[estreeter]

Relax - it was just a suggestion for future reference, This whole debacle will undoubtedly rear its ugly head with the arrival of the ODA/ODAC - whatever their technical merits may or may not prove to be, I'd suggest that a little more tact might be in order in future. Personally, I think its all good grist for the mill, but its not hard to see why some have chosen to greet the 02 with hostility. 

 

[chrislangley4253]

Quote:

Relax - it was just a suggestion for future reference, This whole debacle will undoubtedly rear its ugly head with the arrival of the ODA/ODAC - whatever their technical merits may or may not prove to be, I'd suggest that a little more tact might be in order in future. Personally, I think its all good grist for the mill, but its not hard to see why some have chosen to greet the 02 with hostility. 

I simply won't ask any questions any more.. My days at head fi are definitely limited. And yeah, I understand why people get hostile.

 

[mikeaj]

As suggested in the other thread:
 

I would like this thread [O2 vs TOTL] to stay alive and any talk of blind testing or it's creator stay here, and Mav's thread stay in the amp section.

 
I've been guilty in the past myself, but maybe we should dump the general discussion about attitudes and particularly anything remotely contentious or relating to experiments and testing in there:
http://www.head-fi.org/t/603728/o2-vs-totl
 
and leave the amp reviews, amp discussion (where to get parts / wall adapters, gain settings, whatever) here.

 

[proton007]

For those using the O2 with their portable media players, how much volume do you use on the source? Do you feel the need of using the gain switch ? 
In my case, the volume from my iPod is the same as I would have for earphones. But then I do have to use the gain.

 

[estreeter]

I use the dedicated line-out from my T51 - its got plenty of juice. 

 

[keanex]

Quote:

For those using the O2 with their portable media players, how much volume do you use on the source? Do you feel the need of using the gain switch ? 
In my case, the volume from my iPod is the same as I would have for earphones. But then I do have to use the gain.

You should be using a line-out from your iPod so the volume on it would be negligible. 

 

[proton007]

 
Quote:

You should be using a line-out from your iPod so the volume on it would be negligible. 

Thanks for the tip!

 

[chrislangley4253]

Nwavguy is gonna do line out vs headphone out soon.. if you are using headphone out, I suggest keeping it under 60%

 

[keanex]

Using a headphone out to connect an amp to your portable situation kind of defeats the purpose since you're still going to have the less than stellar amp from your PMP in the mix.

 

[chrislangley4253]

Quote:

Using a headphone out to connect an amp to your portable situation kind of defeats the purpose since you're still going to have the less than stellar amp from your PMP in the mix.

It's debateable whether or not it makes much of a difference.
 

 

[maverickronin]

Quote:

Using a headphone out to connect an amp to your portable situation kind of defeats the purpose since you're still going to have the less than stellar amp from your PMP in the mix.

High impedance load = less distortion.  The O2's 10 Kohm input impedance is a lot easier to drive than any headphone you're ever likely to plug into a DAP.

 

[chrislangley4253]

did you mean to say low impedance there maverick?

 

[stv014]

Quote:

did you mean to say low impedance there maverick?

No, a high impedance load is easier to drive at the same output voltage, and results in less distortion. This can be verified on the THD vs. voltage vs. load impedance graphs for various devices.
 

 

[mikeaj]

Quote:

Using a headphone out to connect an amp to your portable situation kind of defeats the purpose since you're still going to have the less than stellar amp from your PMP in the mix.

This was already addressed above, but see here regardless, if you want an example:
 
http://www.head-fi.org/t/568705/review-nwavguys-o2-diy-amplifier/1080#post_8150435
 
More or less, the usual objection with running through the headphone jack is double amping—running through the headphone amplifier of the original device and then to another headphone amplifier.  In the above, the double amping results are better for reasons described above.  There's no real line output on that sound card (that's not through a headphone amplifier), so it's a fair comparison and more or less the same scenario we're talking about, with a portable media player.
 
Anyway, the point is:  sometimes headphone amplifiers help.  Often times, double amping is not a huge deal.  If you feel like you can benefit from an amplifier, go ahead, even if you don't have a magic line out dock.

 

[proton007]

 
Quote:

This was already addressed above, but see here regardless, if you want an example:
 
http://www.head-fi.org/t/568705/review-nwavguys-o2-diy-amplifier/1080#post_8150435
 
More or less, the usual objection with running through the headphone jack is double amping—running through the headphone amplifier of the original device and then to another headphone amplifier.  In the above, the double amping results are better for reasons described above.  There's no real line output on that sound card (that's not through a headphone amplifier), so it's a fair comparison and more or less the same scenario we're talking about, with a portable media player.
 
Anyway, the point is:  sometimes headphone amplifiers help.  Often times, double amping is not a huge deal.  If you feel like you can benefit from an amplifier, go ahead, even if you don't have a magic line out dock.

I thought the issue with higher impedance becomes the current requirement. If the internal impedance of the source amp is taken into consideration, more current is needed to get the load to the same potential than without the internal impedance, *unless* the load is significantly higher than the internal resistance. 
Going with this logic, I think its possible to use the phone out as the input to the amp (if the amp's total resistance as seen from input side is in thousands of Ohms), but its better to remove the internal resistance for best electrical efficiency. From the signal point of view, things may be different.