[sonicm]

Okay, I think I asked this once before, but I got mixed responses and asked it in a different way. But I still don't understand. What exactly does an amp do? Wikipedia says "The essential role of this active element is to magnify an input signal to yield a significantly larger output signal." But if that's how it works, then wouldn't it not matter what amp I use as long as I have a amp?

Also, I've heard multiple times people talking about how their headphones sound great through their amps, except their amps go though a chain that's already amplified(eg; ipod shuffle out -> headroom micro)
Shouldn't that do absolutely nothing other than make it louder?

 

[George Chronis]

Yes, in general, an amp will make the input signal louder. In the process, there is other things that are going on. It's not a linear relationship between input signal and output signal (that would be ideal). Some amps will output higher volume bass than treble, some will introduce noise, some will distort while they are all designed to amplify. Some headphones will need higher amplification, some lower, that's why an ipod won't work very well with the K701 or the HD650, even though it's amplified. It's just not amplified to the right level. The wikipedia definition is in theory. The way amplification is happening in practice is not absolute though. Hence all these amps and this forum.

 

[Spareribs]

Another thing, amps look cool too. Besides the warm and natural sound of tube amps, an enhancement that is more than just mere loudness, I adore the look of those bulbs. They light up when the room is dark and remind me that something is alive and burning as I am listening. Hence, I am in awe of something that lights up.

 

[mminutel]

Each amp has an Operational Amp (OPAmp). It is the single most influencial part when it comes to changing the sound. Solid state that is, tube amps are different. You can interchange most amps and each chip has a different sound. Some chips add more bass, some add more treble. Half of the fun is hearing how the sound changes with the OPamps. Yes it will make it louder, but that isnt really what they are for. Not for me at least.

 

[sonicm]

So it does more than just make it louder, it adds its own sound signature, ect;

Now I have a sr-225 and have heard many times that it's a lot better with an amp. Does this mean that whether its 'lineout>*amp*' or 'shuffle headphone out>*amp*', it'd have the same effect on the sound and would make it sound better for my grados?

 

[vilg]

The answer to your question is a big no. When amplifying a signal you want to amplify a signal that is as clean as possible. When going through your shuffles amplifier, which is total garbage just like the internal amplifier of any portable mp3-player, you will add noise/distortion which will also get amplified by your external amplifier. This is obviously not what you want. As far as I remember you really can't get a lineout of any kind from a shuffle (excuse me if I'm mistaken), so my advice would for sure be to get another source before considering an external amplifier.



Quote:

Originally Posted by sonicm /img/forum/go_quote.gif So it does more than just make it louder, it adds its own sound signature, ect; Now I have a sr-225 and have heard many times that it's a lot better with an amp. Does this mean that whether its 'lineout>*amp*' or 'shuffle headphone out>*amp*', it'd have the same effect on the sound and would make it sound better for my grados?

 

[JSTpt1022]

Quote:

Originally Posted by mminutel /img/forum/go_quote.gif Each amp has an Operational Amp (OPAmp). It is the single most influencial part when it comes to changing the sound. Solid state that is, tube amps are different. You can interchange most amps and each chip has a different sound. Some chips add more bass, some add more treble. Half of the fun is hearing how the sound changes with the OPamps. Yes it will make it louder, but that isnt really what they are for. Not for me at least.

ALL amps do not have opamps. These are generally used in portables and electronics for which the headphone amp is a secondary concern. Just wanted to clear the air there. Now I'll step aside and let someone more knowledgable chime in.

 

[Awk.Pine]

Quote:

Originally Posted by sonicm What exactly does an amp do?

An amp is supposed to take a low-power ("line level") signal and increase the signal to be powerful enough to drive the speakers (in headphones or otherwise). In theory, amplifiers are completely transparent; the question is whether they are powerful enough for your needs. For instance, driving a headphone will require less power than driving home speakers, which will require less power than a rock concert's cabs. Too little power will sound bad and may well harm both the amp and the speaker.

Some people believe that the quality of modern amplifier designs, though diverse, meet this transparency theory: any two well-designed, sufficiently powerful amps will sound identical at matched levels. The guiding questions then are (1) how much power is needed, (2) ease of use, and (3) quality of construction. I'm in this camp, as there is objective evidence in its support and none to the contrary; this makes it easy to purchase amplification equipment, but makes irrelevant many of the otherwise interesting discussions here.

Some people believe that modern amplifier designs are not yet sufficient to be transparent, and that different amps change the signal enough to produce audibly different outputs. Much discussion ensues.

Every portable music player comes with an internal headphone amplifier. Some headphones require more power than these amps can provide; another amplifier is then required. "Headphone amp" usually refers to such an additional device, which usually also have volume controls although this is not technically necessary to be an amp.

Quote:

Originally Posted by vilg /img/forum/go_quote.gif When going through your shuffles amplifier, which is total garbage just like the internal amplifier of any portable mp3-player...

