[Rhum]

I'm looking for some advice on picking an amp, but I think I need more information regarding some definitions that I'm not too familiar with yet before choosing. I'll begin with my situation. I have a pair of HD-600s and I'm in need of an amp as I am currently using my Denon A/V Receiver. In the future I plan to purchase a pair of Oppo PM-3s for more portable listening or just while listening with others in the room. At some point in the future I'd also like to purchase a pair of LCD-3s and/or HE-500s. I'd like an amp that can work well with all of these phones and provide my HD-600s with some warmth. One of my concerns is that a warmer amp will make already warm headphones like the PM-3s and the LCD-3s a little dark. I'd like to have an amp that will make what I already have sound great and scale well with what I'd like to have in the future. At the moment I'd like to spend $500 USD or under, but I'd be willing to consider more expensive amps if it would mean not having to upgrade when I move to more premier headphones like the HE-500s or LCD-3s. I've already searched all over Head-Fi and some recommended HD-600 amps are the Schiit Valhallaz, WooAudio WA3, RKV Mark III and the TTJV Millet 307A. Please recommend these or any other options that would work well with my set up.
 
The second part of this question refers to the definitions and specs that are associated with headphones and amps. I've read a couple threads and other articles discussing impedance, sensitivity and efficiency, but I'm having trouble understanding the definitions and implications of these terms. From what I've read impedance has to do with the power that drives the headphones. Headphones with low impedance are able to be used with less powerful devices and headphones with high impedance require an amp. What are some of the other implications that come along with high and low impedance headphones?
 
Also, I originally thought sensitivity and efficiency were interchangeable terms, but I've come to the understanding that that is incorrect. Can someone please explain the difference between sensitivity and efficiency and how they effect my amp choice and the sound of my headphones? My main concern with these definitions is making sure that beyond having an amp that will fit the sound profile I prefer with my current and future headphones, I also want to make sure the amp is electronically compatible with the headphones I've chosen which range from impedances of 26 ohms up to 300 ohms. Any and all advice is appreciated!

 

[rigodeni]

First of all your asking for an amp that works with all those headphones. Then you also want to pair an amp for a particular headphone. Your obviously confused. Let me clear things up quick and dirty for you. Regarding the terms, don't waste your time on those numbers, figures, and definitions. All of those elements affect how much power you need based on the manufacturer's specific implementation, which varies by manufacturer, and even model. So you can't take these figures at "face value". At the end of the day it means having the volume at 11 o'clock vs 10 o'clock. So let me save you the trouble, just don't go down this rabbit hole.
 
The good news is modern amps handle these variables (impedance, sensitivity, ect.) automatically. Just don't worry about it. In terms of the various coloration certain amps add, it's all subjective. Dark, warm, whatever you want to call it, it's intentional distortion added at some point down the line (usually with tubes). People will hear and describe this distortion differently on different headphones. Higher end headphones like those you mentioned are quite balanced and detailed. Many of them will require higher power than your average cheap amp built into most devices. However, any modern full-size desktop amp in the $100+ range will have enough power, don't concern yourself too much about not having enough power. Remember, at the end of the day it simply means setting the volume at 11 o'clock vs 10 o'clock.
 
I don't usually recommend tube amps, unless they are a hybrid tube+solid state for one reason. They add distortion, which can sound good to certain people on certain headphones, but not on others. Unless you want to go down the rabbit whole of having a separate amp for each headphone your better off eliminating ANY distortion and let the headphone "color" the sound instead of the amp. I like the motto of "The best source is no source" meaning the source should not alter the original signal in any way, besides adding volume. Of course we know this is impossible, but that's the goal. Solid states are also cheaper, lower maintenance, and more compact. Lower end tube amps tend to offer a higher power output than an equally priced solid state, but with a lower SNR (more distortion). Hybrids can give you the best of both worlds, but are more complex and expensive. Choosing tubes or hybrids will severely limit your options because most amps on the market are solid state, and for a good reason.
 
In terms of choosing a particular amp over another, you need to narrow your options by budget and features first. Then get to the specifics of which might sound better with what, which is all subjective by the way. Another rabbit whole to avoid. By features I mean the inputs and outputs, or whether you need a DAC or not. If so, do you need Optical, Coax, or USB or all 3? Do you want it portable, if so is it important to work on iPhone and Android as a DAC? Stuff like this. Until you establish the feature set and budget we can't suggest anything. Judging by the headphones you mentioned I doubt you would want a portable setup, but you get the idea.

