okay , I be a earbud geek . I own higher-end product from Ety , Shure , Ultimate Ears and even Senn in the bud category . always on the lookout for a good efficient earbud that do not absolutely require a separate headphone amp for decent sound . the ie7 from Senn sound pretty good plug directly into my iPhone 4 . at home I do not have those limitation . I use the hd650 with they original cable -- I know there be some mighty fine upgrade out there but have not try they . this cable run nicely from the side table where the phone and amp live to my inherit Eames chair . Heaven . 3 year ago , I build my own SET tube amp , impedance match and bias adjust specifically for the hd650 . I have have these phone for go on 9 year now and they have never sound better . for a long time I be run they with a Creek amp and that setup by the way sound very , very good . if you have these and a Creek obh-11 you have better sound than 99.9 % of human . be happy . I be , but my trusty Creek get lose in a move . never be satisfy , I begin my search for something that cost less yet sound way better than the Creek . at this point you be in DIY territory . if you be good with electronics , can read a schematic and can do a professional solder joint , then you too can learn enough to build a great sound headphone amplifier . Mine cost I about 65 buck in part and a bit more than that in good audiophile quality tube . it run very hot , and it make the bass just jump off the hd650 . there be very good solid state headphone amp for the 650 , and musical Fidelity make a great tubed output stage that will take the edge off a lot of solid state preamp . so you can get wonderful enjoyment out of this set of can even with a solid state amp section . but the hd650 be flat out make to be drive by tube . you have never hear something so balanced , smooth , non-fatiguing and yet with authority up and down the spectrum come through something attach to you head -lrb- unless you have pay substantially more -rrb- . I lose my Creek amp , spend a few week source plan and part , get a buddy to help I cut , smooth , weld , powdercoat and drill my chassis , then spend a couple of night put everything together , switch resistor and pot to balance the sound , adjust bias and set up for the high end of the hd650 's rate input voltage , clean the silver contact , and set up . since then I have burn out a tube and replace the pair with a different-sounding pair . not much , but definitely more treble without sacrifice that sweet smoothness that be tube gear 's utter lack of odd-order harmonic distortion . when you clip this thing it still sound nice . it be hard to clip at anything like tolerable listening level , but there be some Floyd track that make any amp\/speaker combo nut , and also some hi-fi organ recording that will put you gear into shutdown if you try to play they at actual volume level . in situation like that , the 650 have be pretty well-behaved since switch to tube . with solid state amplification you feel like you might break they if you do not immediately cut the volume under some circumstance , but this setup give I more volume with less stress on the can . I have reach my own peak of happiness with these headphone . I know there be even higher mountain out there to climb , but I have no desire to even try . the hd650 be a stone cold bargain in headphone consider the sound it can deliver . I listen to a lot of choir and small combo jazz on these , as well as my sister and brother-in-law 's piano recording -lrb- they be both work concert pianist as well as music educator -rrb- . so once in a while I get a new piano piece on a sd card in the mail -- the past couple year it have be mostly Ravel so I guess I be learn to like Ravel . brother-in-law always convert live to Apple Lossless use the good mic and generally good acoustic and electronics in the university 's recital hall . musician can be picky about they record sound . iTunes spit it out to the iPod Nano which have surprisingly good sound use a Russ Andrews interconnect -lrb- inexpensive and highly recommend for good sound breakout from Apple product -rrb- . the iPhone sound fine as well , but I think the Nano sound better . the look of this setup be just fantastic as well . iphone\/ipod with its up-to-the-minute tech and styling , hook up to my homebuilt tube amp , design to evoke in miniature the great Marantz tube amp of the past . with a gorgeous pair of hd650 next to it . the one thing I would like be a nice charge dock like the one Arcam make with a remote . the Russ Andrews cable be plenty long enough to not need a remote -- I can just hold the device in my hand and operate it without get up , and the Arcam dock will not sound any better . but the cable still will not charge the device . the bottom line of all this gear-bragging , the reason why I go into such detail about the setup I use , be this : all of it be design around my sennheiser hd650 phone . they be the basis for all the effort I put into the rest of it -lrb- okay , that and save significant money over just about any decent retail headphone amp -rrb- . I should get one of those little `` Works with iPhone '' sticker and put it on my tube amp . if the hd650 ever break , I will probably buy another one just like it , unless somebody can show I a less expensive option that sound better -- which I doubt . one of the great bargain in high fidelity . if you want great sound and can not afford thousand of dollar in amp and speaker , you can get great sound -- privately -- with these can and a minor investment in a good tubed headphone amp or even a good solid state one . when I buy these , you could get they all day long for $ 350 and I get they on sale at $ 290 . you do not see those price today . I figure I be into my current setup -- ipod interconnect , amp and headphone -- for under $ 500 . you will pay more today , but there be simply no cheaper way to get this kind of great sound . period .