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Why am I hearing a difference in amps? - Page 2

post #16 of 25

Driving the iPod to 95% could plausibly be causing an audible amount of distortion.

 

Given that the HE-500 is a relatively low impedance headphone, we're pushing heavy on the current. It's possible that the headphone amp inside of the iPod is struggling to put out the current required for 95% volume and is introducing distortion. This added distortion would reduce the imaging on the HE-500 and reduce potential soundstage wideness or detailing.


One test that I would try is to use the iPod at a lower volume and do your best to level match with your amp, then compare to see if you can tell a difference with the sound.

post #17 of 25

If amp a was set up to impedance x and amp b set up to be flat at impedance y,

why is it so hard to imagine the results with a particular headphone would be different?

A transmission with a set of gear ratios takes advantage of an engine's power band.

Tie it to a slightly different engine with a different power curve, and things don't work so well.

Is the transmission a bad design? The engine? No, just not good together.

Each was designed a certain way at a certain price target. It's not broken.

I still take exception to "all properly designed amps should sound the same."

It's a statement with no merit.All transistors and chips have different operating parameters.

And of course this dictates how they are deployed in amps. And available devices change all the time, requiring

on the fly changes. So regardless of design goals, there are thing s the engineer has no control over

that creep into the process. Flat response? Under what test? Change the test slightly and results may not

test the same.

post #18 of 25
post #19 of 25
Thread Starter 

OK, I'll try to make things a bit clearer.

 

iPod amp = headphone out on top of iPod

E11 = Fiio E11 being sourced by the iPod using the iPod's line out at the bottom (unless otherwise noted)

O2 = Objective 2 amp created by nwavguy as a simple and inexpensive amp designed to be completely transparent to the ear.

 

All tests were done with HE-500 and Vsonic Gr06 24ohm iems

 

While using the iPod's LOD, both the E11 and O2 sound identical, I cannot distinguish any difference in sound at regular listening level.

The difference comes when I go out of the iPod's internal amp. Regardless of whether I plug it into an external amp (E11 or O2) or plug the headphones direct into the iPod.

 

I just don't understand what is scientifically going on in the iPod's amp (headphone out) that causes the sound stage to collapse.

post #20 of 25
Thread Starter 
Quote:
Originally Posted by bigshot View Post
 

Do all amps sound the same?

http://webpages.charter.net/fryguy/Amp_Sound.pdf


Thanks for bringing this in. I thought this was common knowledge in the sound science forum, but didn't have the link readily available.

post #21 of 25

the main reason for hearing differences is to "just listen" for them - without level matching, controls, Blinding protocol...

 

http://www.head-fi.org/t/469428/tube-and-ss-amps#post_6358419


Edited by jcx - 11/1/13 at 9:09pm
post #22 of 25
Quote:
Originally Posted by mnarwold View Post
I just don't understand what is scientifically going on in the iPod's amp (headphone out) that causes the sound stage to collapse.

 

Well, you did not provide enough information for finding it out what the problem might be. So, for now, the most obvious explanation is at least one of unmatched levels, expectation bias, or incorrect usage (clipping, EQ, etc.).

 

At least you could try testing the iPod with a headphone load, and record its output, and that of the E11, with a splitter and a suitable sound card. Set the volume on the iPod and E11 to whatever levels you think they are matched at for reasonable loudness, and then run the tests without changing the volume on any of the devices. You could use RMAA, or record this sample, and post the resulting files. With RMAA, you can generate a WAV file that can be copied to the iPod. The recording format should preferably be 96 kHz/24 bits, but 44.1/16 is enough for detecting any serious problems; note that recording on Windows can be tricky if you want to avoid sample rate conversion by the system. Also make sure that the recording level is set correctly and there is no clipping (onboard codecs can handle up to about 1.4 Vrms, if that is what you would use); it should be the same setting for both devices to allow for detecting any level matching issues.


Edited by stv014 - 11/2/13 at 3:15am
post #23 of 25

Do you know anyone with the same model iPod?

 

It might be something to do with the volume control or the socket on your model.

post #24 of 25

This old thread has some pertinent info. See post #2.

 

http://www.head-fi.org/t/627111/what-is-the-sound-quality-of-iphone-ipad-ipod-touch/15

post #25 of 25
Thread Starter 
Quote:
Originally Posted by RonaldDumsfeld View Post
 

This old thread has some pertinent info. See post #2.

 

http://www.head-fi.org/t/627111/what-is-the-sound-quality-of-iphone-ipad-ipod-touch/15

This is exactly the type of information I was looking for. Thanks! You win.

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