[Knarfje]

Hej,
 
For some time, I've heard some rattling sound coming from the left channel of my beloved AKG K-400. I first checked if there was maybe some hair or other stuff causing this, but unfortunately that was not the case. Opened up the left can and by accident loosened one of the cables attached to the driver. I guess the connection was already bad, as it loosened quite easily. Also got of the other cable of the driver and tested the driver on its own, the rattling still occurred. So it's the driver itself.
 
According to the service manual the driver/capsule is part number 2400Z0001. Online I can only find one source the has this part (http://www.cimplespares.com/product.php/17583/0) but they do not ship to the Netherlands. Somebody knows where to get this part? I will also mail to service@akg.com but I do not expect that they supply these parts directly to customers?
 
Furthermore, according to the service manual you only have to replace the capsule that is defective. So I don't have to worry about a mismatch with the old driver (after the new driver has been burned in some time of course)? I mean, it would be quite possible that the new drivers that are being produced now are not exactly the same as they were made about 15 years ago? Would it also be possible to replace both drivers with the drivers of the 'higher' models, like the K-500/K-601/K-701? Or don't they fit physically? Or maybe they would not sound right in the K-400 housing? I ask, because when looking at the price of the drivers of those models (at Cimple Spares) they are all about the same price ... so maybe upgrading is worthwhile?
 
Ok, assume I have the replacement driver(s), then I want to try fixing it myself. I do not have any experience with soldering yet, but I wanna try/learn. Do you think it should be doable for me then? Maybe the trickiest part is that before you can start soldering the cable to the pins of the driver, you have to install the driver and three plastic parts that come on top of it into the complete can, which makes the pins not so easily accessible, not an easy start for a soldering beginner )
 
By the way, are gas soldering irons any good for this kind of jobs? Most are multifunctional, in which case you can use it for heatshrinks too. Would be handy to have it in one tool (when going to do some more (re)cabling stuff). Or is it better to stick to electric irons for this kind of work?
 
Thanks in advance,
Frank

 

[MCC]

Please do email AKG's support. When my Sennheiser HD-595 developed a rattle I emailed them and they were able to ship me a brand new driver for ~$20 USD. I don't see why AKG would be any different. After I installed it I did a special burn-in routine of pink noise, silence, sine sweeps and some music on just the new driver. The two channels sounded different at first but they're matched now that the new driver has had time to settle in. This is despite the fact that the older driver probably has 2000+ hours lead on the new one- I used those headphones A LOT before I got my AD2000s.
 
As far as the newer drivers being different, that I don't know. Perhaps you could ask AKG?
 
For the soldering, make sure you have practice first. I started by assembling some kits for flashing lights, noise generators, etc. that are easily attainable online. You want to minimize the soldering time to the driver as much as possible so I would recommend adding a tiny bit of flux to the driver contacts and the wires before you solder them. 
 
I only have experience with electric irons- a cheap pencil iron should do the job but my new Hakko 936 is MUCH quicker and makes cleaner joints. I wouldn't invest in one unless you plan on doing a lot of soldering though.

 

[Knarfje]

Thanks for your reply and helpful tips MCC. I did mail AKG two days ago, haven't got a response yet, but hey it's summer holiday )

 

[Knarfje]

Hmm, got a response:
 

Hello Mr. Borghans,

Sorry to say that we do not have the K 400 drivers anymore.
If you are interested in new headphones I would say take a closer look to the K 601
- it's a wonderful sounding headphone which offers a detailed sound.

Kind regards

 
A little disappointing. I'm going to mail back, as I asked in my initial mail, if they have some contact in The Netherlands of a company that has AKG replacement parts. Maybe there are still some in stock or so. Especially because the Cimple Spares appears to still have the replacement part ...

 

[ujamerstand]

Maybe try the company here?
 
http://www.head-fi.org/forum/thread/490588/akg-k1000-and-k340-driver-replacements

 

[MCC]

I hope you can find a new driver! It would be a shame to retire such a fine pair of headphones because of a replaceable part. When it comes to electronics I prefer to repair rather than replace- it's (usually) fun, saves money, and is less wasteful.
 
Example: Dad owns a business with about 10 computers and the power supply units fail every so often. I already have two repaired units sitting on the shelf ready to replace the next failed unit (usually Antec) after which I'll add the capacitors or whatever is needed to fix the dead unit to my next part order. Saves about $40 each time and the repaired ones haven't had issues yet.

 

[Knarfje]

Thanks, ujamerstand, rw-soundsystem.de indeed has some K400 drivers! They go for about €30 a piece. Yay \o/