There are so far 3 versions of the K501 which have been presented on Head-Fi. The following versions are what I think is the order they came out as (oldest to most recent). Also these photos are not mine and do not remember who’s post I took these off of, but if these pictures are yours please contact me and I will give you credit for them.
Now on to the different versions:
First up is Version 1, this is the one I presume came out in the fall of 1996. Going from the inside of the driver out, there are 3 long openings out of a possible 6, and on the next level 4 smaller openings out of a possible 12. With a black dampening covering them.
Courtesy of Asr
This is Version 2, which is quite a significant difference. I have no idea when this one came out. There are 6 long openings and 12 smaller ones with a white dampening material which is thick.
Courtesy of Fitz
And lastly Version 3, which only has 6 long openings with no smaller ones with a white dampening material as well, but is thinner and more porous than the Version 2 one.
Courtesy of Mrvile
Now you might be wondering why I said 6 long/12 small opening combination was the maximum. If you look at adanac061’s Ver. 1 you can clearly see that AKG thought of making/testing different versions from the beginning, so my hypothesis is that the 501 was an experiment.
Courtesy of adanac061
Also another hypothesis is that considering that all the different versions have the same driver and that the black/white difference in sound is negligible that Ver. 2 can sound like both Ver. 1 and 3 just by blocking up the different holes.
If you would like to check what version your 501 is, just twist the pad counterclockwise to reveal the driver and openings.
I currently have Ver. 2 from rhester which I just received and am going to give them a good listen to when I get back home.
Special thanks to Fitz, adanac061, Mrvile, Asr, and the whole K501 community
EDIT: Under further investigation the order of the versions should be 2>1>3, I will keep the version numbers as they are to solve any confusions and change it when we have significant proof of the order of the versions
EDIT 2: added the differences between the V2 and V3 dampening material
Now on to the different versions:
First up is Version 1, this is the one I presume came out in the fall of 1996. Going from the inside of the driver out, there are 3 long openings out of a possible 6, and on the next level 4 smaller openings out of a possible 12. With a black dampening covering them.
Courtesy of Asr
This is Version 2, which is quite a significant difference. I have no idea when this one came out. There are 6 long openings and 12 smaller ones with a white dampening material which is thick.
Courtesy of Fitz
And lastly Version 3, which only has 6 long openings with no smaller ones with a white dampening material as well, but is thinner and more porous than the Version 2 one.
Courtesy of Mrvile
Now you might be wondering why I said 6 long/12 small opening combination was the maximum. If you look at adanac061’s Ver. 1 you can clearly see that AKG thought of making/testing different versions from the beginning, so my hypothesis is that the 501 was an experiment.
Courtesy of adanac061
Also another hypothesis is that considering that all the different versions have the same driver and that the black/white difference in sound is negligible that Ver. 2 can sound like both Ver. 1 and 3 just by blocking up the different holes.
If you would like to check what version your 501 is, just twist the pad counterclockwise to reveal the driver and openings.
I currently have Ver. 2 from rhester which I just received and am going to give them a good listen to when I get back home.
Special thanks to Fitz, adanac061, Mrvile, Asr, and the whole K501 community
EDIT: Under further investigation the order of the versions should be 2>1>3, I will keep the version numbers as they are to solve any confusions and change it when we have significant proof of the order of the versions
EDIT 2: added the differences between the V2 and V3 dampening material
