It's hard to imagine what something is like if you haven't experienced it. From time to time someone will set up a cheap rig and insist that spending anything more than they have is crazy and all amps or DACs sound the same, despite people with more experience knowing better. Boomana wrote up an excellent post, in reply to a discussion on amping headphones, the difference between getting sufficient volume and sufficient amping:
I don't know anything about ripple, but I'm confused reading your response to tomb because you seem to be talking about different things. You're talking about loudness, and tomb isn't. Unless I'm misinterpreting your words, you're saying that certain soundcards can drive known difficult-to-drive headphones to sufficient volumes. As far as I know, that point was never in question. I'm not a technical person, so I'll just give an example from my listening experience, so forgive if I'm missing either your or tomb's points, but here's my understanding:
Let's take one of the most notorious hard-to-drive headphones, the K430s. I was certainly able to get sound from my computer soundcard, but not sufficient volume (no, I don't have one of the newer, reportedly more powerful soundcards, and I admittedly know nothing about them), and the sound was thin, flat, and disappointing. I could plug my headphones into the micro amp I had at the time, or even the jack of the Eastern Electric MiniMax cdp I had with better results, but not really. The music was louder, but really unsatisfying, though I could certainly get a taste of the K340s sound signature and the beautiful mids. I bought a Heed Canamp and a Darkvoice 336, which were $400 and $260 at the time (I have no idea what they are now), and what a difference! Not only was I able to get it way past volumes I would want, the sound quality drastically improved at normal, safe listening volumes, and I was suddenly noticing parts in the music (mostly in treble and bass) that I hadn't noticed before. I became aware of imaging, and a sense of where the instruments were placed in relationship to each other, an idea of "soundstage" and depth, etc. that were not present with other, less powerful amps. I had to turn both amps up to a certain volume (a wee bit loud, but not too loud) to hear the music like that, but it was wonderful when I did. I suddenly knew the benefit of more powerful amps with certain headphones.
Jump forward about a year, and I got a SP Extreme Platinum, which I'd bought to drive K1000s single-ended since I didn't have a power amp at the time, and having heard the amp at a meet, I knew it could drive all my headphones. I thought it might be a Swiss Army knife of amps, and it still is my only full-size dynamic amp. Anyway, I plug my K340s into it, and the bass is cleaner, tighter, and with a better sense of attack and decay. That jumped right out at me, but here's the kicker: I could turn the volume down to almost inaudible levels, and every bit of music was presented as fully as it had been with the Canamp and DV, but with those, I needed to have the volume borderline loud to hear it the same. And with the SP, at the same "normal" listening level as with the Heed and DV, the K340s had a more open sound, with much better separation of notes (e.g., can hear individual notes in tympani rolls, not just the roll) and sense of balance from bass to treble (heavier mid emphasis with the DV and Heed).
That experience was the first to teach me that driving a headphone "well" had very little to do with volume. Volume was just one factor, and since that time, it's never been a deciding factor for me when choosing an amp, since most amps can produce adequate volume.
BTW, I ended up using the SP as a preamp to a FirstWatt F1 for the K1000s, and the best I ever heard the K340s was with jp11801's re-terminated to a 4-pin pair, using a K1000 tail and the FirstWatt. Holy moly! These headphones are seriously underrated because they are usually seriously underpowered. Can a decent desktop (DV, Heed) drive them enjoyably? Absolutely! Can it drive them well? That's debatable, but in my opinion the answer is no. Oh...and the SP could definitely drive the K1000s to sufficient volume, but also not drive them well. The K1000s definitely need a power amp to bring out their sound.
Now, I just used those headphones as an easy example, but I've found the same to be true with the HD650s, K701s, and though I sold my HD800s, the limited experience I had with those headphones is pretty much the same.
I don't know of anyone who would tell someone not to enjoy their headphones, if they do, from whatever they're using to drive them. Enjoy! On the other hand, it's also alright to acknowledge that sufficient volume doesn't always equate with being well-driven.
I just want to add that the whole my headphone is loud so it's being driven well argument is in the same category of misinformation of tube amps are warm and lush, and solid state amps are analytical on this board. Just because it's sometimes true doesn't not mean it's The Truth, and in reality, examples proving the opposite are probably more plentiful.
1) If your headphones aren't capable of revealing differences, you won't hear them. Different headphones have different requirements.
2) If you've never had the opportunity to hear a specific headphone with wide variety of amps and sources, not just one or two, you might not believe there are differences, even they exist; and just because a certain headphone doesn't reveal changes in amps or sources (there are many that don't), doesn't mean others won't.
3) Critical listening is a skill that must be learned and honed over time. Back in the late 80s and early 90s I lived with a well-respected record producer, mostly jazz, who even won a Grammy. Being an obsessive nut over every little everything, when working on a project it was 24/7 in the studio and then at home, actually bringing the R2Rs with him when in the mixing and mastering phase. He'd listen on both speakers and headphones around the house, and would sometimes ask me my opinion, saying, "What do you think of this (some ever so subtle change he did with something)?" I couldn't hear what the heck he was talking about until he taught me how to listen, and the truth is that it annoyed me to learn to listen critically. It took effort and concentration and I found it very frustrating at first, but over time (a couple years, not weeks), I learned to hear and distinguish things quickly and clearly that I absolutely couldn't hear before, and even then I couldn't hear what both he and his sound engineer could hear very well. I don't listen critically 95% of the time now because I don't like to, and I'm pretty aware that I've lost some of the skill I had back then.
You can't describe subtle differences in certain colors to someone who is colorblind. It doesn't mean others can't see them, and that they don't exist. Same thing here. I think so many of the disagreements on this board come folks battling over issues with roots in those three areas. At some point you just give up trying to say anything at all.