Woah there. Take a look at Bill Machrone's Quantifying Digital Audio Player Performance. Several years ago, this PC Magazine columnist bench-tested portable MP3 players. "This is the iPod Shuffle. The square wave is just about perfect--the overshoot might be heard as a small amount of harmonic distortion, but is immaterial. ... With earbuds, the iPod Shuffle's signal looks darn near identical to the no-load signal. I checked and rechecked this result because I couldn't believe my eyes. The iPod Shuffle sounds great, with a solid low end, and no need for bass boost."

I don't know about the second generation of Shuffles, but the first Shuffle has, as far as I know, the best internal amp of all iPods. I'd take a 1G Shuffle -> amp -> headphone over any other iPod -> amp -> headphone anyday, if the question were one of sound quality. Still, you are right to be reluctant to amplify an already-amplified signal, if only to avoid bulk and waste; the separate amp is only required if the built-in amp is insufficient to drive the headphones used; the worst-case scenario is that the second amp will amplify not only the signal but the noise of the first amp.

Quote:

Originally Posted by sonicm Now I have a sr-225 and have heard many times that it's a lot better with an amp. Does this mean that whether its 'lineout>*amp*' or 'shuffle headphone out>*amp*', it'd have the same effect on the sound and would make it sound better for my grados?

Grados are known for having low electrical resistance, which requires more current from the amplifier to drive. (The SR-225 drivers are nominally 32-ohms; my headphones are 100-ohms.) It is quite believable to me that the higher-end models, in which I include the 225, may require enough power to warrant an amp. If your Shuffle is insufficiently powerful to drive your SR-225's--which is likely the case, particularly if you listen at loud levels--then an additional amp will produce better sound and avoid damaging the 225's.

 

[sonicm]

Quote:

Originally Posted by Awk.Pine /img/forum/go_quote.gif An amp is supposed to take a low-power ("line level") signal and increase the signal to be powerful enough to drive the speakers (in headphones or otherwise). In theory, amplifiers are completely transparent; the question is whether they are powerful enough for your needs. For instance, driving a headphone will require less power than driving home speakers, which will require less power than a rock concert's cabs. Too little power will sound bad and may well harm both the amp and the speaker. Some people believe that the quality of modern amplifier designs, though diverse, meet this transparency theory: any two well-designed, sufficiently powerful amps will sound identical at matched levels. The guiding questions then are (1) how much power is needed, (2) ease of use, and (3) quality of construction. I'm in this camp, as there is objective evidence in its support and none to the contrary; this makes it easy to purchase amplification equipment, but makes irrelevant many of the otherwise interesting discussions here. Some people believe that modern amplifier designs are not yet sufficient to be transparent, and that different amps change the signal enough to produce audibly different outputs. Much discussion ensues. Every portable music player comes with an internal headphone amplifier. Some headphones require more power than these amps can provide; another amplifier is then required. "Headphone amp" usually refers to such an additional device, which usually also have volume controls although this is not technically necessary to be an amp. Woah there. Take a look at Bill Machrone's Quantifying Digital Audio Player Performance. Several years ago, this PC Magazine columnist bench-tested portable MP3 players. "This is the iPod Shuffle. The square wave is just about perfect--the overshoot might be heard as a small amount of harmonic distortion, but is immaterial. ... With earbuds, the iPod Shuffle's signal looks darn near identical to the no-load signal. I checked and rechecked this result because I couldn't believe my eyes. The iPod Shuffle sounds great, with a solid low end, and no need for bass boost." I don't know about the second generation of Shuffles, but the first Shuffle has, as far as I know, the best internal amp of all iPods. I'd take a 1G Shuffle -> amp -> headphone over any other iPod -> amp -> headphone anyday, if the question were one of sound quality. Still, you are right to be reluctant to amplify an already-amplified signal, if only to avoid bulk and waste; the separate amp is only required if the built-in amp is insufficient to drive the headphones used; the worst-case scenario is that the second amp will amplify not only the signal but the noise of the first amp. Grados are known for having low electrical resistance, which requires more current from the amplifier to drive. (The SR-225 drivers are nominally 32-ohms; my headphones are 100-ohms.) It is quite believable to me that the higher-end models, in which I include the 225, may require enough power to warrant an amp. If your Shuffle is insufficiently powerful to drive your SR-225's--which is likely the case, particularly if you listen at loud levels--then an additional amp will produce better sound and avoid damaging the 225's.

well actually I was just using shuffle as an example because I saw someone who used that set up

I really wanted to know because I was wondering if my Audigy 2zs and sr-225 would benefit from a new amp.
Looking at it now, I don't think my Audigy 2zs even has a line out, though the Internet says it does, all of the ports either output something else or change when I change the volume. Does anyone know for sure whether or not they do?

 

[PhilS]

Quote:

Originally Posted by sonicm /img/forum/go_quote.gif But if that's how it works, then wouldn't it not matter what amp I use as long as I have a amp?

