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OI, SQ and DAPS

post #1 of 8
7/5/12 at 3:02pm
Thread Starter 

According to Apple, the latest generation Classic, Touch and iPhone 4/4s all have 32 ohms.

 

Is 32 ohms considered a high output impedance? Or is ohms and OI two different measurements?

 

Is it true that iPods have high OI and poor transparency compared to a Clip+ and J3?

 

Thank you,

 

Olear

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post #2 of 8
7/5/12 at 4:33pm
32 ohms is typical for a portable device that runs on batteries. It would work fine with most normal headphones. The sound quality is only an issue with mismatched impedences. If you want to use larger cans, using the lineout with a small headphone preamp, like a cmoy, would do the trick. It all depends on the headphones you use.

Line out is perfect. When you patch into a stereo, always use that.
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post #3 of 8
7/5/12 at 4:52pm
Quote:
Originally Posted by olear View Post

According to Apple, the latest generation Classic, Touch and iPhone 4/4s all have 32 ohms.

 

Is 32 ohms considered a high output impedance? Or is ohms and OI two different measurements?

 

Is it true that iPods have high OI and poor transparency compared to a Clip+ and J3?

 

Thank you,

 

Olear

 

Impedance is a measurement, ohm is the standard unit used for measuring. 32ohm is a huge output impedance. The ideal output impedance should be 1/8 of the headphone's impedance, so with 32ohm you'd have to used something like the Beyerdynamic DT880 @ 250ohm - not ideal for portable use...

http://en.goldenears.net/index.php?mid=GR_Mobile&document_srl=9139

It's not 32ohms, as you can see there. It's still a bit high, but nothing obscene. The Apple earbuds have 32ohm impedance, maybe that's what you meant.

If you google "headphone amplifier output impedance" check the second link, it's a very good source of information.

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post #4 of 8
7/5/12 at 5:30pm
They mean "suitable for headphones with impedance of 32 ohms or higher", not that the players' output impedance is 32 ohms. Many new iems have an impedance lower than 32 ohms and a very high sensitivity, so these disclaimers are the dap makers' way of saying that such headphones will be underdamped and have a high noise floor. This goes with the territory with most portables and apple products aren't the worst offenders.
Edited by anetode - 7/5/12 at 5:32pm
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post #5 of 8
7/5/12 at 5:35pm
No, the spec is referring to the apple earbuds which are typical of portable headphones. It isn't referring to the ipod itself. That is capable of pushing many home cans. The easiest way to tell is to take your preferred headphones into an apple store and see if they get loud enough. Odds are, it will be.
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post #6 of 8
7/5/12 at 5:55pm
Thread Starter 
Quote:
Originally Posted by bigshot View Post

No, the spec is referring to the apple earbuds which are typical of portable headphones. It isn't referring to the ipod itself. That is capable of pushing many home cans. The easiest way to tell is to take your preferred headphones into an apple store and see if they get loud enough. Odds are, it will be.

When I called the 1 800 number for Apple, not a store, I specifically asked what the OI is for the Classic, ipod and iphone 4/4s. 

 

It never occured to me that the answer was for the earbuds.

 

I wonder if I called back and emphasized my question is for the ipod, if they would know.

 

Does the ipod have a higher OI compared with a Clip+ and Cowon J3?

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post #7 of 8
7/5/12 at 6:53pm
That isn't part of the published specs. Try the touch with the headphones you intend to use with it and see if it works. But I would bet that they're all pretty similar. I use my Sennheiser 590s (120 ohms) with my iPhone with no problem.
Edited by bigshot - 7/5/12 at 7:32pm
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post #8 of 8
7/7/12 at 9:14am
Thread Starter 

I understand the Clip has OI of 1, ipod Touch 7, and what is the OI of the J3?

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