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Topic: Suggestions for portable headphone amp (Read 11169 times) previous topic - next topic
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Suggestions for portable headphone amp

TL;DR Would it make sense to pair both devices with a Fiio E12 using the standard headphone jack as opposed to the Apple connector/micro USB out.

Longer version:
I have a pair of HD 600's connected to the Headphone Out of my Xonar Essence STX, since 90% of my music listening happens at the computer. I would like to be able to use my headphones with my iPhone 4s and my Nexus 7 (2013) when I am at my parents place for example. The HD 600's have an impedance rating of 300 Ohms (up to 550 Ohms depending on the frequency). Now bear with me since I am a complete and utter newbie when it comes to HiFi equipment:

As far as I understand, getting an external DAC only makes sense if you are able to bypass the internal DAC using a line out jack. In order to do this with both devices I would need two cables plus the external DAC. This is a lot of stuff to carry around (in addition to the external amp I will need to power the cans). The other option would be to use the headphone jack with a standard cable using iPhone's and Nexus' internal processing and amplification. I would then skip purchasing a dedicated DAC and just use an external amp to power my headphones.

My research so far has yielded rather disappointing - as in inconclusive - results. True audiophiles always prefer raw output that is passed on to a DAC & amp combo while others say that both the iPhone and the Nexus already have very capable DAC's and (!) it is acceptable to just use an external amp even if it means amplifyng the already processed and amplified signal once more. To sum it up and pose a question you guys can actually and directly address: Would it make sense to pair both devices with a Fiio E12 using the standard headphone jack as opposed to the Apple connector/micro USB out.

Suggestions for portable headphone amp

Reply #1 –
Quote from: Veydar on
I have a pair of HD 600's connected to the Headphone Out of my Xonar Essence STX, since 90% of my music listening happens at the computer. I would like to be able to use my headphones with my iPhone 4s and my Nexus 7 (2013) when I am at my parents place for example. The HD 600's have an impedance rating of 300 Ohms (up to 550 Ohms depending on the frequency).


Generally one amps lower impedance devices.  Amping a high impedance pair of headphones will make them louder, but do very little else.  Are you already running into the maximum volume those devices can supply?  Be aware, many amps will only go 5 or 6 dB above what an iPhone can put out, so you will have to chose the amp very carefully if you need significantly higher volume.

Quote from: Veydar on
As far as I understand, getting an external DAC only makes sense if you are able to bypass the internal DAC using a line out jack.


No, that is absolutely wrong.  Using the line out jack is for convenience.  It saves you from having to adjust the volume when you switch between headphones and the amp.  There is no other reason to use it, so if you don't care about changing the volume, the headphone jack can also make sense.

Quote from: Veydar on
My research so far has yielded rather disappointing - as in inconclusive - results. True audiophiles always prefer raw output that is passed on to a DAC & amp combo while others say that both the iPhone and the Nexus already have very capable DAC's and (!) it is acceptable to just use an external amp even if it means amplifyng the already processed and amplified signal once more. To sum it up and pose a question you guys can actually and directly address: Would it make sense to pair both devices with a Fiio E12 using the standard headphone jack as opposed to the Apple connector/micro USB out.


I would not bother with a DAC, both of those devices are close to 16 bit limited, so the only real advantage would be on 24 bit material which is probably not important on a portable device.  If you're having volume issues though, an amp might make sense.  If you're happy with the volume, then the amp is at best useless. 

Suggestions for portable headphone amp

Reply #2 –
Thanks for the clarification on the use of Line Out Jacks. It just bypasses the internal amp right?

The volume supplied by both the Nexus and the iPhone is sufficient, I am simply unsure if an amp would improve the sound in any way that someone like me can actually discern. So many people on these audiophile forums only connect their cans to portable players through dac/amp combinations since, according to them, anything else wouldn't "drive" the cans or make it sound "thin". Hard for me to tell apart reality and belief.

Suggestions for portable headphone amp

Reply #3 –
"True audiophiles" are essentially hobbyists with disposable income who will generally go to great lengths to spend their money. They can more accurately be called "true placebophiles" since they appear to accept and believe things not supported by science but rather suggested to them by marketing profiteers. You would be better off forgetting about amps and DACs in your situation.

Suggestions for portable headphone amp

Reply #4 –
Quote from: Veydar on
Thanks for the clarification on the use of Line Out Jacks. It just bypasses the internal amp right?


No it doesn't bypass anything.  On modern DACs there are two amps, a high power one for headphones, and a lower power one for line out.  They both go through the same mixer and volume control, just the line out one has a lower capacity.  You can always use a more powerful amp to drive a smaller load. 

Quote from: Veydar on
The volume supplied by both the Nexus and the iPhone is sufficient, I am simply unsure if an amp would improve the sound in any way that someone like me can actually discern.


Ah, then no, you will have no benefit from an amp. 

