[tf1216]

KillerPotato, I think I see where you question is stemming from. You understand an amplifier's purpose but you are not considering the numerous factors that are involved in an amplifier design.

Many have already commented on the amplifier's job of adding both voltage and current gain. How well an amplifier does it's job of voltage/current gain depends on the design.

What happens is the load on the amplifier changes versus frequency and each amplifier will handle the load differently. This is why some amplifiers are so expensive. Designers decide to cut less and less corners in the design so the amplifier can handle any type of load without audible differences. That is a really simple way of explainging things.

Also, different approaches are taken in designing amplifiers that add a certain character to the audio signal. There are differnt output devices, different means of filtering, differnt approaches to amplifying signals, different ways to supply power, and so on.

 

[dura]

There is a difference listeing unamped to a DAP or a PC. My desktop is able to drive f.i. my HD485 effortlessly, my DAP's aren't, there I really need an amp.

 

[Podster]

If your a non believer don't spend the money

If you think the explinations provided have swayed your thinking get a small portable with DAC since you do laptop listening with the option to travel with better sound!

 

[mchang]

Moving up from unamped (Mac Mini) to low-end amp (Go-Vibe v5) to higher-end portable (Pico) to mid-end desktop (GLite), here is what I've most noticed with my HD-650:

- soundstage (sound increases from being inches away to sounding like in a room or larger)

- instrument separation ("oh, those are the guitar notes; there are the piano keys; and there's the bass guitar -- it's not just all one blob")

- details ("wait! there is a second bass line I didn't hear before. oh, i just heard the guitar player's fingers skim the string")

- tighter bass (instead of "poof poof" for a bass line, it sounds like "BUMP BUMP!")

===

Less (but often still easily) noticeable for me are:

- changes in amount of treble, mid, bass in the sound signature

- speed (which I think most describe as attack and decay of each note)

 

[pretzelb]

Quote:

Originally Posted by oicdn /img/forum/go_quote.gif Grado's are a perfect example. Grados CAN be run to loud leaves out of an iPod, but they're not driven "PROPERLY". Just get something like a Hornet and the difference between your HP out and the line out to Hornet will be a HUGE difference and it will definitly open your eyes...

My experiments with amps was the Grado SR60 and the pa2v2. Both are entry level but with line out from my iPod I could hear a very nice improvement. I could only imagine how much better it gets with an upgrade to headphones and amp.

Can I suggest a free test?

Try going to a place that sells car stereos. If I remember correctly they have setups where you can easily add or subtract an amp to the configuration. Best way to hear the difference is find a setup where you can easily add an amp. With just a decent set of speakers and a helpful clerk it should be something you can do in 10 minutes.

 

[sejarzo]

One of the major reasons to use an amp with 300 ohm cans is that they really do need voltage, rather than current, to properly handle peaks.

Disclaimer: the following applies to peak levels. Please do not think I am in favor of listening at an average level of 104 db SPL......but even in classical recordings, there are peaks in that range when one is listening at a significantly lower average SPL.

Based on Sennheiser specs, it takes about 1.22 Vrms to drive 300 ohm HD600's to 104 dB SPL, but only 0.22 Vrms to drive 50 ohm HD595's to that same level. The current requirement is actually 4.5mA for the HD595 at 104 dB SPL, and 4.1 mA for the HD600. Overall.....yes, the HD600 certainly needs more power--about 5 mW versus only 1 mW for the HD595, but it's really due to the voltage requirement, not the current requirement.

Here's why driving 300 ohm cans from a DAP isn't the best option, though. I don't own one myself, but my daughter's Zen has only a 3.7V rechargeable battery, and I presume that's common. To drive HD600's at 104 dB, the peak voltages in the waveform are actually (1.22 Vrms * 1.414) or +/- 1.72V. That 3.7V from the battery is split to form + and - rails, and so the rails could never be higher than +/- 1.85V when run from such a battery.....not considering other losses in the circuitry. I don't know what opamps are used in DAP's, but it appears that not many can run so close to the supply voltage at the rails, or do so without significant distortion.

As far as I've been able to reason, that's why it takes an amp with at least a 9V battery to drive the HD580/600/650 properly.

 

[krmathis]

Its all about sound quality, not sound pressure level!
Which a dedicated headphone amplifier can give you..

But if you don't believe in them, you are more than welcome to save you money for something you believe in.

 

[Drag0n]

If a bicycle hits you at 20mph and a truck hits you at 20mph, they both hit you at 20mph, but which hit you more solidly?

Same with what youre hearing. Sure, an ipod can drive your headphones to 120db of ear ripping sound, but by the time it gets that loud, you havent noticed that the sounds that need solid drive have dropped out some so the sound is no longer flat.

Bass needs a solid support to drive hard so it hits you like a truck (amp) rather than like a bicycle(ipod alone).

