat. Move to the other pad, repeat... and eventually the jack comes off. After 3 or 4 cycles, the jack came loose. Here is the PCB for reference. Note how the "L" silkscreen label above the cable is connected to the pad to the left of it (or right depending on your perspective). The "G" pad is connected to the furthest pad (or not), I did not measure it and I don't plan on explaining the Pythagorean theorem to you.

5. The third step is to... wait this is the 5th step... I lost track since I am doing this mod very late after a long day of work. Anyways. Ignore this step.
6. The Pajama jack (PJ, get it?) will not match the two NPTH holes in the PCB. Easy fix, remove the frontmost peg with a pair of pliers or just using some sideways pressure since the plastic is very rigid. Image below shows the peg removed.

7. Since one peg is gone and also the pads on the PJ jack has a 20% matching ratio with the pads on the PCB, we will need to glue together the PCB with the jack, or vice versa. I used some old E6000 I had lying around which has a slow cure in air (no UV). I know, it's crap, but who cares.

8. Position the jack as straight as possible so it will have a higher chance of fitting the cup. Then solder one pad followed by the other. I used some Mundorf Supreme solder with some Chipquick no-clean SMD flux. The "L" cable will have to be soldered to the OPPOSITE SIDE of the connector, close to the "G" cable. This is because the PJ connector has a mechanical switch, and we are not interested in soldering the cable to the switch but the tip contact which happens to be on the opposite side. Do not be tempted to solder the cable on the exposed metal on the topside of the jack since the jack will not fit the cup.

9. Now, with care, jam the jack in the driver! Yes, you will need to apply some force but it will fit. Just make sure to insert the jack as straight as possible. I also found it easier if the jack is slid in and not inserted from the top. YMMV
Note: the mesh on the back does not seem to be metallic. I have tested it myself with a multimeter since I was worried I could short the pins.

10. (Optional) Test the continuity of the connector. You will have to touch the cable to the top left on one probe and with the other probe, insert it inside the jack since the other cable is inaccessible. You should get a reading around 32 ohms nominal.
11. Reassemble the Hifiman Sundaras. Take care with the screws. If they seem too hard to screw than they were to unscrew, you might be crossthreading them. Unscrew all the way out and try again. Screw in all the screws until you are satisifed, but if your Sundaras are like mine, I'd be too scared to put too much pressure.
12. FINAL RESULT: (pardon my oh-so-cheap Openheart cable, it looks exactly like that in person). The jack is stiffer than a grandma's walking stick, plus the sound quality is superb compared to the old tin-plated 0.01$ jacks Chifiman decided to use on a mid-fi headphone. The plug also does not have any leeway like before.

I hope this post cheered you up and has been useful to ya'll.