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Battle of Battery Operated Portable Headphone Amps

solderdude

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I think you might want to adjust how you look at and test small or portable headphone amps/dacs. You are using big / inefficient phones that you actually would not be using on the go. Maybe iems or other small efficient phones would be more practical.

With small efficient headphones I don't think an extra amp is needed. It is only needed when you want to listen to inefficient headphones while using the phone or small DAP that cannot drive it properly ?
 

Johnb

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I do think you can run just about any cans on 70mW. And very well. For HD650, that is around 120dB Spl. How loud could you possibly want to go? You will have to look far and wide to find any portable amp that puts out actual undistorted 70mW, especially for less than around $300. For the money, 70mW is a reasonable tradeoff.

That said, have to agree, desktop always preferable. IF YOU ARE SEDENTARY. I mean what's wrong with excess power? Fills you with confidence. Like mutually ensured destruction, or 500 HP pickup trucks, or more megapixels. Nice to know its there, if you ever need it.

I move with my laptop from room to room. I hate power cords. So there is your usage scenario for portable amps.

I have a philosophical problem with plugging an iem into a dedicated amp. I know there are very good iem's. I know most would benefit from good, clean, abundant power. But then there's the principal of the matter. A man has to have his principals.

As to how much power a headphone needs, you can safely disregard Amir. He likes to see his eardrums flapping in the wind - makes him feel patriotic, I think.
 

rebbiputzmaker

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With small efficient headphones I don't think an extra amp is needed. It is only needed when you want to listen to inefficient headphones while using the phone or small DAP that cannot drive it properly ?
People use amps for better sound not just power as most do not walk, jog etc with full size phones.
 
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amirm

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So I re-tested the two after letting them both charge. Now when matching levels, the two sound the same. It is just that the O2 has another 20 to 30% turn of the volume left when the NX3s is at max. When turned to that region, it obviously sounds louder and is much more impactful. There, it crosses the threshold I like to see where there is plenty of loudness to work with.

This is a constant conclusion by the way: lack of power is always audible.

Maybe others who don't need to play as loud would find the Topping NX3s good and as such, save money and have a much smaller unit to lug around than the O2.
 
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amirm

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I do think you can run just about any cans on 70mW. And very well. For HD650, that is around 120dB Spl.
My testing is proof that those sensitivity numbers/computations just don't work accurately. There is also the issue of running out of gain if the source material is not recorded to max levels.
 

ishmeister

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My testing is proof that those sensitivity numbers/computations just don't work accurately. There is also the issue of running out of gain if the source material is not recorded to max levels.
I think the HD650 goes up to around 450 ohms at 100hz - HD600 is even worse, 550 ohms at 100hz.
 
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amirm

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I think the HD650 goes up to around 450 ohms at 100hz - HD600 is even worse, 550 ohms at 100hz.
That would certainly explain the discrepancy.
 

Johnb

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Amir, I do so agree about adequate volume. Of course that varies by person. First I owned the hd595's which were ALMOST loud enough on my laptop output. Then I bought the HD650's and the SMSL Idea. Sound great, again ALMOST loud enough. It's maddening, I feel I am being deprived of something. Then I listen to something recorded at lower level. Now inadequate. You just don't feel happy until you've landed in your sweet spot. And you just can't appreciate how good your headphones are because you're irritated every time you reach for the volume control, and find out there is no MORE. No 11 on this guitar amp!

Hope you don't get offended when I tease you about your high listening levels.
 
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amirm

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Hope you don't get offended when I tease you about your high listening levels.
Not at all. I actually don't listen at those levels. I *test* at those levels to make sure when I say something is powerful enough, it encompasses everyone, including myself when I was decades younger. :)
 

JJB70

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People use amps for better sound not just power as most do not walk, jog etc with full size phones.
With small efficient headphones I don't think an extra amp is needed. It is only needed when you want to listen to inefficient headphones while using the phone or small DAP that cannot drive it properly ?

I agree with Solderdude. If you have efficient headphones (and most modern and even not so modern ones seem to be reasonably efficient) and you don't need to push volumes up to earthquake levels then you probably don't need a separate headphone amp. I find my Oppo PM-2's and Beyerdynamic T5P II's can be driven to sufficient volume by my Sony smartphone, and can be made louder than I feel comfortable with by my Shanliing M3s DAP. Both the smartphone and DAP are basically transparent and offer a headphone output that does full justice to properly good headphones. I use the phrase "hi-fi has been democratised", it is probably a dumb cliché but it is also true that genuinely good sound has never been more accessible and that with good files even a typical smartphone or low end DAP provide a genuine hi-fi experience if used with decent headphones. And decent headphones don't have to be expensive, I paid about £140 for a pair of Audio Technica ATH-MSR7's which are superb (if slightly bright).
 