 

[Rhum]

  First of all your asking for an amp that works with all those headphones. Then you also want to pair an amp for a particular headphone. Your obviously confused. Let me clear things up quick and dirty for you. Regarding the terms, don't waste your time on those numbers, figures, and definitions. All of those elements affect how much power you need based on the manufacturer's specific implementation, which varies by manufacturer, and even model. So you can't take these figures at "face value". At the end of the day it means having the volume at 11 o'clock vs 10 o'clock. So let me save you the trouble, just don't go down this rabbit hole.

 
Thanks for your insight rigodeni! I guess the main reason I was interested in learning about the terms was because I plan on having headphones with many different impedance levels and I don't want to blow out any of them.
 
The main reason I was searching tube amps is because I want to add some warmth to my flat HD600s. I originally got them as my first set of cans when getting into audio and I wanted something that was worth their price and that would help me learn some more about the details in my music. At this point though, I want some "fun" headphones which is why I've picked some that have a warmer frequency response. I want an amp that will allow me to add some warmth to my HD600s but not make a warm headphone, like the PM-3,  turn dark. I definitely plan to stay away from having an amp for each headphone so perhaps I should expand my options.
 
As for the options I need in an amp I would like an AES input, coaxial BNC and USB. For outputs I would need XLR and 1/4", but they wouldn't need to be balanced. I do not need a DAC, but I wouldn't be opposed to it if the amp I wanted came with it. Lastly, it doesn't need to be portable at all. As you said, most of the headphones I mentioned are not portable so I wouldn't be using them outside of the house. Since I don't do a lot of listening from my phone I can't justify spending money on a portable amp.

 

[Rhum]

Still looking for some advice/recommendations for an amp if anyone has any idea.

 

[PurpleAngel]

Still looking for some advice/recommendations for an amp if anyone has any idea.

 
What is the model # of the Denon A/V receiver?
 
Usually receivers are fairly good at driving 300-Ohm headphones (HD600).
 
What audio do you listen to when using the HD600?
What sources are connected to the Denon receiver?

 

[Rhum]

   
What is the model # of the Denon A/V receiver?
 
Usually receivers are fairly good at driving 300-Ohm headphones (HD600).
 
What audio do you listen to when using the HD600?
What sources are connected to the Denon receiver?

The receiver is an AVR-E300. I don't mind it right now, but I know I have better options.
 
As for the audio I'm putting through it I'm just using FLACs from multiple genres, mainly alternative, hip-hop and edm. All the music is connected through a USB drive I have connected to the USB on the front.

 

[cel4145]

I don't think your receiver has any analog outs (check your manual). So how were you planning on hooking your headphone amp up to it? To the headphone jack? That might or might not work best (not sure). If you have a computer you could connect to a DAC/headphone amp, perhaps that is the way to go.

Then OTL tube amps do not have a low enough output impedance for low impedance headphones. The general rule that is you want the low output impedance of the amp to be 1/8 or less than that of the headphone, or otherwise it may affect dampening and or the accuracy of the frequency response. So for a headphone amp that would be optimal for headphones from 32 ohm to 300 ohms, you'd need to go solid state or hybrid tube/solid state.

 

[PurpleAngel]

  The receiver is an AVR-E300. I don't mind it right now, but I know I have better options.
As for the audio I'm putting through it I'm just using FLACs from multiple genres, mainly alternative, hip-hop and edm. All the music is connected through a USB drive I have connected to the USB on the front.

 
As far as I can tell, you have nothing you can connect an external headphone amplifier to.
You could get a FiiO X1 ($100) or X3 Gen II ($200) and connect an external headphone amplifier to the FiiO.

