Sennheiser HD25-1 Diagnose and Repair




This instructable will show you how I fixed the cable connection to Sennheiser HD25-1 headphones.

I bought these off a friend, they're 8 yrs old but instantly became my favorite cans.  They developed an issue where sound would cut or reduce volume in the left driver, this was temporarily fixed by jiggling the connector where it meets the driver until sound restored.  I decided to fix the connector once and for all.

I searched the net and found many others with the same problem, a common flaw in an otherwise flawless and indestructible pair of headphones.  
The common suggestion was to replace the cable (Min $50 for a Sennheiser 1.5m steel cable) or replace the driver (even more expensive and unnecessary for this issue).

My fix costs $0, works perfectly, and all you need is a soldering iron and some solder.

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Step 1: What You Need.

To open the capsule and get to the internal connectors (diagnose only) :
-Small flat head screwdriver

For the cable connector fix:
-Needlenose pliers
-Soldering Iron

Step 2: Diagnose

Easy to diagnose and repair these headphones since each component is user replaceable.

This is an extraneous step if you have the same loose connection issue, but I thought it may interest some people.  If not, go straight to the fix.

1. Remove the problem headphone (in this case the left one)
2. Remove the foam & vinyl covering
3. Use a small flat head screwdriver to pop off the capsule cover
4. Tweezers or needle nose pliers to remove the small white plastic that shields the connectors

The internal connectors are two small springs, if there is no rust or otherwise visible damage to the internal connectors then the problem lies in the cable itself.

Step 3: Fix Em!

Get that soldering Iron good and hot.  All we are doing is lightly tinning the tips of the connectors to make them slightly larger and creating a better connection.

Each cable connector is made of two pieces of steel that tend to split if damaged.  Use needle nose pliers to hold each connector together, this will also act as a heatsink so that you don't melt the plastic of the connector.

Get a small drop of solder on the end of your iron and apply it to the tip of each connector, sit the iron long enough that the connector takes it evenly

NOTE: Do this very carefully, if you add too much solder the connector ends may not fit.

Step 4: Enjoy

Carefully re connect the cable, observing the proper orientation (one connector is slightly larger than the other).  It may be a little stiff at first but gently work it in and it should work great!

I've tugged and moved mine listening to music and can't make it cut or degrade the signal where it would have easily cut out sound before.

Hope this works for you as well as it did for me!

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    14 Discussions


    4 years ago

    Well, i screwed up. Broken the capsule to cable wires while attempting to remove the small white protector. Can it be fixed? Or i just lost my headphone?

    1 reply

    Reply 2 years ago

    did you manage to fix this?/ Either mine was broken and that was the problem all along, or I did what you did.

    Thank you so much! its been 1.5 years of cutting out on my 25's fixed them in 10 min, you guys rock :)

    Thank you so much! its been 1.5 years of cutting out on my 25's fixed them in 10 min, you guys rock :)


    5 years ago on Introduction

    Thanks for your guide! I just fixed my left can using your guide (exactly the same issue you described) and while I melted the plastic a little bit, I was able to force them back together and it works WAY better now, than it did! Great how-to!


    5 years ago on Introduction

    If you re afraid to iron, this is what I did and it s working well so far:

    remove the small springs and twist inside some spare copper wire ( I used an old RCA broken cable)

    This will improve the connection and can be redone many times...


    5 years ago on Introduction

    Thanks a loot! you saved my capsule! i bought one pair of hd-25's 6 years ago and since then one capsule had a bad spring and sound was dropping when moving around. You made my day! Now works perfectly


    6 years ago on Step 2

    Great tutorial thank you for this. I had the exact same problem and tried with the soldering iron with no luck unfortunately. In the end I had to buy a new driver to get my Sennheiser headphones working again unfortunately, If others don't have any luck with the fix then I got the driver here. Sennheiser Headphones - HD25 SP Drive Unit


    7 years ago on Introduction

    Hey everyone, I've signed up just to let you know there is an even easier way to repair this fault with HD-25s.... No solder required.

    Follow the above instructions up to step two. Take a look at the springs that form the connection between the plug and the driver. Between the coils you'll see three gaps, let's call them 1, 2 and 3. (if you're wondering which end is '1' and which is '3', it really doesn't matter).

    You will see that the two pins on the plug sit within the gaps of the middle coils of the two springs, gap 2, making contact with the spring, and hence forming the connection.

    Now, the problem you have is that one of these gaps in the coils is a little too wide, so it's not gripping the pin very tight.

    What you need to do is unplug the pins, then carefully remove the offending spring using tweezers or needle nose pliers. Now, using tweezers or your finger nails you need to carefully squeeze gap 2 closed, work it for a bit until you think it has become narrower.

    To compensate for this you can do the opposite to gap 1 or 3 or both, so that the spring will still sit snugly when you replace it.

    So, when you're done, replace the spring, put the whole thing back together.

    No solder required. I did the entire job with my leatherman.


    7 years ago on Introduction

    Thatks for such a useful post! I don't need to repair my Sennheiser headphones now as they are working just perfectly, but if they fail I'll know what to do)


    8 years ago on Step 4

    Just finished soldering my headphones and they now work perfectly.

    Thanks a lot for the top advice


    8 years ago on Step 3

    Worked perfectly for me! im even purchasing another pair of sennheisers in order to fix and resell em!