Quote from: Veydar on
So many people on these audiophile forums only connect their cans to portable players through dac/amp combinations since, according to them, anything else wouldn't "drive" the cans or make it sound "thin". Hard for me to tell apart reality and belief.


You should probably not pay attention to those people.

Suggestions for portable headphone amp

Reply #5 –
Thank you very much for the replies : ) Saves me money and time! Although this begs the question: What, if any, advantage would I have if I bought an external dac or amp? There's got to be more to it than just more loudness. But from what I've read and based on the answers here, the DACs of modern iPhones are perfectly fine if not better than some of the cheaper external DACs.

e.g. http://www.head-fi.org/t/527355/sennheiser...lly-need-an-amp or http://www.reddit.com/r/headphones/comment...r_hd650_owners/

That's just the kind of reading that confuses the hell out of me. I realize most of these people are probably as experienced in all things audio as I am but I got to base my decisions on something since I can't rely on my own understanding of audio gear.

Suggestions for portable headphone amp

Reply #6 –
Quote from: Veydar on
What, if any, advantage would I have if I bought an external dac or amp?


Louder.

Quote from: Veydar on
I realize most of these people are probably as experienced in all things audio as I am but I got to base my decisions on something since I can't rely on my own understanding of audio gear.


Almost everyone you've linked to has been totally clueless except for that one post where the guy said rockbox is awesome. 

Suggestions for portable headphone amp

Reply #7 –
I know, at least now I do. In the future I will simply ask you  Until someone comes along and say's rockbox sucks and this guy has no idea what he's talking about and I should definitely buy a 1000€ amp ; )

Suggestions for portable headphone amp

Reply #8 –
Quote from: Veydar on
Thanks for the clarification on the use of Line Out Jacks. It just bypasses the internal amp right?

The volume supplied by both the Nexus and the iPhone is sufficient,


That's good!

Quote
I am simply unsure if an amp would improve the sound in any way that someone like me can actually discern.


Is your lack of assuredness because you haven't been given credible answers or is it due to the fact that you are waiting for a voice to thunder out of heaven? ;-)  The credible answers are back a few posts in this thread. The voice from heaven is a little bit harder to arrange. ;-)

Quote
So many people on these audiophile forums only connect their cans to portable players through dac/amp combinations since, according to them, anything else wouldn't "drive" the cans or make it sound "thin".


Sounding thin is very often what audio sounds like when it is not loud enough to suit the listener. Check Wikipedia under "Fletcher Munson" for a more detailed explanation. Bottom line, thin sound is what science predicts when it isn't loud enough.  This is because bass is harder to hear than midrange but bass is even harder to hear at low volumes. Treble is also harder to hear than midrange, but the effect is more uniform as the listening level changes.

I suspect that just about every regular poster to this forum knows this, but this sort of thing is generally not taught in primary or secondary school. I think one has to take an audio related course in trade school or university to be formally taught it. So it is almost a secret from most people including most of the people who post on most of the forums you've referenced.

Quote
Hard for me to tell apart reality and belief.


One learns that when properly instructed about science.  This particular forum is hyper-populated with people who have been formally taught or taught themselves about the science of hearing and other topics in audio. Its terms of service prohibit several broad classes of unscientific posting and they are enforced. Not true of just about every other forum on the web.

Suggestions for portable headphone amp

Reply #9 –
The only thing I would add to the eloquent answers provided by trustworthy objective experts is that if you like to add significant bottom end to your music while using headphones, an amp is absolutely essential. Install rockbox on an ipod classic and try to do ANY bass boosting at all....you just get compression and distortion. Boosting bass frequencies requires significant amounts of power that opamps can't provide. Something like a Fiio E11 or E12 would work. If you only use flat EQ or headphones 32 ohms or less, ignore this post

Suggestions for portable headphone amp

Reply #10 –
I've discovered that much of what passes as today's audiophile truths is often based on rhetorical arguments (i.e.: "Onboard sound is hopeless because there's so much noise from all the nearby components and switching power supplies"), based on obsolete info, or lack of proper level matching. Lots of things can seem to make a "remarkable difference that everyone in the room could hear" until you start level-matching!  I don't have iPhone 4s measurements handy, but the 5 would seem to offer excellent performance:

http://kenrockwell.com/apple/iphone-5/audio-quality.htm

But I think an amp can still make sense if you need higher output than the unaided iPhone can give you.

But if you want to buy a gadget, and are happy to pursue audio perfection far beyond the limit of mere human hearing, who am I to admonish you?    If you wish to try it cheaply, you can get USB digital audio output from your iPhone for $29 with Apple's Camera Connection Kit. For grins, I plugged my iPhone 4 + CCK into the USB input of my Benchmark DAC and it worked great. Won't do that regularly because the iPhone doesn't charge when it's hooked up that way.

