[shleepy]

I knowingly got a pair of K500's that have a small distortion problem on the left driver. I then got a working driver from another head-fi member. Today, I took the left side of my K500 apart, only to realize that the drivers are slightly different (same size and whatnot, but some very noticeable differences). So, I'm wondering if the "original" driver was even a K500 one, if it was from a different batch, or what... I'm a bit weary of trying to solder it in there.

So, in the middle of my "original" driver, there are 6 plastic lines radiating out from the center. As far as wires go, there's a white and a red wire on opposite sides of the driver.

In the driver that I received from a head-fi member, there are 12 plastic lines radiating out from the center. The wires are red and black and are next to each other.

If you have a K500, which do you have? You can judge by the number of little black plastic lines radiating out from the center of the driver, which you can see if you look in the very middle.

Should I bother trying to replace it, or would it sound completely different?

Would AKG have a pair of drivers that would fit in there (K40x/50x/60x/70x) available for cheap?

Thanks!

 

[shleepy]

bump

 

[ericj]

Try it. See if they sound different.

they came from different production runs but may sound close enough to exactly the same.

To answer the more general question: AKG has replacement parts for probably most of the k400/500/401/501 lineup. And the drivers will not be cheap. You'd have to call AKG to be sure, but i'm guessing that the total cost of buying two replacement drivers will be in excess of finding another used pair of K500's.

 

[QQQ]

Hi ericj.
Are any of following cans base on same driver: k401, k500, k501, k601? Or they're all different?

 

[ericj]

Quote:

Originally Posted by QQQ /img/forum/go_quote.gif Hi ericj. Are any of following cans base on same driver: k401, k500, k501, k601? Or they're all different?

The major difference between them is the driver.

Fitz even says that there are at least 3 versions of the k400 driver alone, but that they are all almost precisely the same. As you can see, assuming you got your replacement driver from someone who wasn't totally confused, there are at least two versions of the K500 driver.

AKG admits to there being two versions of the K400 and K500, but i forget if the drivers had different part numbers (for the early and late versions of K400 and K500 respectively).

There's a lot of information in the service documents - which are available to anyone who clicks on the microphone instead of the K701 at the AKG.com website. But AKG doesn't always admit everything -- there are at least 3 versions of the K501 but AKG insists that all K501's are the same.

 

[QQQ]

ericj, thanks.
I've browsed through the service docs and found interesting - looks like k601 and k701 have very similar driver- DKK45. But the last digits in part number are different, which lead me to assume that only slight tweaking is the difference between the two drivers... Crazy idea: maybe k601's drivers are connected in series with a pair of resistors which bumps the impedance close to 120ohm, while k701 rated as 62ohm. That also explains(aside from enclosru\pad differences of course) slightly warmer sound sig of k601 and more colored sound..? Please tell me what you think.

 

[shleepy]

QQQ, that last number does mean that they're different drivers. The one with the 6 matches the K601 and the 7 matches the K701. It's just up to how many different service documents they have for their series (e.g., the one available for the K500 is one that's for K400/401/500/501, while the K240 one is for all the K240 versions, starting with the sextett and going to the Mark II).

ericj - thanks for the info!

 

[QQQ]

Yes, but i guess these drivers are from same "family"?

 

[ericj]

Quote:

Originally Posted by QQQ /img/forum/go_quote.gif ericj, thanks. I've browsed through the service docs and found interesting - looks like k601 and k701 have very similar driver- DKK45. But the last digits in part number are different, which lead me to assume that only slight tweaking is the difference between the two drivers... Crazy idea: maybe k601's drivers are connected in series with a pair of resistors which bumps the impedance close to 120ohm, while k701 rated as 62ohm. That also explains(aside from enclosru\pad differences of course) slightly warmer sound sig of k601 and more colored sound..? Please tell me what you think.

It is extremely unlikely that the K601 driver has a series resistor bumping up the impedance. I would be utterly gobsmacked if that turned out to be the case. As far as i know, series resistors and passive eq networks are presently only done with balanced armature IEMs, because their coils are necessarily tiny and thus some of them very low impedance - like the 5-ohm IM716 armature.

More likely, the voice coil wire is thinner, and there are more turns of it on the coil.

Also, just because the K601 driver and K701 driver look similar does not mean that they are made of the same material.

