Why do I even need an amp?

[minhbo]

There are plenty of posts on this forum on which amp to buy, or this amp vs. that amp etc... but I couldn't find any on why you actually need an amp.

I've read that headphones having a higher impedance are harder to drive. Which I take to mean that it needs a stronger signal to power them to higher volumes. An amp here would obviously help.

But what about headphones that have lower impedance and is already loud enough without amplification? Why would you need an amp in this case?

 

[finbad]

You may not; Or a Boosteroo may suit you too

/Further reading upon search, "is always the best answer"...

Enjoy~

 

[cotdt]

without an amp, you won't be able to hear anything.

 

[MetalManCPA]

I've found out purchasing (3) lower-priced amps [PA2V2, MiniBox-D, MiniBox-E] that an amp does imptrove the overall sound by adding punch at both ends, BUT based on my (3) amps and what I've read here, that each amp provides it's own unique sound signature. That is the big problem, because unless you can buy every amp on the market and test them, then you may never know if you have the amp that best fits your musical listening needs.

Headphones, amps - confusing, and hit or miss. Price doesn't necessarily reflect your own personal satisfaction.

 

[hugz]

first you have to understand that anything you plug your headphones into has an amp built in. if you plug it into your ipod then you're actually plugging it into your ipod's amp.

so the REAL question is "why would i need ANOTHER amp?"; and there are two main reaosns
1) the original amp may not provide enough power. even if it seems to provide enough volume, this doesn't mean that you actually have enough power. consider that some parts of the song may be louder than othert parts. the individual drum beats may be lots louder than the singing. Thus, although the amp seems to provide sufficient volume for *most* of the song, it is actually running out of power on other bits. you may not notice this normally, but when you upgrade the amp to something more powerful it will become apparent

2) this is the more important reason in my opinion (at least for easy-to-drive headphones). The original amp may be cheap and bad. it may take away lots from the quality of the music. thus, you need a new amp purely to avoid the old one. you want an amp that wont damage the music, like most cheap amps would

It's important to connct an external amp to a line-out. a line-out is an output which skips the (cheap) inbuild amp. on something like the ipod it is on the bottom in the data connection thingo (i think). on receivers it tends to be on the back

also, please search

 

[Elephas]

Hello, welcome to Head-Fi.

Both high and low impedance headphones benefit from amplification. Many low impedance headphones sound better with high current amplifiers. The purpose for using an amp is better sound quality, which includes listening at ultra-low volume to very high volumes (for brief periods, to protect your ears).

The benefits include better details, more precise imaging, a larger and more coherent soundstage, better sense of air, better notes separation, improved and more realistic tonality, tighter and more textured bass, smoother sounding midrange, better defined attack and longer decay of notes, etc.

Besides the headphone and amp, other parts of the system also affect the sound, some more than others. The source is very important, and can sometimes be the key component in a system.

Cables and power may or may not contribute to differences, depending on the listener, the system and each individual component.

 

[minhbo]

Ok... I see now. Thanks for the detailed replies.

 

[augustwest]

"But what about headphones that have lower impedance and is already loud enough without amplification? Why would you need an amp in this case?"


If loudness (volume) is all you need, then an amp may not be required.

Most get an amp to enhance the quality of the sound, not for more volume.

- augustwest

 

[jcn3]

as was mentioned, you have to have an amp in the chain. that amp can be in a receiver, in a laptop, or an external one like is discussed on head-fi. whether you need an external amp or not depends on the headphones you are using and your satisfaction with the sound you are hearing.

 

[kramer5150]

Others have pretty much nailed it, so theres not much I can add onther than...."ditto".

IMHO many MP3 players have very poor S/N performance at low impedances. So, while the IEM may be plenty loud enough, its not going to be enjoyable with the hiss and noise.

Adding an amp can cure this completely. Most amps present loads (typically) in the kOhm range to their respective sources, so it alleviates an impedance mis-match condition.

The tricky part is finding an amp that has a gain structure optimal for your particular IEM.... AND colors the sound optimally at the same time. IMHO some of the best amps have high-low gain switches so you can taylor their performance to a variety of cans. On my peg-board cmoy I can switch gain resistors, anywhere from ~3-11, depending on the cans I am using.