Because different amps sound different, although some assert otherwise.

 

[EdT]

Heres a simple answer to your question, do you really need an amp ?

Heres a test, listen to the earbuds that came with your Shuffle and noticed where the volume is set that you find comfortable, now without turning off the Shuffle take off those earbuds and plug in your headphone, is the volume the same loudness or is lower ? if it is lower than an amp will help in boosting the signal.

On my set-up up using Grados with a PC soundcard is loud enough for me to not use an amp.

 

[Cousin Patty]

I thought it has been discussed time and again that the purpose of an amp when used with headphones is not to make them louder, but to increase dynamics, bass response, soundstaging, tonality etc... in other words the amp brings the headphone closer to its full potential.

For example, the HD595 can be driven to loud levels out of just about anything, where as the K701 is more power hungry and so in order to achieve the above qualities, an amp is necessary.

 

[upstateguy]

Quote:

Originally Posted by sonicm /img/forum/go_quote.gif Okay, I think I asked this once before, but I got mixed responses and asked it in a different way. But I still don't understand. What exactly does an amp do? Wikipedia says "The essential role of this active element is to magnify an input signal to yield a significantly larger output signal." But if that's how it works, then wouldn't it not matter what amp I use as long as I have a amp? Also, I've heard multiple times people talking about how their headphones sound great through their amps, except their amps go though a chain that's already amplified(eg; ipod shuffle out -> headroom micro) Shouldn't that do absolutely nothing other than make it louder?

Hi Sonicm

The function of a headphone amp is to provide an excellent place in which to store your disposable income. If you ask too many more questions around here, you will find yourself agreeing with me.

Regards

USG

 

[Awk.Pine]

Quote:

Originally Posted by sonicm /img/forum/go_quote.gif Looking at it now, I don't think my Audigy 2zs even has a line out, though the Internet says it does, all of the ports either output something else or change when I change the volume.

I don't know about your Audigy, so my suggestion is to look at what sort of use the manufacturer intended each output for. Changing volume doesn't strictly mean that it isn't a line out; a pre-amplifier's output is at line level, but changes in volume. If the output is a 1/8th-inch minijack designed to be plugged into a powered speaker system, I'd consider it a line out.

The difference, here, between a line-out and an amplified-out is the sending device's impedance. Correctly matched connections will have a low output impedance relative to the next device's input impedance; when output impedance is close to input impedance, nonlinear distortion (bad sound) will result. For example, my preamp's output impedance is 100 ohms, while its input impedance is 18,000 ohms; the 100-ohm output won't result in nonlinear distortion on an 18,000-ohm input. However, if that same 100-ohm output was connected to my 100-ohm headphones, distortion would certainly result.

As I understand it, your main reason for wanting a line-out, rather than a headphone-out, is to avoid unnecessary circuitry--such as volume controls--that may degrade sound quality. In a modern sound card, my guess is that everything up until the final output is digital--that you don't have degrading analog circuitry to worry about. Larger concerns are electrical noise, etc.

Quote:

Originally Posted by EdT /img/forum/go_quote.gif Heres a test, listen to the earbuds that came with your Shuffle and noticed where the volume is set that you find comfortable, now without turning off the Shuffle take off those earbuds and plug in your headphone, is the volume the same loudness or is lower ? if it is lower than an amp will help in boosting the signal.

Here's a disproof of your method: take an amplifier you know to be powerful enough, set it to a given volume level with one pair of headphones, then switch in another pair at the same amplifier level. The volume will change, especially if you're going from earbuds to a circumaural set.

 

[Filburt]

Quote:

Originally Posted by sonicm /img/forum/go_quote.gif Okay, I think I asked this once before, but I got mixed responses and asked it in a different way. But I still don't understand. What exactly does an amp do? Wikipedia says "The essential role of this active element is to magnify an input signal to yield a significantly larger output signal." But if that's how it works, then wouldn't it not matter what amp I use as long as I have a amp? Also, I've heard multiple times people talking about how their headphones sound great through their amps, except their amps go though a chain that's already amplified(eg; ipod shuffle out -> headroom micro) Shouldn't that do absolutely nothing other than make it louder?

Amps accomplish a few things, some of the functions needed more, or less, depending on the equipment used. Amps do voltage gain (increase signal amplitude), and amps provide current needed to drive the load (such as headphones). What getting an external amp can provide is something which does a better job of this than the internal headphone out of your device, either by providing more gain or current, or often times more importantly better damping and recovery. You can get less distortion if you use an amp, but not just any amp is going to necessarily give better performance, although you'll probably at least get different performance (which probably often is interpreted as better, anyhow) much of the time.

If you're interested in getting involved in this hobby, I recommend seriously investigating the merits of various options, on various forums (e.g. don't limit yourself to one forum for information). I'm happy to help as well, but independent research can be valuable both for making educated decisions as well as learning about these devices, which I think is worthwhile if wishing to get involved with this hobby.