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How much difference does a portable amp make? - Page 2

post #16 of 53
Thread Starter 
This is an excellent discussion. I have been looking at the total hothead but I think I'll be holding off for awhile since funding needs to be allocated elsewhere. I think a 160 GB iPod is higher up on the list since my current device can't hold all that I have. Also, what's this JMT fellow I have read about who is known to build portable amps?
post #17 of 53

i think portable amps make a huge difference depending on the IEMs used.

 

case in point: the ER-4S - they're pretty nice when amped properly/have good synergy going etc, yet unamped, it sounds like utter garbage. 

post #18 of 53

I'm not sure which generation of iPod your 80 gig is, but if it's a 5.5g video or earlier, you may actually want to keep it if you're primarily concerned with the sound quality.  Starting with the iPod classic, Apple switched to Cirrus Logic for their internal converters, and the general consensus is that they don't sound as good as the Wolfson converters in the earlier ones.  Yes, it's a bit of a hassle, and you'll have to swap out music every now and again, but just worth considering.

 

As far as amping IEMs goes, while I agree that most DAPs should have no trouble giving the average IEM enough power, its the quality of that power that can be an issue.  Many DAP ICs are relatively high noise, and have poor intermodulation characteristics.  My SE-5s, for example, have what I'd consider to be an unacceptable level of hiss straight out of my brother's iPod Classic (having rockboxed and rebuilt my 5.5g video with the AD4705-2 chip, it's usually not an issue at anything approaching a sane listening level).  However, even his $15 FiiO E1 more or less eliminates it.  I certainly wouldn't, personally, spend big money on a portable amp for IEMs, though I think of my SR-71b as being a fantastic purchase (primarily because it will push my K1000s to a point in balanced output, which lets me mix and master on the road).  That said, I know a number of people who simply don't find IEMs comfortable, and prefer full-size closed shell cans even for travel listening, and a portable amp definitely helps in that case.  I also struggled to push my first IEMs, RE-0s, straight out of an iPod, so it may well depend on the model you have.  I think the overall point here is, there's not necessarily a cut and dry answer to whether or not a portable amp is worth it for you.

post #19 of 53

It depends where you take the feed from. If you feed the amp from a line out, what happens is that the signal to noise ratio is far better so an amp (in effect) turns DOWN the volume coming from the  source and therefore reduces the noise as well.

 

From headphone out, the noise remains constant at any volume (normally), therefore I would then agree with Erik but not from a line out.

 

Then there is also impedance out which could alter the sound as well as the tonal characteristics of the amp itself being planted on top of the earphone's sound.

 

The amp will also provide plenty of power just in case the source (as it often is) is low powered and driving ok, but struggling to provide proper current for low impedance or provide sufficient voltage swings for high impedance.

 

If it's just a case of being able to hear music, then I'd say a portable was not necessary - you'll get sound from a portable to a K701, but if you ensure that you go from line out the improvements you can get are:

 

Improved signal/noise

Better dynamics

Slight tone colour shift

 

Although it's not as convenient for portable which is perhaps more in line with what Erik is getting at.

 

Most people are satisfied with iem's direct, but it depends how critical your ears are.

 

Ian

post #20 of 53
Quote:
Originally Posted by Eric_C View Post




But an Ultra Desktop isn't portable, and doesn't even qualify as a transportable. Shouldn't we be recommending portable amps that illustrate the difference amping can make to OP's proposed setup of HF3 + iPod/iPhone?

 

Also, which IEM has an impedance of 4 Ohms? I thought single-digit impedance was the domain of speakers.

 

quite a lot of multiple driver in ears will present a complex and varying single digit impedance at some frequencies, impedance specifications are usually given at 1khz, at bass frequencies and with real music signals the story can be quite different. current delivery is what these things need, not voltage gain. this pretty simple fact seems to be forever causing people trouble on this forum and the perennial 'if ts able to go loud its as good as it gets' catch-cry is pretty inaccurate and doesnt look at even half the picture

 

plus another gem of an outdated over generalization WRT portables and battery power. Uncle erik obviously isnt aware that due to solar, other renewable energy and automotive investment; single 25 x 65mm lithium polymer cells that are available to anyone, can now put out a constant 70amps and burst up to 140A (at a nominal 3v3 thats a constant 231W with bursts of 462W) with an output impedance of less than 10mOhms for a single cell and VERY low noise, at regular solid state voltages this is overkill and capable of melting anything but high gauge wires, not under powered. good luck getting anywhere near that with AC without serious investment, space etc Thats if you can do it at all, its pretty much the perfect power supply.. the wall and transformer isnt even powering (not even connected to it in fact) the AC powered unit the vast majority of the time, the capacitors are doing the heavy lifting, these batteries are basically very high performance capacitors that have the clean DC already in there.

