[MegaBass18]

I didn't know what forum to put this in so I apologize to the moderators if they have to move it.
 
After going through some of the literature in the Sound Science forum, there is quite a bit of skepticism regarding the ability of Amps and DACs to affect sound quality despite many, many testimonials to the contrary.  Let's assume that they don't affect sound quality or provide equalization as a baseline.
 
Is it scientifically possible to change the sound quality of a recording through an amp or do any kind of equalizing?  My admittedly noobish understanding of amps is that they essentially just raise volume and gain.  But the basic design of an amp is not to change sound quality but just to increase volume, correct? Or am I missing something? 
 
Thanks in advance.

 

[bigshot]

If an amp has an equalizer built in, it can equalize.

 

[streetdragon]

amps help to produce a stronger cleaner signal to the headphones, some amps have built in eq's in them like most fiio amps (E6,E7,E07K,E17 etc) almost all amps also have a volume function which can both function to boost or reduce volume of the existing signal. (from lets say 0% to ~200% for the fiio E6) but if you are looking for sq improvement it is highly advisable to buy a new headphone, unless you have an expensive high end headphone already since the price performance ratio of headphones is better than amps especially at lower price ranges

 

[streetdragon]

amps help to produce a stronger cleaner signal to the headphones, some amps have built in eq's in them like most fiio amps (E6,E7,E07K,E17 etc) almost all amps also have a volume function which can both function to boost or reduce volume of the existing signal. (from lets say 0% to ~200% for the fiio E6) but if you are looking for sq improvement it is highly advisable to buy a new headphone, unless you have an expensive high end headphone already since the price performance ratio of headphones is better than amps especially at lower price ranges

 

[skamp]

All DACs that aren't defective will likely sound the same.

Headphone amps can improve sound quality by lowering the output impedance, and provide a flat frequency response with some headphones or IEMs, where high output impedance devices would cause more or less important frequency response variations. The damping factor can be improved as well, for the same reason.

Also, headphone amps introduce varying degrees of distortion, which are inaudible most of the time, except in cases where such distortion is voluntary (e.g. to get a warmer sound). Which ones you like most (which ones offer the best "sound quality") is completely subjective, it depends on your tastes.

 

[PleasantSounds]

Quote:

[..] My admittedly noobish understanding of amps is that they essentially just raise volume and gain.  But the basic design of an amp is not to change sound quality but just to increase volume, correct? Or am I missing something? 
 
Thanks in advance.

 
Your understanding is correct: in a perfect world an amp would just increase the gain of input signal, and do that with 100% efficiency and accuracy. The problem is that pesky less than perfect reality....  
 
Each amp design must balance several factors: performance, efficiency, manufacturing costs, etc. You can get near perfect performance, but it will cost more. You can make it more efficient, but it may not sound as good. Additionally they have to deal with one parameter which is always unknown: the headphone that will be used with it. 
 
Why is it important? Because headphones have not only different impedance - they have different impedance depending on the frequency of the signal. The impact is more or less similar to a car trying to travel up and down hills while maintaining the same speed. 
 
So the sound coloration is more a side effect than a goal, albeit some of these side effects sound better than others and become sought after features.

 

[scuttle]

Any amp is going to "colour" the sound to some degree - which is just what an equalizer does. But what are the odds that an amp will provide exactly the equalization you want? Pretty low! 

 

[bigshot]

It really isn't hard to find amps that don't color the sound.