[ravisurdhar]

Does a headphone amp just increase loudness, or does it do something else too? I've got a pair of SE530s (AMAZING! ) and a pair of UE 5vi's, and both have an absurdly high sensitivity (119 db/mw or something like that). Would an amp really do anything for me? Sources are my MacBook Pro (iTunes, mp3s varying from 128-320kbps) and my iPhone.

 

[Uncle Erik]

I don't know about IEMs (not my specialty), but amps do a lot more than increase volume. Amps have more to do with control. It's the difference between driving a school bus down a twisty road at 55 MPH and driving a fine sports car down the same twisty road at 55 MPH. Same speed, same road, but one does a much better job at it than the other.

 

[Mr.Sh0eWax]

Often times the built in amplifier in your MBP will not be able to deliver the power (in terms current / voltage - someone else can probably offer more details here) that less sensitive headphones require in order to reproduce that analog signal accurately (or to their fullest).

You could try thinking of it as two singers, singing the same score. Even though the music is written the same, a novice singer might not have the breath control and strength in her vocal cords to reproduce the music as well as a veteran singer. Maybe that's too simplistic.

 

[Nuwidol]

 
Quote:

Quote:

^^shut up. why even comment if your just going to say that. But yes amplifying does produce noticeably different sound quality.

 
But how? It's still the same (analog) signal...other than boosting it or changing the EQ, what can an amp do?

Usually when amping you take the sources signal straight from a line out rather than the players own headphone out. this way you bypass the players internal amp & use a clean unaltered signal.

 

[HiFlight]

An external amplifier presents a very high impedance to the output of the player amp or DAC thus helping to prevent alterations of the signal due the varying impedance of the headphones. This change of impedance is a result of the wide variation and complexities of the frequencies presented to the headphones.  

 

[wuwhere]

An external amp has its own clean power supply, it doesn't have to share power with anything else.

 

[Uncle Erik]

 
But how? It's still the same (analog) signal...other than boosting it or changing the EQ, what can an amp do?

 
It has to do with control. Moving a voicecoil and cone is a physical act. Some amps have a better "grip" on that than others do. You can have one amp able to push the cone out, but due to weak power, it might not stop it and move it in the opposite direction as fast as another one can. That comes across as a sloppy sound, sometimes making it sound veiled. Other amps will run out of power during critical passages, and much else.

Also, the amp's ouput impedance curve is very important. It determines how much power is available at certain frequencies and that intertwines with the headphone's impedance curve.

 

[12345142]

Quote:

The search bar is at the top of the page.

Fine, I'll clarify. This question has been asked way too many times. All too often newcomers to Head-Fi immediately start a thread asking their questions, rather than using the search function.
 
OP: try searching for "why headphone amp" in the search bar - I just did. I guarantee you'll find what you're looking for, including several discussions on the same topic that have been started before.

 

[latenlazy]

Quote:

Often times the built in amplifier in your MBP will not be able to deliver the power (in terms current / voltage - someone else can probably offer more details here) that less sensitive headphones require in order to reproduce that analog signal accurately (or to their fullest).

You could try thinking of it as two singers, singing the same score. Even though the music is written the same, a novice singer might not have the breath control and strength in her vocal cords to reproduce the music as well as a veteran singer. Maybe that's too simplistic.

I don't believe it's just that. Some amps distort the signal (especially the built in ones, which I imagine are super cheap). When you get a separate amp you're not just trying to get more power, but also trying to route your signal to a better opamp to reduce or eliminate that distortion.

 

[Mr.Sh0eWax]

Quote:

Often times the built in amplifier in your MBP will not be able to deliver the power (in terms current / voltage - someone else can probably offer more details here) that less sensitive headphones require in order to reproduce that analog signal accurately (or to their fullest).

You could try thinking of it as two singers, singing the same score. Even though the music is written the same, a novice singer might not have the breath control and strength in her vocal cords to reproduce the music as well as a veteran singer. Maybe that's too simplistic.

I don't believe it's just that. Some amps distort the signal (especially the built in ones, which I imagine are super cheap). When you get a separate amp you're not just trying to get more power, but also trying to route your signal to a better opamp to reduce or eliminate that distortion.

