Modding the Sennheiser HD428S

I just picked up a pair of refurbished Sennheiser HD428S headphones. I think they sound pretty good for the price... with the exception of the ridiculously thin cable and occasional microphonics... it's a good purchase for a headphone. I want to disassemble these completely and re-wire everything out to a removable cable (and even add a microphone attachment for future gaming purposes. My only problem, I can't get these darn things apart... even after pulling the ear pads. If anyone has information on how to do this... it would be greatly appreciated.

I'll be darned... I didn't see ANY scews, but there was felt sticker once the ear cushions were removed... so I started peeling away the felt... and there were screws... THANKS!

Would the damping material kill some of the bass? It can almost get nauseating with the amount of bass these headphones make (depending on song).

Well, they're done... and it wasn't the easiest thing I've tried. I tried to keep it single entry, but that wasn't happening with 24AWG wiring (I used Mogami 2534 since I had it lying around). So, I had to go dual entry.

I ended up stripping the wiring from the Mogami cable and then braiding.

Yes, it wasn't a HUGE difference, but they seem to clean up a bit in all directions as well as the bass isn't as sloppy as it was when I first got them. All in all, I say it was worthwhile to do the re-cable. I attempted to do it as a single entry, but the wiring used wouldn't fit through the headband without A LOT of finessing. So, dual entry was in order.

It most likely was the music I was listening to, but I was listening to some David Guetta stuff, and the bass was definitely there and hard hitting... but seemed overly done and didn't keep up. I've listened to the same tracks on my Turtle Beach HPX (which has close to the same amount of bass) but seemed to keep pace with the song better. My AKG K240s (that I sold) after a Canare cable upgrade seemed to keep pace with the bass the best out of my phones, but didn't have much impact.

Unfortunately, I didn't listen to some of my Metal tunes with this headphone prior to the re-cable, as I would have liked to see if there was a difference on some tracks where Metallica (or similar) use the double bass drums and double tap each one for a really quick bass that sometimes gets muddled together (as they did on my father-in-laws Bose QC2 headphones).

Though, in the end... I like these headphones, and for the price...they're very difficult to beat. They even sound fairly nice for Jazz too. These are my new Rock/Metal headphones (as they don't require a GREAT headphone to represent that genre). I will keep searching for my perfect closed headphone, and I think a Woodied Denon would possibly be it, but I can't find a place to audition in my area.

I actually paid $20 for these off of Amazon as Refurbished models. I think I just may grab another pair before they're all gone. I had purchased them from BestBuy originally for $74, but returned them (unopened) when I saw on Amazon the refurbished one. Sounds good for a $74 phone (even if the cable is pathetic), sounds really nice for a $55 phone.... Sound incredible for a $20 phone.

If it makes ANY difference, I was listening to FLACs off the PC through a uDac.

I just realized that I only posted the before and after pics of the re-cable for the HD428S... I think it's time I posted all the pictures of the build up...

Well, I opened the package and looked at that dinky cable and said "What, what were they thinking!?" I put them on my head... played a few tracks of differing styles of music and 'lo and behold', they weren't bad at all.


Still couldn't get over the cable tho. So, I decided to rip them apart and give them a proper cable. I chose Mogami W2534 (I did buy 50ft of this stuff) as my cable. I first pulled off the pads and looked for the screws retaining the drivers to the cups themselves (thanks for the info apatN).


After pulling the drivers out, I looked behind... these things are in a sealed enclosure... cool I thought, till I realized that since they were buried in their.. I have to use an Exacto blade to cut the glue and slowly pry apart their custom enclosures to get to the drivers themselves.



After getting them apart, I removed the soldered wires and drilled out the opening to allow the Mogami to pass through. Got everything wired and glued down all the openings with Hot Glue (including the newly drilled opening for the larger wire). I trimmed off the strain relief from the previous cable and drilled an opening barely large enough to fit the Mogami cable (now sheathed in 1/8" nylon) into both cups. Here are the finished products. You can read above on the sonic changes that were affected. These are nice headphones, I just realize the Supra-Aural thing is not for me. My ears are too sensitive I guess.

Well, the Modded HD428 were well received by the NEW Owner! I'm happy he likes them!

For the music you listen to... I think you'd like one of my new headphones... a Modded Grado SR80i.  Very nice, tight bass (not Gobs of it though), excellent highs and Mids (the Highs are slightly rolled off using a felt mod).  Overall... my fav headphone at the moment.  Saving up for a pair of AKG K701/702.