[xnor]

Meremoth, before you can ask that you have to establish that there are two such amps where people hear differences in blind tests. Please let us know asap and good luck.

 

[Meremoth]

Quote:

Meremoth, before you can ask that you have to establish that there are two such amps where people hear differences in blind tests. Please let us know asap and good luck.

 
Please just go away.  Thanks.
 
Now for that mute...

 

[xnor]

Quote:

 
Please just go away.  Thanks.
 
Now for that mute...

So you can't. That's okay.
 
What's not okay is asking why 2+2 can equal 4 but also 5, when you haven't shown the latter.

 

[Meremoth]

Quote:

So you can't. That's okay.
 
What's not okay is asking why 2+2 can equal 4 but also 5, when you haven't shown the latter.

 
What's also not okay is you obsessively following me to different threads trying to make some random/arbitrary point that I'm not even sure what it is, nor do I care in the slightest.  The fact you think I do care is fairly egotistical, and the fact you won't leave me alone is just creepy and weird.

 

[jaddie]

Quote:

Meremoth, before you can ask that you have to establish that there are two such amps where people hear differences in blind tests. Please let us know asap and good luck.

xnor does have a good point, and here's why.  Much can be done with the design and construction of an amp to suggest that it sounds more aggressive, mellow, etc.  It can get down to the finish of the cabinet, choice of knob, physical size and shape, weight, and other factors.  While there's no published research that ties any of these qualities to a specific sonic impression, if you remove all sensory input except the resulting audio, even remove the knowledge of exactly what amplifiers are involved, then test them by auditioning (that's what an ABX test does), the ability of a listener to distinguish between amplifiers diminishes to that equal to a random guess much of the time.  There are exceptions, but if we stick to your rules of identical power, source impedance, and I'll add frequency response too, because it can be deliberately altered, they become indistinguishable in anything but a fully sighted test.

 

[xnor]

Quote:

What's also not okay is you obsessively following me to different threads trying to make some random/arbitrary point that I not even sure what it is, nor do I care in the slightest.  The fact you think I do care is fairly egotistical, and the fact you won't leave me alone is just creepy and weird.

Me commenting on new posts in Sound Science is what I do, I'm not following anyone. If you think I do look up paranoia.
 
This forum is free for anyone, so don't ask others to go away if they make an argument you can't counter.
 
 
 
Back to the two amps that sound different. We could always just do a null difference test. Such tests have been done in the past, and when the amps nulled sufficiently deep, people (such as the guys from Stereophile) failed distinguishing them in blind tests. But looking at a comprehensive set of measurements and comparing them is pretty much equal to that.
Given an input signal you could even calculate how deep the amps would null based on FR, THD, IMD .. measurements.

 

[Meremoth]

Quote:

xnor does have a good point, and here's why.  Much can be done with the design and construction of an amp to suggest that it sounds more aggressive, mellow, etc.  It can get down to the finish of the cabinet, choice of knob, physical size and shape, weight, and other factors.  While there's no published research that ties any of these qualities to a specific sonic impression, if you remove all sensory input except the resulting audio, even remove the knowledge of exactly what amplifiers are involved, then test them by auditioning (that's what an ABX test does), the ability of a listener to distinguish between amplifiers diminishes to that equal to a random guess much of the time.  There are exceptions, but if we stick to your rules of identical power, source impedance, and I'll add frequency response too, because it can be deliberately altered, they become indistinguishable in anything but a fully sighted test.

 
Ahhhh, very interesting.  

So if someone had the intent of building an amp with a specific sonic impression, there's no guide or published research or data suggesting how to go about doing that?
 
Thanks for the info.  

 

[bigshot]

Why would anyone want an amp that alters the sound? That's what signal processing and EQ are for. You want to control the amount of coloration or lack of coloration, not have it hard wired in.
 
If amps sounded different, every time you got a new set of headphones, you'd have to find the amp that matches it. What would work for one wouldn't work at all for another. Total chaos.

 

[mikeaj]

Quote:

Why would anyone want an amp that alters the sound? That's what signal processing and EQ are for. You want to control the amount of coloration or lack of coloration, not have it hard wired in.
 
If amps sounded different, every time you got a new set of headphones, you'd have to find the amp that matches it. What would work for one wouldn't work at all for another. Total chaos.

 
Well, that's what people do anyway each time they get a new amp or headphones. With that exact reasoning.