Sure, definitely. I didn't by any means try to imply my answer was all encompassing. Sorry if that misled you.

 

[ravisurdhar]

Quote:

 
It has to do with control. Moving a voicecoil and cone is a physical act. Some amps have a better "grip" on that than others do. You can have one amp able to push the cone out, but due to weak power, it might not stop it and move it in the opposite direction as fast as another one can. That comes across as a sloppy sound, sometimes making it sound veiled. Other amps will run out of power during critical passages, and much else.Also, the amp's ouput impedance curve is very important. It determines how much power is available at certain frequencies and that intertwines with the headphone's impedance curve.

Interesting...but that still doesn't change the fact that the signal is going through the DAC and amp in my laptop/iphone *before* reaching the external amp. Whatever sloppyness introduced by those components will only be amplified by the external amp. Besides, like I said, IEMs (and SE530's in particular) have a fairly low impedance and a huge sensitivity...my laptop's amp is certainly powerful enough to drive the SE530s, as indicated by the fact that I never have the volume above 3 (and I assume the volume slider is somewhat proportional to signal power (mW)). I could understand rerouting the signal so the digital signal goes through a different DAC, but once it's analog, there's not much you can do...right?

 

[BlackbeardBen]

Quote:

Quote:

 
It has to do with control. Moving a voicecoil and cone is a physical act. Some amps have a better "grip" on that than others do. You can have one amp able to push the cone out, but due to weak power, it might not stop it and move it in the opposite direction as fast as another one can. That comes across as a sloppy sound, sometimes making it sound veiled. Other amps will run out of power during critical passages, and much else.Also, the amp's ouput impedance curve is very important. It determines how much power is available at certain frequencies and that intertwines with the headphone's impedance curve.

Interesting...but that still doesn't change the fact that the signal is going through the DAC and amp in my laptop/iphone *before* reaching the external amp. Whatever sloppyness introduced by those components will only be amplified by the external amp. Besides, like I said, IEMs (and SE530's in particular) have a fairly low impedance and a huge sensitivity...my laptop's amp is certainly powerful enough to drive the SE530s, as indicated by the fact that I never have the volume above 3 (and I assume the volume slider is somewhat proportional to signal power (mW)). I could understand rerouting the signal so the digital signal goes through a different DAC, but once it's analog, there's not much you can do...right?

No, because if you're driving the external amp with your iPhone's amp, the iPhone's amp is "seeing" the load of the external amp, not the load of the headphones.  So it's not the same - the distortions induced by the load are going to be different, and in essentially every case, lower with the external amp (they are usually a relatively benign high impedance load) than straight to the headphones.

 

[ravisurdhar]

Ah, right, of course. OK, that makes a lot more sense now, thanks! Now, to drop $400 on an amp or not...?

 

[Yoga Flame]

Just to add to what others have already said...

Quote from http://tangentsoft.net/audio/ampweaksource.html:

Distortion goes up as the load on an amplifier goes up. If you add a headphone amplifier, this shifts the load from the source to the headphone amp, lowering the source’s distortion. If the headphone amp is of higher quality than the source’s output stage, distortion can be audibly lower.

 
In other words, it can be difficult for a laptop's weak built-in amp to supply enough power for headphones to sound optimal. But it is easy for the laptop to just pass the audio signal along to an external amp.
 
There is also the issue of hissing for sensitive headphones/IEMs. When I plug IEMs directly into my Creative Xmod, I can hear bad background hiss very clearly. But when I connect the Xmod's line out into my M³ amp and plug my IEMs into that, the hiss is gone. I would have thought the amp would simply amplify the hiss even more right? But I think it's because the amp has high input impedance, so it easily rejects the hiss that my low impedance IEMs could not.

 

[p a t r i c k]

Quote:

Ah, right, of course. OK, that makes a lot more sense now, thanks! Now, to drop $400 on an amp or not...?

Get a second-hand one
 
This way the money will go much further.
 
The most common problem I see with headphones in these forums is people who are using very good headphones with rather mediocre amplifiers.