[bukujutsu]

I want one because I've read that you can remove hissing with them. Turn the volume down on the cable until there's no more hissing, then turn the volume up on the source (e.g. computer).
 
Radio Shack is selling them for about $10 which seems like a complete ripoff.
 
http://www.ebay.com/sch/i.html?_odkw=Volume+Control+Cable+-flex&_stpos=94703&_fcid=1&gbr=1&_localstpos=94703&_osacat=0&_from=R40&_npmv=3&_clu=2&_trksid=p2045573.m570.l1313&_nkw=Volume+Control+Cable+-flex+-board&_sacat=0
 
This one is the cheapest: http://www.ebay.com/itm/New-3-5mm-M-F-1M-Stereo-Headphone-Audio-Extension-Cord-Cable-with-Volume-Control-/270831486718?pt=Other_MP3_Player_Accessories&hash=item3f0ed086fe#ht_3582wt_1270
 
This one looks nicer, but I can't see how the volume control works: http://www.ebay.com/itm/3-5mm-Stereo-Headphone-Audio-Extension-Cord-Cable-with-Volume-Control-For-iphone-/150831987892?pt=Other_MP3_Player_Accessories&hash=item231e497cb4#ht_2829wt_1037
 
What do you think?

 

[scootermafia]

Looks like an OK deal, but a better idea would be to use a USB DAC with your computer.  Lots of inexpensive ones like the Hifiman Express HM101 replace whatever underperforming sound card is causing your hiss, you just plug it in with USB to any computer then plug your headphones or amp into the DAC.

 

[tzjin]

That would best. if you are looking for something simpler and cheaper, look for 75-ohm adapters on eBay. Etymotics makes some for their ER-4P to make it into an ER-4S, but theirs is expensive. You can get them in 25 to 150-ohm types.

 

[bukujutsu]

Update: It works. 
 
 
 http://www.ebay.com/itm/New-3-5mm-M-F-1M-Stereo-Headphone-Audio-Extension-Cord-Cable-with-Volume-Control-/270831486718?pt=Other_MP3_Player_Accessories&hash=item3f0ed086fe#ht_3582wt_1270