K701 with no Amp

An amp will increase micro-details and keep separation of instruments intact. You will be able to hear those details with less db. Amps are for more than a louder signal. The slew rate of the signal is improved which helps the 701's large diaphragms stay in control. You can make noise with cheap amps but controlled sound will cost ya more. If your music seems out of focus when listening to loud and complex material, you need an amp.

A powerful amp will also give the bass more weight

I committed the sin of listening to these phones with an iPod as source. Good sound, but you won't get the full breadth of sound that more volume can give you.

I then listened on an iMac with graphic EQ - and it really opened up. A good, compatible amp can do the same magic. Strictly speaking, you don't need an amp - it's just preferable.

But don't expect too much from amping - one person's night & day differences often turns out to be barely noticeable for the other.

I personally liked the K701 quite well (testwise) driven directly out of my Sansa and didn't find the amp improvement jar-dropping.

I think the K701 really benefits from the right synergistic amp.

I would definitely advise against using the K701 without an amp. It really needs good amplification. I mean, if you're happy with it that's great. But you'll see significant improvement if you match it with the right amp.

K701 out of an iPod/other source without amping is probably utilizing something like 20-40% of K701's full potential. Doesn't mean that it sounds horrible like ibuds, no, but it would be kind of a wasted talent sort of situation.

I have a K 702 and I don't use an amp--it's just plugged directly into my laptop. I love the sound and though many here say you need an amp to take full advantage of them, the truth is that it sounds great to me right now.

I originally planned to purchase the 702 first, and then save up some money so that I could buy an amp (and maybe a DAC) for $300-$500 as soon as possible; after listening to my 702 unamped, I decided that I will only begin to even consider purchasing an amp after I get a chance to plug mine into one and hear differences, if any. That way, I can decide for myself whether spending up to double the cost of the headphones for a slight (or large? Don't know yet...) improvement is worth it.

Buy an inexpensive tube amp and see what the difference is. My Little Dot mk 11 has incredible midrange and great bass. The highs are really good. The magic of tubes will help reveal what the 701 are capable of.

Arctia, if you are satisfied with the Auzentech Prelude it's great...and is the end of part one. If you want to check out part two, you can try some top amps, I can recommend you to the SPL Phonitor. After you get the chance to listen to the Phonitor you'll know better how satisfied you are with part one.

Acix, that is some expensive kit to be pushing to someone new to the whole amp thing. I agree that its better to aim high, but that might be a little too high - the Phonitor is probably more at home in a studio than a home listening room. I'm not arguing about SQ - I'm sure its superb - just VFM.

My only contribution to the whole amp thing is that my integrated pushes a lot more air than anything else I own - whether its driving speakers or the cavernous cups on my 601s, that air contains the fine details that we enjoy. It will still do that at relatively low volumes - I usually dont go far beyond 9am or 10 am - while DAPs and cheaper amps will simply work way too hard for very little result with hard to drive cans.

I've got k702s and I too am in love with them.

I've used them in several combos including

iPod->k702
iMac (hp out) -> k702
iMac -> receiver -> k702
iMac ->Audio-Gd Compass ->K702

I found that depending on the amp I used (a couple different receivers and the compass) I got a bit different character. One receiver I use pumps the bass like nothing else, while the Compass is not quite as bass strong, but has great clarity and instrument separation.

At any rate, between amped and not amped I've found that the consistent improvements come in these areas (in no particular order):

clarity of timbre, separation of instruments, EQ, bass response, realism of sound, richness of sound, details.

So, the question ultimately comes down to, how much do you want to spend?
I shelled out for shipping for the Compass and I think it was worth every penny. I think it's definitely worth your while to at LEAST garage sale a receiver to give it a little extra juice.

Using an external headphone amp with the source signal coming from the source's headphone jack, will usually (not always) give very little improvement in SQ, because the headphone jack is a bottlenck in the chain.

So, if you use a true line-out from your source player, that bypasses a built-in headphone jack and its amp section, then, this is what gives the dedicated external headphone amp the ability to do its best work for you, and will give the biggest gains in SQ to your headphones.
This is a basic truth.

Amps aren't about volume per se. They are for getting hard to drive phones working to their capability. The general rule is that low impedance cans (less than 100ohm) can usually drive to most of their capacity without an amp.

There are a few exceptions; the K701/2 are 2 of those; low impedance phones that are pigs to drive properly. Your phones need power from an amp to move the drivers and open up their full dynamic range. Whilst they're not expensive phones, when you add up what it costs to run them properly, they're high end.

Yes, plug them into a PC or iPod and they'll sound pretty good, but they're also running a long way short of their potential, and wasting a fair bit of money.

Yes, there'll be plenty of people here who say they're fine. Most will never have heard them with a decent amp either.

When you add an amp, you need a good source as well, because the 701 and an amp will find the limit of a poor source fairly easily and let you hear any of the bad stuff.