headphone amps

[JDC]

I'm buying a new sound card soon, and I'm looking at this new Asus Xonar Essence STX one with a built in headphone amp as one day I'll want to upgrade my headphones too but one thing bugs me

I've read rubbish on the internet that when you use headphone amps with mp3s, you can hear all the popping and clicking from the compression in the mp3s, but I've no personal experience of this

right now I use an audigy 2 and sennheiser pc150s for listening

so will using a headphone amp with say £200+ sennheisers murder my mp3 collection or not?

and how bad is this popping and clicking thing I've read about?

[Denim n Leather]

Grado RA-1 is a great choice.

[indysmith]

Popping and clicking should only be heard if there's clipping in the original recording, whether MP3 or not. (however some questionable internet-acquired MP3s seem to contain strange additional noises here and there).
A headphone amp will be a good investment for £200+ sennheisers, and there is a number of good ones popping up on the market at the moment.

In fact I'm thinking of selling my Graham Slee Voyager
http://www.gspaudio.co.uk/headphoneamps/voyagerheadphoneamplifier.htm
It's portable, 9V battery powered (lasts forever - 60hours+), or wall-wart powered, sounds beautiful, hand made in the UK...
Let me know if you're interested at all.

[Andrew W]

I have one of the original Musical Fidelity X-Can headphone amps that I bough off eBay for about £100 into which I plug Sennheiser HD-600 headphones.  These sound fabulous with a decent CD player but I do hear some of the chatter and loss of dynamics from compressed MP3s I think. 

It does depend at what quality the MP3 has been encoded at but at the kind of settings most people (me included) use for portable devices with comparatively lo-fi in ear 'phones you'll probably hear how lossy the encoding is when listening to the same file on a higher fidelity system.  The proof is in the pudding: play a CD and a ripped version of the same recording and flip between them; if you can't hear a difference then there's nothing to worry about and if you can, how much does it bother you?  I really do hear the difference, especially on more orchestral, piano or vocal based tracks so if I'm going have a "proper listen" to something then I'll use the CD.  If I'm just putting on some music to listen to while I do something else then I'll probably use my iPod rather than rummaging through the CD cases.  Horses for courses really.

[MDV]

Depends mostly on the impedence of the HP. PC150s are 32ohms and can be driven by anything.

Some higher end headphones need it. Some dont but benefit from it, some dont need it at all.

This is lots of headphones and what the people on headfi think needs an amp and doesnt

http://www.head-fi.org/forums/f4/headphone-buyers-guide-271258/