DKK45 is just the terminology they use to describe that family of drivers. And yes, they are all in the same family, but they all sound different. All of them will fit in eachother's frames. There are also some K300 and K301 frames with DKK45-sized baffles.

I own just a K401 and a set of K500 drivers that are stuck in an extensively modified K300M frame. And i heard a K701 for about a minute two months ago.

I can tell you for sure that although the K401 and K500 drivers look pretty similar, they don't sound the same. There are subtle differences.

Fitz tells us that all K4xx and K5xx sound substantially similar. I basically trust him in that. There's also scompton's thread comparing K400, K500, and K501. I'm tempted to loan him my K401 so he can flesh out that corner of his review.

from what i hear, the K601 is a bit different, and the K701 is a major departure from anything AKG has done before.

I still think you should install your driver and see what it sounds like. You might not be able to tell the difference.

 

[QQQ]

Thanks, pretty insightful.
Also, regarding this:
Quote:

As far as i know, series resistors and passive eq networks are presently only done with balanced armature IEMs, because their coils are necessarily tiny and thus some of them very low impedance - like the 5-ohm IM716 armature.

There were pictures of old Beyer 880 or 990 with resistors at the driver soldering points...

 

[ericj]

Quote:

Originally Posted by QQQ /img/forum/go_quote.gif Thanks, pretty insightful. Also, regarding this: There were pictures of old Beyer 880 or 990 with resistors at the driver soldering points...

I have a 1980 beyer 880 and a 1985 beyer 990.

Those are zener diodes. They protect the voice coil from excess voltage. Unless they are way over driven, they never enter into the circuit.

I forgot that Sennheiser does some sort of passive eq in like the hd201 or something. Some low-end closed can.

Using a resistor to alter the impedance is really wasteful and you won't see it in a high-end design.

 

[Fitz]

Quote:

Originally Posted by QQQ /img/forum/go_quote.gif Hi ericj. Are any of following cans base on same driver: k401, k500, k501, k601? Or they're all different?

Quote:

Originally Posted by QQQ /img/forum/go_quote.gif Yes, but i guess these drivers are from same "family"?

They're all in the same "family" yes, but the drivers in each headphone are different enough that you don't really want to mismatch them if you don't have to, as the small differences may get irritating over time. I've never really compared K500 drivers though, so they may sound close enough to get away with despite being from different production eras.



Quote:

Originally Posted by QQQ /img/forum/go_quote.gif ericj, thanks. I've browsed through the service docs and found interesting - looks like k601 and k701 have very similar driver- DKK45. But the last digits in part number are different, which lead me to assume that only slight tweaking is the difference between the two drivers... Crazy idea: maybe k601's drivers are connected in series with a pair of resistors which bumps the impedance close to 120ohm, while k701 rated as 62ohm. That also explains(aside from enclosru\pad differences of course) slightly warmer sound sig of k601 and more colored sound..? Please tell me what you think.

The "DKK45" just means it's a 45mm dynamic headphone driver, that's all. I don't even need to look at a K601 to know that they aren't using a series resistor in such a manner... I may not be too fond of AKG's recent products, they do know better than that.



Quote:

Originally Posted by ericj /img/forum/go_quote.gif I can tell you for sure that although the K401 and K500 drivers look pretty similar, they don't sound the same. There are subtle differences. Fitz tells us that all K4xx and K5xx sound substantially similar. I basically trust him in that. There's also scompton's thread comparing K400, K500, and K501. I'm tempted to loan him my K401 so he can flesh out that corner of his review.

The K401 is probably the most different out of the four, if only because it handles the treble in a somewhat different way than the rest of the family. But if you just slapped any pair on my head and started playing a random song, I doubt I'd be able to easily tell right away which model I was listening to, because of the subtlety of the differences. The numerous production variances certainly don't help to make the models stand apart from each other either, but that's just the way AKG is.

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Using a resistor to alter the impedance is really wasteful and you won't see it in a high-end design.

I think the only time I've seen any kind of passive components added to a (non-cheap) headphone at the factory (besides protection zeners) is on the K1000, which I haven't actually examined in detail. I suspect it may be some kind of eq to compensate for all the cancellation caused by the backwave, but I'm not sure.

 

[QQQ]

Thanks for explanations!