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Driver transplant from AKG K167 into Audio Technica SJ33

post #1 of 17
Thread Starter 

Well before I moved last month, I broke the hinge on the AKG K167 Tiesto.  The headphones were too new to get a replacement, so I decided to look for a donor body to harvest.  After many hours of trying headphones on I decided on the Audio Technica SJ33 body.


The requirements I wanted were:

- 40mm driver

- somewhat tight headband for isolation

- compact design that doesn't have a large gap above the ears

- decent quality earpad material

- appear durable with thick plastic hinge *ahem*

- foldable in some form

- low price


Thankfully, I'm in Japan where Audio Technica is slightly cheaper because it is Japanese.  The SJ33 was only $29.37 US.  The earpads on these don't leak until around volume 40 on the Fiio E7, which is loud enough.  They also isolate fairly well and I let a few friends try them already and they said it was "like being in your own world".  They are on the ear compared to the K167, but I can deal with that since the material is not hard.  The headband has no pads, but it doesn't hurt or anything.  I will try and find a foam sticker or glue a piece of fabric under it.


Some pics of the process in order, although I didn't take a pic of every step.  Stupid lens can't focus real close, so it's kinda blurry.





K167 on the left, SJ33 on the right.


The glue on the SJ33 was really gooey almost like rubber cement, so it was real easy to take apart with a blade.  I simply cut around in a circle a few times and the driver eventually started to come upward everytime I pulled the blade out.


The K167 drivers however were very hard to take out.  They used a stronger glue.  I had to cut some of the frame in every corner to make the plastic flex so that I could pop out a corner just enough for me to pull it out.


Wires connected.


The K167 has a rubber damper or something, whatever it was, I just left it on.


I tested it out before I screwed it back together to see if it worked.  Success.  I didn't notice I accidently burnt a corner with the solding iron haha.


The soundstage has become more compact as expected because the SJ33 is a much smaller earcup.  I might make a few holes on the SJ33 plastic panel inside to try and see if I can widen the soundstage just slightly.  If not, just cover the holes with tape.


The next step is to replace the cable and jack.  I'll have to look around to see if I can find a fairly cheap but decent quality cable.  I will have a longer cable too.


The great thing about the new body is that it doesn't have the large silver rings which attracted too much attention.  No one would even look twice at black on black headphones - that is until I put a nicer more durable cable on it, which I'm not sure if it will be black or not.

Edited by PFULMTL - 12/18/12 at 11:06am
post #2 of 17
Great job!!!!
post #3 of 17

This is interesting because I have a similar project going where I am taking the audio technica 900x drivers and putting them in some ATH-500s to make some cheap audiophile headphones. 

post #4 of 17
Thread Starter 


Originally Posted by Tjj226 Angel View Post

This is interesting because I have a similar project going where I am taking the audio technica 900x drivers and putting them in some ATH-500s to make some cheap audiophile headphones. 

Do you really need to keep the wing headband design?  Some cheaper and similar options are like the ATH-T400 for about $50.


I was trying to find a headphone with the same diameter earcup to use the K167 pads because I really liked them, but I kinda gave up.  It seemed like the larger the earcup, the less compact headphones get, aside from the K167, which was really compact for a fullsize headphone.  You might have better luck with yours because those look similar in size.  I really didn't want to spend more than $40 on something I was going to rip out its guts.

Edited by PFULMTL - 12/18/12 at 9:36am
post #5 of 17
Ow dioes the sound differ?
post #6 of 17

why not have it warrantied for a replacement? just wondering

post #7 of 17
Thread Starter 
Originally Posted by Dyaems View Post

why not have it warrantied for a replacement? just wondering

Because when I contacted AKG (US), they didn't even know the product existed.  They kept sending me to different departments.  So in the end, they couldn't help me.  I never bother with warranties anyway.



Prakhar - Yeah the soundstage is compressed and it sounds like it went back to a closed headphone.  I will be making some small circle holes in the plastic surrounding the driver to mimic the K167 design later.

Edited by PFULMTL - 12/18/12 at 8:42pm
post #8 of 17

Very nicely done!  I love transplant jobs.  I've been looking to do the same, but need to find a "donor" pair with about 1" of depth to handle the driver assembly of my Sennheiser HD-428 headphones.  The driver assembly is oval, and encased in plastic on the back of the driver.   The bass, after my mod is stellar and would retain much of the same bass (I'm sure) by going into a transplant.  Plus, the highs are detailed, but a bit less than the K167s that I had.  HD-424 (refurbed) for $40.00 + Donor pair - $0.00 (Unknown price) = quite possibly a very good set of cans.   To me, the modified HD-428 driver assembly, has a better enjoyment factor than my Sennheiser  HD-580 phones that I've owned in the past.

post #9 of 17
Thread Starter 

Alright, I got around to making some holes today in the grill and the soundstage is back to normal, which it was decently wide for a closed headphone.  I've been going back and forth testing it out with all the holes covered with tape and it surely sounds better with the holes uncovered because the original grill on the K167 had eight large circles surrounding the driver.  I might make another hole on the top and bottom later.  On some headphones, making holes will cause it to lose bass quantity for whatever reason.  Not entirely sure if this is the case here.  I need to compare it to an original one, but I can't find it here.


I think there is some amazing detail with these drivers.  I don't remember exactly how much bass these had before since I haven't heard them in about a month.  I know they weren't bass cannons.  I think it's about right, although I know the earpad material causes it to lose some bass.  Decent punch on some songs, but not boomy.  Still sounds great with all genres I have like rock, metal, and electronic.





I may look around for a new earpad that offers even better isolation if it's kinda cheap.  I also want to thicken the shell of the earcups to try and add more isolation by covering the inside with a layer of...something.

Edited by PFULMTL - 12/19/12 at 8:29am
post #10 of 17
Thread Starter 

Added a hole on the top and bottom.  May add another on the left and right to even it out. I couldn't center it in the middle because the inside of the grill has a perpendicular wall.

I tested it out without the earpads, and I realized that the SJ33 earpads do not compress as much as the K167 pads because there is more bass when the driver is right up against my ear like the K167.  I plan to make my own earpads that are the same diameter as the earcup and it will look like the earpads on the Aiaiai TMA-1 Studio, but with foam.  It will be able to fit my ear in it without touching the pad or inner grille almost exactly.  I've already brainstormed, now I just need to find that kind of foam here in Japan.

700 (left earcup)

Edited by PFULMTL - 12/20/12 at 2:34am
post #11 of 17
Thread Starter 

I got two 40mm Tiestos under the hood son.  Haha, I'm going to glue them on later.  The Japanese people here will do a double take.



post #12 of 17
Seriously awesome and I like that design way better.
post #13 of 17

Great job on the mod! 

post #14 of 17
Thread Starter 

After much thinking, I decided to just sleeve the stock cables for easier portability.  These will just be my portables as I do fold these up and put them in my jacket when not using them.  I saw some decent silver cables that were thin, but part of me didn't want to spend money haha.

I also made a cheap $1 headband from a piece of felt.  Wrapped it around once and I sewed it on by hand.  Feels nice now.



Next I will probably glue some felt inside the inner cup wall to maybe act as a diffuser to make it leak less.

Edited by PFULMTL - 1/1/13 at 8:49am
post #15 of 17

Nicely done! I was pretty interested in this since i owned a pair of SJ33 myself. Really good for portable use and keeps your ears warm in the winter :). If they had the AKG driver i don't think i would have parted with them :)).


Anyway great job and best of luck in your future transplants doctor!

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