[ZBoneCapone]

When do I need one and why? I've read that a DAC really won't alter sound and that amps are only needed if you want more volume. Could someone explain these things to me?  

 

[linglingjr]

A dac is a digital to analog converter:
http://www.head-fi.org/t/201322/what-is-a-dac
 
Dacs are what create the sound.  They are what convert your digital music files from  a series of 1s and 0s into audio signals.  
 
What headphones are you trying to drive? 

 

[urtv]

I have an ES10. Was recommended to get the Creative Sound Blaster Z since it comes with a dac/amp. Would that be enough?
 
And how do I know when a headphone/earphone needs a dac/amp?

 

[ZBoneCapone]

I know what a DAC actually is, I know that it converts digital to analog. I want to know when and why I need it. What type of headphones? How high of an impedance? Those sorts of things. I am going to be driving the AKG K702 65th Anni. edition

 

[Jd007]

DACs do not drive headphones directly (though if you plugged one in it would make sound). They output line level signal which must be fed into another power amplifier (headphone amp, preamp + power amp, integrated amp) to get a signal strong enough to properly drive sound equipment. There are DAC/amp-in-one products, such as some sound cards (Xonar Essence), and some external DAC/amp combos. Give us a budget and we can give you better recommendations.

 

[ZBoneCapone]

Quote:

DACs do not drive headphones directly (though if you plugged one in it would make sound). They output line level signal which must be fed into another power amplifier (headphone amp, preamp + power amp, integrated amp) to get a signal strong enough to properly drive sound equipment. There are DAC/amp-in-one products, such as some sound cards (Xonar Essence), and some external DAC/amp combos. Give us a budget and we can give you better recommendations.

Budget of $100-$150. Nobody has answered my question, though. I know what a DAC is and I know of DAC/amp combos on the market (Fiio E7 for example). What I want to know, what is the requirement for a DAC or amp? Is it a certain driver? Certain coils? A range of impedance? Are there any hard and fast rules? I want to be knowledgeable on this subject as a whole, not just what will work with cans. (Although I do want to know that, too!)

 

[Eric_C]

Quote:

I know what a DAC actually is, I know that it converts digital to analog. I want to know when and why I need it. What type of headphones? How high of an impedance? Those sorts of things. I am going to be driving the AKG K702 65th Anni. edition

 
When do you need a DAC? Always. Same with an amp. 
Both are built into every smartphone, MP3 player. 
You need the DAC to be able to have sound, and you need the amp to be able to hear sound.
 
On Head-Fi when most people talk about adding a DAC or amp, they mean adding an external DAC or amp. The common opinion is that the DAC or amp built into whatever device you have is lousy.
 
General rule for amps (as I've heard it, I don't know the science), is that high impedance headphones need high-voltage amps. Low impedance headphones need high current. 
Ohm's Law is being applied here, I think: V = IR

 

[linglingjr]

everything that plays audio has a dac built in.  your computer has "on board audio" which is a chip built into the motherboard these are typically lower quality and there is interference from other components on the motherboard.  There are no requirements for a dac the higher quality the better.  Amps are different there are solid state amps and tube amps, tube amps produce a warmer (more bass heavy sound) while solid state amps are flat and more neutral.  So when you pair an amp with a certain pair of cans if the cans are known to be bass heavy and you buy a tube amp then it will be bass heavy + bass heavy = terribly bass heavy so usually you want to put cans that lack bass with a tube amp to counter act the lack of warmth and vise versa for base heavy cans. Hope that helped do some searching on what amps people recommend for what cans. 701s that you have are high impedance and hard to drive so you will need a powerful amp.  the 701s also lack bass so they would go well with a tube amp. 

 

[Eric_C]

Quote:

tube amps produce a warmer (more bass heavy sound) while solid state amps are flat and more neutral.  