Suggestions for portable headphone amp

Reply #11 –
I'll just stick to phone/tablet+headphones now after the very informative answers in this thread. Thanks everyone!

Quote
One learns that when properly instructed about science. This particular forum is hyper-populated with people who have been formally taught or taught themselves about the science of hearing and other topics in audio. Its terms of service prohibit several broad classes of unscientific posting and they are enforced. Not true of just about every other forum on the web.


The problem for me is just that I don't have the time to do that right now. I am a very firm believer in scientific reasoning, to the point where it annoys people, but between regular courses at university and whatever else interests me in the realm of science right now, the study of sound just doesn't fit in anymore ; )

Suggestions for portable headphone amp

Reply #12 –
Go figure, just tried setting the lowpass shelf on my clip+ at 50hz, added a full 24 db boost (the most allowed by rockbox), and with a precut of -15db, I can still get completely respectable volume from 32 ohm circumaural sennheisers. Of course that's from a newish loudly recorded metal album, but you get the point. Unless you're a complete bass head who listens to dubstep at 120 db, or have high impedance headphones, an amp is unnecessary.

Suggestions for portable headphone amp

Reply #13 –
Quote from: Mach-X on
Go figure, just tried setting the lowpass shelf on my clip+ at 50hz, added a full 24 db boost (the most allowed by rockbox), and with a precut of -15db, I can still get completely respectable volume from 32 ohm circumaural sennheisers.


A 24 dB bass boost is a very high value; if you really need to boost it by that much in order to enjoy some bass, then maybe your Sennheiser headphones are inadequate for your tastes. I consider myself a basshead, but with my Denon AH-D2000 headphones (which sport a fairly flat frequency response), I only boost bass by 6 dB.

Anyway, boosting frequency bands on Rockbox is only a matter of how close you are to maximum volume without any boosting, since that's the value by which you can boost frequencies and set the precut in order to avoid distortion. E.g. if you usually set volume to -24 dB in Rockbox, you can boost bass by that amount and set the precut to that value as well, and then a volume of 0 dB (max volume without distortion) should still be usable.

Suggestions for portable headphone amp

Reply #14 –
They are cheaper sennheisers, HD418, about $30, they have substantial roll off at both ends. Also remember I said the low pass shelf, not a standard eq band, so ONLY frequencies 50hz and below are boosted, not a wide band making it more difficult to hear the effect but without muddying things up. I know that I should have set pre cut to the same level as boost, but -15 was distortion free and left some headroom volume wise. But anyway it was an example for the OP, and also why I'm ordering some HD280 pros in a couple days.

Suggestions for portable headphone amp

Reply #15 –
Quote from: saratoga on
Quote from: Veydar on
Thanks for the clarification on the use of Line Out Jacks. It just bypasses the internal amp right?

No it doesn't bypass anything.  On modern DACs there are two amps, a high power one for headphones, and a lower power one for line out.  They both go through the same mixer and volume control, just the line out one has a lower capacity.  You can always use a more powerful amp to drive a smaller load. 

I don't think line out on iOS devices goes through the volume control. In fact I have seen very few if any that do that generally speaking. On very old iPods (I think until 3rd gen or so) the line out audio didn't even go through the EQ IIRC.

I'm talking about the 20-pin connector though, don't have experience with the new connector.

Suggestions for portable headphone amp

Reply #16 –
Quote from: andy o on
I don't think line out on iOS devices goes through the volume control.


No, it does.  Take a look at the audiohw_set_lineout_volume function in the ipod 6g audio driver if you haven't already.

Quote from: andy o on
On very old iPods (I think until 3rd gen or so) the line out audio didn't even go through the EQ IIRC.


EQ is a software function running on the CPU. All audio decoded on a CPU passes through that CPU.  Maybe they disabled the EQ if you plugged in the line out, which would be odd, but possible if they wanted. 

Suggestions for portable headphone amp

Reply #17 –
Ah, you mean that it automatically locks the volume when line out is plugged? I thought you meant that you could control it.

Suggestions for portable headphone amp

Reply #18 –
I can't remember if we let users control it in Rockbox. Apple does not in their software.
 

Suggestions for portable headphone amp

Reply #19 –
Update. Got the 280 pros today. Forget anything I said about amping. At 64 ohms, these things are efficient right down to 20hz without eq or amping. From the headphone jack of my humble lumia 520 every octave of the spectrum is audible and theres no shortage of volume. That is not just subjective hey I got a new toy nonsense. In fact, I was concerned that the difference from my HD418s would be disappointing, that at the price the 280s sell for and all the hype around them I'd feel ripped off (I'm a firm believer in diminishing returns). Not so, these things are monsters. Moral is, if you feel your portable device/PC output isn't powerful enough, just get better headphones. EFFICIENT ones. Slapping some battery powered oomph box on these would be criminal. The junk Monster and Dre sell for more than double the price SHOULD be criminal. Thanks Arnie for recommending these!