[Eraldo Coil]

I am about to purchase the Sennheiser HD25-1 II and I wanted to know what AMP I should get to complement it. It need to be relatively cheap and be able to power them nicely. I am kind of new to High end headphones so any recommendations and tips are welcome.

 

[Mad Max]

They are so easy to drive, anything will do, lol.  If you go too cheap, you will bottleneck your HD25's sound.  Since they are as sensitive as IEMs, they can hiss a lot if the amp does not have a low enough noise floor.  Avoid FiiOs for these reasons.  I'm not sure about the E11, however.
I imagine that the UHA-4 (not so cheap) should rock, or possibly one of the iBasso slim amps.

 

[Puffery]

Try the JDS Labs cmoy I love it with my HD25, when you order it you can get the impedance matched as well.

 

[musicisthekey]

I find that HD25 are very easy to drive. The sound fantastic with any mp3 player. I have not tried them with a portable amp though.

 

[Cassadian]

C421.  The new amp has a lower gain.

 

[SirStarfish]

I've found that my Senn HD25's sound better unamped compared to amped with my Fiio E7....
 
Personal preference.
 
Although i should say i'm looking forward to trying out the new Fiio E17 

 

[proton007]

I'd say try them out first without an amp. But you haven't mentioned what do you use them with.
Considering the SPL of 120 db/mW, they do not seem that hard to drive.

 

[fabio-fi]

My E7 does justice to them (despite is mainly a Dac) you can also look at other alternatives such as the E11