 

that being said, the etys are about as easy a load as you are going to get for iems, single driver, fairly linear frequency response and impedance curve, pretty efficient. not likely to improve all that much over the pretty respectable iphone HP output with ANY amp. the ER4S were a little more tricky, these not so much.
 

 


Edited by qusp - 8/3/11 at 5:14am
post #21 of 53

The Total Bithead mentioned above is quite portable. My point is that an amp can make a huge difference with IEM's. As to an IEM with impedance of 4 Ohms that is a bit ludicrous. I was merely making a point that there are plenty of good IEM's out there with low impedance ( around 18 Ohms ) and and some amps cannot drive them. The bass will be completely washed out or nonexistent.

 

The Bithead is also a nice portable DAC so you can not only have a portable headphone amp, but a decent digital to analog converter that fits nicely in your pocket. This is especially helpful if you are not satisfied with the audio output coming out of a computer you are working with.

 

I use my Bithead with my iPod all of the time at work and really enjoy the boost it gives my headphones / IEM's.

post #22 of 53

Look into your heart.  Sounds corny, huh? Do you really want a portable amp or do you just want a toy -- something new to learn about and experience? Or are you concerned you won't be squeezing every last tingling shiver from your Etys? Do you really want to lug around another hunk of metal and plastic that has to be recharged?

 

Hey, I've bought crap just 'cause I can or 'cause I was curious, not because I needed it or even wanted it. We've all done it or will do it.

 

With all audio, be it home theater, desktop heaphones, or portables, my advice is to spend most of your cash on whatever actually generates the sound waves, and in this case, the IEM. You acheive the most significant differences with drivers (be they large or tiny). Leave the amps to the golden ears or those banking. Don't get take this the wrong way, but, if your aim is the Etymotic HF3 then you don't fall into either category. Just my 2 $.01.


Edited by KlausGut - 8/3/11 at 9:39pm
post #23 of 53
qusp, obviously you don't know how hot proper class A operation gets.

Even if you had sufficient power, it'd be too hot to hold and well above the 105° C ratings of most components.

Unless you want to carry around a few pounds of heatsink. Suppose you could wear it like a backpack.

Portables are compromised.

Again, you don't need a portable for the vast majority of IEMs. They're a waste.

Again, if you're listening at home, you might as well buy a desktop. They're often cheaper, too.

You're making excuses for an irrelevant piece of hardware. You don't have a financial dog in this fight, do you?
post #24 of 53

eermmm, this is in reference to what exactly? i dont see the relevance, you mentioned transportable kit, said nothing about having to be class A and then said as long as it was AC powered. I simply questioned the need for the AC, because batteries can easily supply enough current and voltage for a transportable headphone system (as long as its SS and you arent trying to run 200v tubes), even class A is doable if it doesnt go in your pocket and sinking to get rid of what 5-10W could easily be designed into a case. 

 

i know very well how hot proper class A gets, being that i'm just winding up (casework stage) a balanced 2 x 60W (woofers) and 2 x 35W (tweeters) (all Class A, about 160-200W total dissipation PC simplified numbers), biamped and digitally crossed speaker rig with a pair of aleph JX (power amps), a pair of power jfet circlotrons (more power amps) and 2 x balanced dacs, one with a CLASS A IV stage that dissipates 50W for a 3Vrms signal. Youde be a bit silly (edit for uncalled for severity) to even try to do discrete Class A portable, especially with how good Class AB sounds these days and given decent opamps mostly operate in class A. Depending on the load it could be done, but i dont know why. a discrete input, or output stage perhaps for a bit of flavor.

 

the heat is there regardless of where the power comes from, in fact more from AC as you have the TX, PSU and bridge creating heat also

 

 

kinda off topic argument with Erik for those interested (Click to show)

 

if properly designed, gear shouldnt get hotter than 65->70 degrees max (with internal die temp a touch higher) and indeed for 2 x 60W + 2 x 35W Class A output i have some pretty serious heatsinks, about 60kg of them, but thats another story. I wouldnt even attempt to run anything but perhaps the jfet input stage on batteries, but for a transportable headphone system, powering any headphone you can think of (apart from electrostats, or maybe some of the planars), modern batteries are perfectly sufficient and have nothing to do with the heat problem. more heat is created in the process of propelling a 1/8th scale jet at a couple hundred km/h than a set of headphones and thats their bread and butter.

 

nope, no dog in this fight, only stuff other than cables ive designed and built of late is for my own enjoyment. I just dont like seeing your over simplification of the issue all around the forum, based on what i consider to be untruths, saying that portable amps or indeed broadening that to battery powered transportable amps, cannot output enough power now to be worthwhile, is just bollocks, they can output 2-3W+ without too much trouble if you were designing for that sort of output.

