2025-05-17 - Flaky Material on GXT 414 Zamak Headphones
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I've had some GXT 414 Zamak headphones lying around for years that were
rescued from a giveaway/throwaway pile. The problem was that the foam
had completely disintegrated, or rather not really the foam itself,
but the thin material on top of it. This meant that they were very
annoying to wear because little pieces of black material would get
everywhere. After procrastinating for a long time, I finally decided
to look at them more closely. Unfortunately, I don't have any "before"
images because I originally wasn't planning on writing an article
about them, so the images are mainly from the reassembly.

The foam cushions covering the earpieces were in pretty bad condition,
so I took those off. You can buy new ones still, but I first wanted to
see if I could still get the old ones into a usable condition. It turns
out that scrubbing them with soapy water worked fairly well. There
was regular cloth underneath the black flaky material on the outside,
so I could just scrub away the flaky material[0]. I guess another
option would have been to cover the entire cushion with a different
piece of cloth, but that wasn't necessary in this case. Putting the
cushions back on can be a bit difficult because the bottom parts
have to be stretched very tightly to fit over the earpieces. I used
a pointy tool to help push them into the crack that holds them on[1].

The other issue was the flaky foam on the part that goes over the
head[2] (in this picture, I had already peeled off some of the flaky
material from the top, and the earpieces had already been detached).
In this case, I decided to try covering it with a piece of cloth.
Luckily, I have a piece of stretchy material lying around that I've
been cutting pieces out of for years now[3]. I cut out a rectangular
piece with the correct dimensions, then sewed it together along the
long side and turned it inside out so the seam wouldn't be as visible.
Since the material I used was a bit stretchy, I made the width a bit
smaller than necessary so it would stretch nicely over the old foam.
I also made the piece slightly longer than necessary so I could hide
the ends inside the plastic pieces that are used to screw the earpieces
to the part going over the head.

Putting the cloth on is a bit more involved since at least one earpiece
needs to be disconnected first. There are screws on the sides that
can be used to disconnect the earpieces[4][5] (yes, I know that the
cloth piece has already been put on in that picture). I removed these
on both sides since I wanted to hide the ends of the cloth piece. On
one side, the earpiece itself also has to be disassembled in order to
desolder the cable connecting the two sides. There are four screws on
the earpiece that have to be unscrewed before the upper part containing
the speaker can be separated from the rest[6]. I opened the earpiece
containing the audio jack, so there was a circuit board inside[7], but
I'm assuming that the wires are connected directly to the speaker on
the other side. The wires were additionally covered in glue which had
to be removed before they could be desoldered, and there was a knot
before the hole going to the outside that had to be untied. The wires
can then be pulled through the hole in the side to completely detach
the earpiece from the rest of the headphones, after which the piece
of cloth can be pulled over the wires and the part that goes over the
head. Once that is done, the wires can be pulled back through the hole,
the knot can be tied, and they can be soldered back in. Ideally, the
glue should also be replaced[8] (I used neutral-cure silicone glue).

Finally, the plastic parts on the side can be screwed back
together[9][10]. This can be a bit fiddly, especially since the ends
of the cloth piece are also stuck between the two plastic pieces. The
end result turned out pretty nice, though[11]. I guess it would have
been possible to just cover it in cloth from the outside without taking
apart the earpiece, but I wanted to make it a bit more "professional".

Completely by chance, I came across some replacement foam cushions
that someone didn't need anymore, so I ended up replacing those after
all[12]. I won't throw away the original ones, though, since they're
still fine and could be used if the new ones break or I need them for
other headphones.

All in all, this was a fun little repair combining sewing and
soldering. I'll probably give these headphones away since I already
have another pair that's perfectly fine for my purposes[13]. The only
part that's missing is a microphone which can optionally be plugged
into the side, but that isn't necessary to use the headphones.


[0] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/foam_cleaned.jpg
[1] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/foam_reassembly.jpg
[2] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/flaky_foam.jpg
[3] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/cloth.jpg
[4] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/side_screws.jpg
[5] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/side_disassembled.jpg
[6] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/screws.jpg
[7] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/wire_glue.jpg
[8] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/wire_glue_replaced.jpg
[9] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/side_reassembly.jpg
[10] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/side_reassembled.jpg
[11] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/cloth_attached.jpg
[12] gopher://lumidify.org/I/phlog/2025-05-17-gxt-headphones/final.jpg
[13] gopher://lumidify.org/0/phlog/2025-05-17-sennheiser-headphones.txt