Veri

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Amir, I do so agree about adequate volume. Of course that varies by person. First I owned the hd595's which were ALMOST loud enough on my laptop output. Then I bought the HD650's and the SMSL Idea. Sound great, again ALMOST loud enough. It's maddening, I feel I am being deprived of something. Then I listen to something recorded at lower level. Now inadequate. You just don't feel happy until you've landed in your sweet spot. And you just can't appreciate how good your headphones are because you're irritated every time you reach for the volume control, and find out there is no MORE. No 11 on this guitar amp!

Hope you don't get offended when I tease you about your high listening levels.
Buy the THX AAA and you'll have power for years :) all the power you yearn for and more lol
 

Johnb

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When is an amplifier loud enough? When is gets as loud as you every want, plus a quarter turn of the dial. If you can't blow past your sweet spot, say "Nah, too loud" and dial back, then how will you ever know? How can you ever be happy?
 

solderdude

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When is an amplifier loud enough? When is gets as loud as you every want, plus a quarter turn of the dial. If you can't blow past your sweet spot, say "Nah, too loud" and dial back, then how will you ever know? How can you ever be happy?

When it plays loud enough (yet not distorted) on all of your headphones you have the right amp an can be happy.
Problem is a 12 Ohm headphone is not the same as a 300 Ohm headphone.
Amplifiers don't supply power, they supply an output voltage.
Amplifiers have voltage AND current limits.

Sure... both may play equally loud on the same power (mW) but to reach the 70mW, you quoted earlier, the 12 Ohm headphone needs just 0.9V but the 300 Ohm headphone requires 4.5V.
A difference of 14dB in 'loudness' when both headphones are equally efficient in power rating and is operated on the exact same volume control position.
The 300 Ohm headphone draws just 15mA but the 12 Ohm version 75mA.

In this case one would know and could be happy if the amp can supply at least 6V (4.5V + 3dB headroom) and 100mA but not necessarily both at once.
 

Maki

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Personally I found the NX3S more than loud enough for hard to drive headphones, even with a -10dB preamp for EQ. The bass boost switch is actually useful too - it's not a mud button like in some Fiio portables.
 

mikehoopes

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I have to chime in with a shout-out to my current favorite portable amp, actually a wired/wireless DAC/amp: the Radsone EarStudio ES100.

Even if you have ample power/resolution from your 3.5 mm source output, EQ options run surprisingly thin. We’re not talking the power levels of the review units in this thread, but you can clip this on your shirt and go. I regularly hook it up to my HD 650s, when I’m at home. Feels like winning. I can also compensate for China-market-oriented tunings of FiiO IEMs.

Listening to the Live From Here broadcast right now on my iPad>>ES100>>FiiO FA7 on AAC Bluetooth. Not bad.
 

rebbiputzmaker

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I agree with Solderdude. If you have efficient headphones (and most modern and even not so modern ones seem to be reasonably efficient) and you don't need to push volumes up to earthquake levels then you probably don't need a separate headphone amp. I find my Oppo PM-2's and Beyerdynamic T5P II's can be driven to sufficient volume by my Sony smartphone, and can be made louder than I feel comfortable with by my Shanliing M3s DAP. Both the smartphone and DAP are basically transparent and offer a headphone output that does full justice to properly good headphones. I use the phrase "hi-fi has been democratised", it is probably a dumb cliché but it is also true that genuinely good sound has never been more accessible and that with good files even a typical smartphone or low end DAP provide a genuine hi-fi experience if used with decent headphones. And decent headphones don't have to be expensive, I paid about £140 for a pair of Audio Technica ATH-MSR7's which are superb (if slightly bright).
You are missing my point, so no need to continue.
 
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amirm

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You are missing my point, so no need to continue.
Your point lacked merit. If you are a heavy headphone listener/use various products, you would realize what I and others are saying.
 

rebbiputzmaker

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Your point lacked merit. If you are a heavy headphone listener/use various products, you would realize what I and others are saying.
Of course you would say that, but clearly people travel with smaller devices as you pointed out regarding the O2, may also use iems or travel friendly phones.

NP if you feel that power and massive volume is the only thing that matters in an amp. Feel free to overlook anyone interested in sound quality. Sorry for trying to help with info that many users may also find useful.
I also find if amusing that you know and can classify my use of headphones, since I never mentioned it, nor have you asked.
 
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amirm

amirm

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Of course you would say that, but clearly people travel with smaller devices as you pointed out regarding the O2, may also use iems or travel friendly phones.
You are repeating what I said in the review yet imply it is an opposing view???

NP if you feel that power and massive volume is the only thing that matters in an amp. Feel free to overlook anyone interested in sound quality. Sorry for trying to help with info that many users may also find useful.
I also find if amusing that you know and can classify my use of headphones, since I never mentioned it, nor have you asked.
You are back to your combative, non-constructive posts. Think of that before posting again.
 
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