 

2-3w= 2000-3000mw (way overkill, more than needed for 600ohms) so say <7v swing for the higher impedance headphones (good enough for Borbely, good enough for me) can be provided with a +/-9v power supply and a pair of buffers capable of 250ma that can swing within 1v of the rails into 600R (with much less than 50ma of that needed with the 7v swing =350mWPC for any reasonable headphone load, but much more on tap for lower z headphones) and that can be dealt with with nothing more than a large copper ground plane on the pcb. add a small fan and a cpu heatsink and the sky is the limit, although the lme49610 buffer i'm talking about, will actually start to struggle at ~700mW each, so you would have to parallel 2 of them to get the 2-3w, but i'm not building for that much power, my needs are much more modest.

 

for example with 'the Wire' a diy headphone amp project that uses these buffers, I tested how low i could take the voltage with hd600 before it started to sound lacking and i got down to +/-5v. I run it at +/-12v normally just because i can and the distortion numbers are better. 

 

 

 

just as a point of interest too, there are a number of people running small aleph minis and F5s on batteries powering efficient speakers with pure class A

 

 

sorry for the massive post guys, i just came back and added to this one rather than making another one and put it inside the spoiler box for those that would rather skip it.

 

 


Edited by qusp - 8/4/11 at 9:41am
post #25 of 53
Quote:
Originally Posted by Merck View Post I notice amps and the associated accessories can get quite expensive so I was just wondering what the real advantages of using a portable amp are in regards to IEMs.


The only definite things with portable amps are the numbers your wallet will be missing and the weight your pocket will be holding.

post #26 of 53
Thread Starter 
Quote:
Originally Posted by KlausGut View Post

Look into your heart.  Sounds corny, huh? Do you really want a portable amp or do you just want a toy -- something new to learn about and experience? Or are you concerned you won't be squeezing every last tingling shiver from your Etys? Do you really want to lug around another hunk of metal and plastic that has to be recharged?

 

Hey, I've bought crap just 'cause I can or 'cause I was curious, not because I needed it or even wanted it. We've all done it or will do it.

 

With all audio, be it home theater, desktop heaphones, or portables, my advice is to spend most of your cash on whatever actually generates the sound waves, and in this case, the IEM. You acheive the most significant differences with drivers (be they large or tiny). Leave the amps to the golden ears or those banking. Don't get take this the wrong way, but, if your aim is the Etymotic HF3 then you don't fall into either category. Just my 2 $.01.

I do appreciate your thoughts on this as I have seen that they are quite accurate. I have decided to hold off on an amp for the time being. I realize the more important thing is finding a suitable portable audio device with enough capacity for my music library since the current 80 gig iPod I have is not sufficient. I have been learning a lot in this thread and others about amps and how they relate to headphones of various types. Lots of info, one of the many reasons I love online forums.
post #27 of 53

yep, I agree, as i said in my first post at the end of it, if its just the ety, forget the amp, get a good source tyhat best suits your needs and i dont mean audiophile type player, but if you want to upgrade from here, upgrade the headphones, great headphones will sound better out of a crappy source and no amp than average headphones out of the best amp

post #28 of 53

Quote:
Originally Posted by Uncle Erik View Post

Personally, I don't see the point of portables.
Highly efficient IEMs and headphones run fine right out of an iPod or similar. No need to buy a portable.
 

 

Exactly.

 

To OP, I'd much rather have you spend your time and money on acquiring better source material and have that ripped in lossless format for your iPod. 

Nowadays I just stick an earbud or ksc into whatever source I'm carrying. No amps, no fat wires, no unwanted attention, no hassle.

 

Update:

Quote:
Originally Posted by Merck View Post

I am new to high end audio ... I have never heard the difference between an amped headphone and just one that is plugged in to the music device. 

 

Completely missed this detail.

Please make an effort to audition some equipment before you start buying them.


 


Edited by Akabeth - 8/4/11 at 11:12am
post #29 of 53

btw if thats a 5.5G ipod then youll wont to keep a hold of it.  get a line out dock to it and then try an amp.  then say hello to the treble detail that was supposed to be there.

 

you know there are gateway drugs, things like the FiiO E5 to give you a taste of what an amp can do.

post #30 of 53

 

Quote:
Originally Posted by mark2410 View Post

btw if thats a 5.5G ipod then youll wont to keep a hold of it.  get a line out dock to it and then try an amp.  then say hello to the treble detail that was supposed to be there.

 

you know there are gateway drugs, things like the Minibox-ES to give you a taste of what an amp can do.


fixed your typo  tongue.gif

 

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