Because my stock pads are getting ripped out, and Sony does not want to sell me some, also, I don't feel like ordering a few in Japan because the shipping and handling costs more than the pads even if I bought three pairs, and lastly the sound of the CD900ST with the stock pads is getting bad because it is already thin due to wear and tear maybe? I bought fake pads from ebay instead. Well actually I bought two different kinds of pads for the CD900ST-- the other one is using protein leather or faux leather I think? Similar texture to that of Sony XB700/1000 pads.
I'll give quick impressions about the sound while changing the pads, do not take my word for it completely though since I only listened to them for a few minutes, before switching to the pad that I am going to use.
But first, I'll give the sound of the CD900ST with its current, worn-out pads. Due to wear I'm guessing, the pads become thin, making the drivers closer to my ear. So that awesome midrange is nowhere to be found majority of the time. When I listen to poorly recorded tracks, vocals become shouty and I have to turn down the volume for me to able to listn to those kinds of songs properly.
Lets go to the first set of replacement pads. This is probably the usual pads that we get from ebay for $1 to $3. I bought these set of pads for a low low price (sarcasm) of $6 simply because it was neatly packaged in a box, preventing it to be compressed in any way at all during transport. I recall measuring the stock pads and it is around 15mm thick, while these fake pads also measured 15mm thick according to the seller where I bought the pads when I inquired about it before buying.
For those who bought those kinds of pads before also probably know how it sounds, midrange is muffled and overall clarity/detail is lessend because of the dust cover being really thick, and it even has an unremovable padding that is made up of foam. I may need to cut those covers and attempt to stitch the stock CD900ST dust cover in those pads, or I'll just tape the stock pads on the earside baffle instead.
On the plus side, I kind of like how it sounds despite losing its clarity and midrange. Since the pads are thicker and also the cover is thicker, the "shoutiness" is definitely gone and it gives abit of headstage since the pads are thick. I'll post a pic later on how thin the stock pads are due to wear.
The second set of pads that I bought, is using different material altogether. Even the dust cover is different! The material used for the dust cover for these pads is really close to the stock pads, which is awesome. They also provided a separate foam instead of stitching it at the back like the first pads i bought.
As for the sound, its obvious that it is not muffled since the dust cover is also thin, so it retains in detail and clarity, while also giving abit of better headstage since the drivers are farther from the ear compared to stock.
Lastly, both replacement pads' foam are somewhat stiff, I guess that is normal compared to the stock pads because these are new, and the stock pads is probably at least 3 years old. Stiff does not mean that it is uncomfortable though! It is still as good as the stock pads in terms of comfort.
I will "test drive" the leather pads after work, to see if it is indeed as comfortable as stock pads.
I'll also provide more pics from my potatocam when I'm at home, can't use my potatocam here in the office.