[bukujutsu]

They're rated as having 24 ohm impedance. Is that too low? Devices they hiss with: Samsung Vibrant (Galaxy S), stock laptop realtek headhpone jack, Asus Xonar U3 USB sound card. They don't hiss with my Sansa Fuze, though. Why is this? 
 
Should I buy an impedance adapter? According to this: http://www.head-fi.org/t/601669/impedance-adapters-cables-explained-listed
 
 
 
 

Generally referred to when referring to an impedance adapter, but often used incorrectly, myself included. It essentially increases the output impedance of the source or amp.
Used to allow you to use more sensitive IEMs with your desktop amps. It lowers volume and raises the noise floor, essentially making your IEM's less sensitive.

 
http://www.ebay.com/itm/Etymotic-ER4P-to-ER4S-3-5MM-plug-resistor-adaptor-/270986675386?pt=US_Headphones&hash=item3f181084ba#ht_1852wt_1139
 
This is available in 50, 75, 100, 120, 240, and 300ohm impedances. Which should I get? Or is there another brand you'd recommend? 

 

[AstroTurf]

It may help.

I would prolly opt for the 75 ohm unit.

Give it a shot, Jim

 

[bukujutsu]

Why the 75?

 

[AstroTurf]

Well you are currently at 24.

And I think that anything over a hundred will require an amp.

Just my best guess, Jim

 

[bukujutsu]

Anyone else?