Whenever the bass doesnt get enough drive, it still tries to reproduce anyway, which takes power away from other parts of the music and causes distortion or sounds to blend together so they dont sound as distinct.

With the proper amp, the bass can take what it wants and doesnt pull the rest down with it and everything is clearer sounding.

So you can either reach 120db with just the main frequencies and it sounds loud and shrill and hurts your ears.....or all frequencies can reach 120db and it can sound full and cause real movement of the headphone diaphram.

The balance is different with a weak amp. Easier to drive frequencies are louder than hard to drive ones, like using an EQ.

 

[Joelc87]

Ok think of it this way...you know if you have a big appliance turn on at your house ex. A/C unit or clothes dryer and the lights dim momentarily in the whole house. This is because your house's electrical systems have to adjust to the change in current and it takes a moment. In the same way if you have a sudden large change in the dynamics of the music you're listening to, the sound will be compromised in favor for the stronger signal ex. compromising bass for treble or treble for bass. Now while an ordinary sound card won't diminish for 2 seconds it will have distortion because of the lack of power to accurately reproduce all nuances of a complex audio passage. In short a dedicated amp has capacitance or reserve power to maintain constant current regardless of the situation.

 

[chesebert]

If you are a non believer in amp ('believe' is not the word I would use), you should just save your money and spend it on something else.

why set yourself up to be disappointed? have another hobby or spend it on something worthwhile.

 

[bhostinsky]

I was getting ready to post a lengthy response, but Joelc87 hit the nail on the head. If you look at an amp, especially in a home stereo, the largest component is the power supply. If there is not enough reserve power, the whole audio spectrum affected.

You can think of it like a toilet. The water line to the toilet doesn't provide enough water to give it a good flush. Thats why there is a tank, to give it that extra water needed for a good flush. Music is the same way. If you don't have enough reserve, all your left with is crap.

 

[royalcrown]

Gotta love the amount of analogies in this thread. It's been stated before, and it's great advice, so I'll reiterate at the risk of sounding awfully repetitive: if it sounds good, you're set. There's no need to worry about the "potential" you're missing out on, because at the end of the day the amp really only gives you that last 10% of the sound. Even at the ultra-high end, there's always some "potential" sound that you'll be missing, and thus it'll never end. Many people on this forum (not naming anyone in specific, just the general "mood" of the forum) will overstate the difference an amp can make. The difference between unamped with a quality source and amped with the same source is not the difference between a bad and good pair of headphones. The difference is much subtler and though it may be worth it depending on your preferences, it's hardly a "bang-for-your-buck" scenario.

Now, aside from the value aspect of an amp, to answer your question: why do amps make a difference? Say you have a 1 watt amp, driving loudspeakers with an 86db sensitivity (gah, I know, more analogies, but since phones and speakers are so similar, it's a bit more apt for comparison's sake). Assuming you get very close to the speakers, you may hear some pretty cool sound. However, two things happen at this point.
1) you're so close to the speakers that you can't discern a true soundstage from the speakers. Granted, this example isn't necessarily 1:1, but if you listen to music distortion-free (which rarely occurs, but given the assumption), unamped it would be so quiet that you'd have to strain your ears, thus making it harder to discern subtleties.
2) Say you want to step back from the speakers to get a soundstage (or in the case of headphones, crank the volume a bit to discern the quiet parts of a song). At this point, ALL of the musical information passing through the song much reach within the headroom given by the amplifier. In other words, at this raised volume, some parts of the song may sound fine, but as soon as a loud section comes in, it will peak at a level beyond 1 watt. Granted, the volume will still be there, but the wave will be so clipped that it will distort, which is less than optimal.

Now, the million dollar question, with an answer that's very personal for each person, is whether or not reducing/eliminating that distortion is worth plunking down x dollars for. That leads back to the first paragraph again, which leads full-circle. When I first got my amp, I was hoping for a truly night-and-day difference. Little did I know how abused that term is. Going from an HD-280 to a Beyerdynamic DT880 had a MUCH larger difference than from unamped to amped. Over time, I came to appreciate the subtleties given by my amp, and I do not regret the purchase. That being said, it is what it is - a subtlety.

Yikes, I just realized I wrote a hell of a long post - sorry if it comes off as rambling.

 

[bhostinsky]

"Musical detail, quality and nuances. The dark side are they. Once you start down the dark path, forever will it dominate your destiny."

Everything in audio makes a difference, but "bang for the buck" can only be determined by the individual. That's biggest evil with audio. Will an amp make a noticeable improved difference? Most likely. Be warned, you've already headed down the dark path wondering about the amp. Next is a dac, then tubes, source, etc.

 

[Zephyron]

Quote:

Originally Posted by Drag0n /img/forum/go_quote.gif If a bicycle hits you at 20mph and a truck hits you at 20mph, they both hit you at 20mph, but which hit you more solidly?

Best... analogy... yet!

 

[evilking]

If you've been listening for a whole year without issue then I wouldn't bother.


EK