Its all about amp/source/can synergy, and not an easy thing to nail down.

 

[nightfire]

Quote:

Originally Posted by kramer5150 /img/forum/go_quote.gif Others have pretty much nailed it, so theres not much I can add onther than...."ditto". IMHO many MP3 players have very poor S/N performance at low impedances. So, while the IEM may be plenty loud enough, its not going to be enjoyable with the hiss and noise. Adding an amp can cure this completely. Most amps present loads (typically) in the kOhm range to their respective sources, so it alleviates an impedance mis-match condition. The tricky part is finding an amp that has a gain structure optimal for your particular IEM.... AND colors the sound optimally at the same time. IMHO some of the best amps have high-low gain switches so you can taylor their performance to a variety of cans. On my peg-board cmoy I can switch gain resistors, anywhere from ~3-11, depending on the cans I am using. Its all about amp/source/can synergy, and not an easy thing to nail down.

S:N ratio, sure.. but equally importantly, a 2nd or 3rd amp stage can also reduce distortion. Since you're reducing the load on the tiny 1st stage (in the iPod or whatever) it's able to produce a more linear/accurate signal; the big transistors/tubes/chips in the external amplifier can reproduce that signal accurately under a much greater load (ie. low impedance phones).

And with high impedance headphones, you may need more voltage than the onboard amp can provide at peak (especially for really crappy players that run at 3-5v). They'll clip when playing high volumes through phones with a very high impedance.

And then there's reserve capacity. The capacitors feeding a tiny onboard chip amp may drain during heavy bass passages, causing a slight voltage drop. This lack of "stiffness" in the voltage can cause bass notes to sound empty/distorted (after the initial slam) because the volume drops slightly after the attack.

In short, external amps kick ass.

If you ever want a really clear demonstration on how external amps help sound quality, wire up your iPod's headphone out to a standard stereo speaker, and crank the volume (but don't do it for long as they aren't meant to handle that kind of load).

The exact same thing happens with headphones, though to a much smaller extent.

 

[minhbo]

Thanks guys for all the responses, they've been very helpful. I can see how an amp would improve sound quality now. I always just thought that if it was loud enough, then what's the point of an amp.

You've piqued my curiosity now, I think I'll go and do a little more research on amps.

 

[a shovel]

impedence? senns have more than double the impedence of the akgs and yet the akgs are much more power hungry. Grados may have only 60 ohms but they still need plenty of juice. Only thing that doesn't need an amp are

32 ohm 100+ sensitivity stock junk that come bundled with portables nowadays and which internal headphone amp on any portable player is designed for.

Nobody designs an ipod or iaudio for people to use senns akg, beyer, or even grados for that matter to be used with them...

 

[nightfire]

Quote:

Originally Posted by a shovel /img/forum/go_quote.gif impedence? senns have more than double the impedence of the akgs and yet the akgs are much more power hungry. Grados may have only 60 ohms but they still need plenty of juice. Only thing that doesn't need an amp are 32 ohm 100+ sensitivity stock junk that come bundled with portables nowadays and which internal headphone amp on any portable player is designed for. Nobody designs an ipod or iaudio for people to use senns akg, beyer, or even grados for that matter to be used with them...

Impedance has nothing to do with power requirements, only current requirements. Power (voltage * amperage) requirements are dictated only by sensitivity/efficiency (measured in dB/W).

ie. an 8 ohm loudspeaker requires much more power and current, but may actually run at the same voltage level as a headphone.

 

[Logistics]

Quote:

Originally Posted by nightfire /img/forum/go_quote.gif Impedance has nothing to do with power requirements, only current requirements. Power (voltage * amperage) requirements are dictated only by sensitivity/efficiency (measured in dB/W). ie. an 8 ohm loudspeaker requires much more power and current, but may actually run at the same voltage level as a headphone.

Maybe shovel was suggesting that even though the akg's have a lower impedance which will allow the IC to typically supply more power for a given voltage supply, perhaps they are low sensitivity and require even more power to match the level of the senns? Suggesting the same thing for the Grados? I don't know because I'm not familiar with them.