 

[miceblue]

And this is why having that new FiiO HS2 would be convenient to easily switch between 2+ amps or headphones or sources.

I sometimes have to wonder what companies' intentions are when they have 3 or more different headphone amplifiers other than for the money.

 

[bigshot]

Quote:

 
Well, that's what people do anyway each time they get a new amp or headphones. With that exact reasoning.

 
Man! If I had to do that with my speakers, I'd be starting over again every 8 years or so. That would be a chore.
 
I allow the transducer to be the variable because I don't have any choice. Everything else better be performing to spec, or it goes back for a refund.

 

[mikeaj]

Quote:

Man! If I had to do that with my speakers, I'd be starting over again every 8 years or so. That would be a chore.
 
I allow the transducer to be the variable because I don't have any choice. Everything else better be performing to spec, or it goes back for a refund.

 
Nah, it would be a magical unicorn adventure of life-fulfilling proportions with bundles of new surprises every day! It's the journey that counts, not the destination, right?
 
At least, that's the way some people talk about it.
 
 
Okay, snark aside, I can totally see why some people would do it that way and would be interested in doing so. Nothing really wrong with that if that's what you want to do, and you have the money. But it's not for me. I don't want to collect intentionally-underperforming amps and source components.

 

[Brooko]

Hello lads
 
Hope you don't mind me posting this - but it does have particular relevance to the title of this thread, and I need some help.
 
The issue - my dear old ma turns 70 this year - loves her music (huge classical fan), but very rarely listens to it - as it means she's tied to their older receiver set-up, and speakers aren't always ideal as Dad doesn't have quite the same classical love she has.  A little bit more about Mum - she does wear modern hearing aids - so her hearing is definitely not perfect - not even close.
 
Last time I visited - I took my headphones and my NFB-12 - to see what she liked.  We used her music, and she spent a good couple of hours comparing the HD600, K701 and my DT880.  She told me she liked the K701's best - both comfort and sound (I modified the headband a while ago - so they are very comfortable now).
 
So - I'm giving her my K701s - and I want to get a reasonably priced portable set-up that will be able to drive them.  I don't want to spend a fortune - and initial thoughts are either an iPod Touch + amp, or maybe something like the new Fiio X3 (which is based on the E17 amp).  Using something like a Clip + amp is not really an option as the screen is going to be to small / it'll be too hard for her to handle.
 
My question - what portable amps will be able to power the K701 to a reasonable level (and yes I know it's not all about volume)?  It doesn't have to be perfect in this particular case.  Alternatively - would the power from an E17 be enough to drive them - K701 require high current right?  If it is - then the Fiio X3 by itself should work.
 
The K701 are 62 ohm with a sensitivity of 105 dB SPL/V
 
The E17 delivers  > 540 mW@16Ω, 270 mW@32Ω, 30 mW@300Ω
Gain is 0dB and 6dB.
Output impedance is <0.3 ohm.
 
Do I need to look for something more powerful - or should this do the job?
 
Any help appreciated.  I get a little confused with the science - and I'd rather get proper oil on what I need rather than 30 suggestions from well meaning people who don't really have a clue as to the actual requirements 

.

 

[mikeaj]

I checked FiiO's website, and that says only 220 mW into 32 ohms for the E17.
 
Even at that level, it's around 2.65 V rms into 32 ohms, so it should at least be that much for ~62 ohms and not really have performance issues for those. So more than 115 mW or so max. Depends.
 
Wait, I should have just checked the X3 page. 540 mW into 16 ohms, so 3 V no problem. So say 145 mW into 62 ohms, very similar to ~115 mW though anyway. If it can handle 16 ohms like that, it has plenty of current and probably won't mind 62 ohms.
 
On the other hand, InnerFidelity measurements show lower sensitivity than AKG's specs, more like 100 dB SPL / 1 V (88 dB SPL / 1 mW). Crazily enough, that means that 145 mW is not quite enough for 110 dB SPL peaks, which I think are realistic if you want to listen at a high volume to certain classical recordings with very low average volume. It may realistically be enough. Depends on tastes.
 
Or actually, their second sample, was slightly more sensitive and would be driven to just over 110 dB SPL when maxed out there. So let's just say that it's in that range.

 

[Brooko]

Thanks Mike
 
It doesn't need to be perfect for her.  She's all about the music - especially when you see her with eyes closed, K701 on, totally swept away.  If the X3 will get her close to that without major distortion or clipping, it should be the ideal solution for her
 
Really appreciate the help