Since ive got all the different pads (i think) I took it upon myself to take a few hopefully good pictures. I also included some photos of the different cables that comes with the "Plus" package and also an aftermarket cable from Oyaide.
Unfortunately I have sold my Yaxi pads so I cant make a picture comparison but i will explain why I dont recommend them. They are very comfortable, and of a very good quality but when it comes to the sound they ruin it a bit with taking the edge off in both highs and lows. They take away that special HD25 "magic sauce". The reason why, you can see below in picture #2. The Original Sennheiser pads has a plastic funnel that leads to the center hole in the pad. You can see in the $2 AliExpress pad that its just fake leather on both sides. This makes the sound dull and as I said before removes much of that special raw edge that the HD25 has. This is especially true for the comfort pads from Yaxi since they use a fussy like suede leather that absorbs even more sound than plain leather.
I will say that all the Sennheiser pads has the same or very like foam inside. The sponge/springy-ness all depends on the cover. The backside of the pads with the plastic funnel has a ventilation hole in it so that the pad can compress and decompress.
The original vinyl pads gives very good isolation, as good as the Amperior pads. They sound very good and seems to hold up very well over time. I think these are cheap, very functional pads that are meant to be changed after they go through hell and back. They are sweaty, but they sound the best when they get a little sweaty and the ultimate seal against the ear takes place. Ear sauna all year long since the fabric does not breath at all.
The Velour pads gives least isolation and also takes away some from the sound but its very little but this depends on how picky you are. They are also very similar to the old HD555/595 pads in the texture/fabric.
The Amperior pads texture/fabric is like HD598CS pads. They are my favourit pads all around since they dont make my ears sweat and at the same time give high sound isolation and are very comfortable.
The Aluminium pads gives the best isolation and comfort in regards to softness but they are a ear sauna during the summers. I cant say if this is real leather or not, my guess is not but i cant say for sure. VERY good fake leather if so.
The $2 AliExpress pads are stiff, deformed
itchy and crazy sweaty.
Regarding cables i recommend the Oyaide cable. It's cheap, sleek and durable. The 3,5mm connector is very slim and made in one durable piece. I think i got mine from Amazon for €18 or something like that.
http://www.oyaide.com/ENGLISH/AUDIO/products_category/headphone_earphone_cbl/hpc-hd25.html
The standard straight cable is longer than you would probably like on the go and in the winter time it gets very stiff. The 3,5mm connector is also very large. This cable can take some rough beatings and it wont fail. Its built like a tank like the rest of the HD25.
The spiral cable i have not used but i guess it's as durable as the standard straight.
The Custom Cans Mass Loading & Damping Kit for HD25 was not for me. It made the bass softer and deeper. It also took away some of that agressive highs that i like in my HD25.
https://customcans.co.uk/s/s/index....loading-uber-mods-mods-uber-damping-kits.html
The product code/number for Amperior pads are: 549336
The product code/number for Aluminium pads are: 556906
All the Sennheiser spare parts can be order through you local retailer with no extra cost added. The Sennheiser Sweden customer support told me this and i have had no problems ordering parts through my local retailer.
Overview
Standard pad that comes with HD25-1 II (Also included in Plus package)
Velour pad that comes with HD25-1 II Plus
Amperior pad that comes with HD25 Amperior
Aluminium pad that comes with HD25 Aluminium
$2 from AliExpress
A thin net was sown in to the back but that had to go since i use the standard foam inserts.
Standard straight cable
Oyaide cable
Comparison Standard straight VS Oyaide
Custom Cans Mass Loading & Damping Kit for HD25
Bonus picture of my cat Bajjen (the turd) borrowing my custom HD25 with Amperior pads and 2,5mm balanced silver cable.