 

[ProtegeManiac]

Quote:

Originally Posted by Rhum /img/forum/go_quote.gif

I'm looking for some advice on picking an amp, but I think I need more information regarding some definitions that I'm not too familiar with yet before choosing. I'll begin with my situation. I have a pair of HD-600s and I'm in need of an amp as I am currently using my Denon A/V Receiver. In the future I plan to purchase a pair of Oppo PM-3s for more portable listening or just while listening with others in the room. At some point in the future I'd also like to purchase a pair of LCD-3s and/or HE-500s. I'd like an amp that can work well with all of these phones and provide my HD-600s with some warmth. One of my concerns is that a warmer amp will make already warm headphones like the PM-3s and the LCD-3s a little dark. I'd like to have an amp that will make what I already have sound great and scale well with what I'd like to have in the future. At the moment I'd like to spend $500 USD or under, but I'd be willing to consider more expensive amps if it would mean not having to upgrade when I move to more premier headphones like the HE-500s or LCD-3s. I've already searched all over Head-Fi and some recommended HD-600 amps are the Schiit Valhallaz, WooAudio WA3, RKV Mark III and the TTJV Millet 307A. Please recommend these or any other options that would work well with my set up.

 

Well, for starters, it's called an amplifier instead of a warmifier or colorifier for good reason - it's supposed to amplify the input signal to a level that can drive whatever kind of transducer it's designed to drive, not warmify or colorify that input signal. It's supposed to have the lowest THD while delivering current and voltage that can provide dynamic range and as much loudness as you can handle without clipping and distortion. The point is, your electronics (mostly active, but of course there's a reason why in the case of speaker systems some prefer a passive preamp) need to have the flattest signal possible with the amp not distorting on whatever it's driving, and the headphones/speakers are what will provide the coloration, since technically speaking there isn't any with an absolutely flat response from 20hz to 20khz anyway.

 

The second problem here is that due to the wide range of impedance (along with the advantages and disadvantages they come with) some amps aren't that good on certain headphones. Headphones with higher impedance tend to have higher sensitivity, while many lower impedance models tend to have lower sensitivity also. I assume you know speakers enough given you have a receiver, but think of that along the lines of how a fullrange driver with a notch filter and a tweeter covering only the highest treble range in a transmission line box can be powered by a pair of mono "flea" tube amp running fully in Class A thanks to its sensitivity, but a low impedance (4ohm), low sensitivity, multiple driver Dynaudio tower speaker will need a high current amp with a huge power supply.

 

If you can get over the need for warmifying the HD600 then there are a lot of other options for you, since a lot of the warmifying amplifiers tend to be OTL tube amps (note that amps like the Valhalla barely colors the sound at very safe listening volumes) that might not work well on lower impedance headphones. You can just get a relatively neutral amplifier like the Schiit Lyr, which is designed to deliver a lot of power to low impedance headphones but you still get a lot of usable power at 300ohms. There's also  AudioGD Precision 1 or 2 (I haven't heard these but the few reviews so far seem promising) which has a gain setting that works differently - it flips the output level to favor high or low impedance.
 
 

Quote:

Originally Posted by Rhum /img/forum/go_quote.gif

 

The second part of this question refers to the definitions and specs that are associated with headphones and amps. I've read a couple threads and other articles discussing impedance, sensitivity and efficiency, but I'm having trouble understanding the definitions and implications of these terms. From what I've read impedance has to do with the power that drives the headphones. Headphones with low impedance are able to be used with less powerful devices and headphones with high impedance require an amp. What are some of the other implications that come along with high and low impedance headphones?

 

Also, I originally thought sensitivity and efficiency were interchangeable terms, but I've come to the understanding that that is incorrect. Can someone please explain the difference between sensitivity and efficiency and how they effect my amp choice and the sound of my headphones? My main concern with these definitions is making sure that beyond having an amp that will fit the sound profile I prefer with my current and future headphones, I also want to make sure the amp is electronically compatible with the headphones I've chosen which range from impedances of 26 ohms up to 300 ohms. Any and all advice is appreciated!

 

It has more to do with the output impedance of the amplifier, which affects damping factor and the most obvious effect is on the bass - it can either enhance the bass (quantity, not quality - you get it boomier, or as some perceive it, "warmer") or make it non-existent (like using 120ohm+ output impedance headphone outputs on speaker amps to drive Grados). It doesn't really relate to power other than where in the impedance range an amp delivers it's highest output and lowest distortion levels, but like I said above, it's safer to use an amp optimized for lower impedance on a headphone up to 300ohms since the sensitivity can compensate for the lower output. On a good amp even with higher THD at a lower output you'd still need a lot less of that at high impedance when for example the HD600 has a 97db @ 1mW sensitivity rating.

Basically, the output of the Lyr at high impedance would encounter a lot less issues than when you use the Valhalla on a lower impedance load.