 
Actually, that's disputed territory. Some people think that amps should always strive to be neutral, some think they should "flavour" the sound.
OP, what is important is to bear in mind that amps are always there to amplify, and that the impedance determines whether the amp should be current or voltage "heavy". IIRC, tubes have better voltage swing. Solid state amps, not necessarily better for voltage or current.
 
For your headphones, look up threads specifically on its amp pairings. There are many threads on your headphone.

 

[Vloeibaarglas]

Quote:

General rule for amps (as I've heard it, I don't know the science), is that high impedance headphones need high-voltage amps. Low impedance headphones need high current. 
Ohm's Law is being applied here, I think: V = IR

 
What, just completely ignore this section of the post.
 
 
Whether you need an amp depends on two things, the impedance (complex resistance) and sensitivity (think efficiency). Impedance is measured in Ohms ([size=small]Ω).[/size] Sensitivity is measured in dB/mV.
 
A headphone is adequately driven (which may not be necessary but most believe that a fully driven headphone is better sounding) when the volume reaches a certain level. 110 dB is a level that I've seen used for this type of measurements (don't listen to your music at this level, it is really loud). You need to supply the headphone with enough voltage (mV) to drive the volume (dB) to adequate levels. 
 
The reason why build in sound cards/portable devices can't power high impedance or low sensitivity headphones is that they can't supply enough voltage at the impedance of the headphone. Most if not everything can supply more than enough voltage at low impedance. At higher impedance, most sources without a dedicated amp will struggle to supply the voltage.

 

[Eric_C]

Wow, I'm sorry my understanding was so wrong it warranted swearing at my post.

 

[Fearless1]

Quote:

.  So when you pair an amp with a certain pair of cans if the cans are known to be bass heavy and you buy a tube amp then it will be bass heavy + bass heavy = terribly bass heavy so usually you want to put cans that lack bass with a tube amp to counter act the lack of warmth and vise versa for base heavy cans.

Huh? 

 

[Seamless Sounds]

Quote:

When do I need one and why? I've read that a DAC really won't alter sound and that amps are only needed if you want more volume. Could someone explain these things to me?  

 
In a studio setting, that DAC becomes even more important than an audiophile setting. The DAC's drivers, specifications, and features are what you want to look at rather than concerning yourself with sound quality. Ideally, a DAC should not "add" its own flavor to the signal. If you get EMI, hiss, or jitter, and it's not mentioned in the specfications, then they're technically flaws or deficiencies (i.e. cheap DAC knock-offs, unshielded parts, roll-offs, etc.). Stay away from companies that don't stand behind their products (I'm looking at you EMU).
 
As for headphone amps, their main job is to amplify the line signal for harder-to-drive headphones. The rest are features, specifications, and aesthetics.

 

[Vloeibaarglas]

Quote:

 
What, just completely ignore this section of the post.
 
 
Whether you need an amp depends on two things, the impedance (complex resistance) and sensitivity (think efficiency). Impedance is measured in Ohms ([size=small]Ω).[/size] Sensitivity is measured in dB/mV.
 
A headphone is adequately driven (which may not be necessary but most believe that a fully driven headphone is better sounding) when the volume reaches a certain level. 110 dB is a level that I've seen used for this type of measurements (don't listen to your music at this level, it is really loud). You need to supply the headphone with enough voltage (mV) to drive the volume (dB) to adequate levels. 
 
The reason why build in sound cards/portable devices can't power high impedance or low sensitivity headphones is that they can't supply enough voltage at the impedance of the headphone. Most if not everything can supply more than enough voltage at low impedance. At higher impedance, most sources without a dedicated amp will struggle to supply the voltage.

 
I feel like I didn't explain this very well...
 
tl;dr version:
Every headphones needs a certain amount of voltage to reach a certain volume. The amount of voltage needed depends on the sensitivity of the headphone. Your amp must be able to provide that amount of voltage at the impedance of the headphone, this part is where integrated soundcards and mp3 players fail.

 

[linglingjr]

Quote:

Huh? 

In other words headphones have a sound signature and so do amps... I worded it terribly but it wasn't that bad.