[jseaber]

This may be answered earlier, but this is by design. The O2's power management circuitry shuts off the opamps (no sound) when batteries are low, but the LED is tied directly to the batteries/power switch (it stays lit). If you get no sound from the O2, it's time to charge!
 
Quote:

I had one of the ones I built to give out for Xmas gifts not work on a set of battery's...   I took the battery's out and put them in a dedicated charger in an attempt to figure out
which one was bad..   both of them charged up fine, I put them back in the amp and the amp has worked perfectly ever since...   not sure why..
 
 

 


 

 

 

[Crazy*Carl]

I  am trying to figure out if the O2 is going to benefit me and could us some help. I have heard other amps such as the audio gd sparrow with a very powerful 10v output and I was never able to tell a difference or pass a blind test with it against my computers onboard sound. Because of this I am doubtful I am goIng to hear any difference with the O2. Is there any reason the o2 will do something for me these other amps did not? Thanks.

 

[maverickronin]

Quote:

I  am trying to figure out if the O2 is going to benefit me and could us some help. I have heard other amps such as the audio gd sparrow with a very powerful 10v output and I was never able to tell a difference or pass a blind test with it against my computers onboard sound. Because of this I am doubtful I am goIng to hear any difference with the O2. Is there any reason the o2 will do something for me these other amps did not? Thanks.

If your onborad has enough power for you then you probably won't notice a difference by adding the O2 in between

 

[Crazy*Carl]

It's quite powerful. My iPod usually is about at 75% volume but the pc is around 25% for normal listening

 

[maverickronin]

Well the O2 is all about clean power, low noise, and low output impedance.  The 580s aren't going to be bothered by any output impedance an onboard sound card is likely to have and isn't sensitive enough for you to hear the noise floor so if you've got enough power then you probably don't need the O2

 

[Crazy*Carl]

Do you think it's more likely to affect a denon ahd2000?

 

[maverickronin]

Quote:

Do you think it's more likely to affect a denon ahd2000?

Yeah.  They're sensitive enough that there might be some audible hiss and a few ohms of output impedance could end up making the bass sound loose or boomy.
 
An O2 would help with those issues.

 

[Crazy*Carl]

Does an iPod have a low output impedance That I could compare my pc to?

 

[sonitus mirus]

According to the references I could find, the iPod headphone output impedance is about 5Ω and the line out is 100Ω.
 
http://members.chello.nl/~m.heijligers/ipod/Performance/measurements.html

 

[maverickronin]

Which one?  For the most part they're all different and I don't have all of them memorized.

 

[Crazy*Carl]

I just tried my beyer earbuds and they did not sound any different on my pc vs iPod 
 
Iphone 4

 

[shotgunshane]

 
Quote:

I just tried my beyer earbuds and they did not sound any different on my pc vs iPod 
 
Iphone 4

As far as I recall, the iPhone 4 has .9 ohm. 

 

[Crazy*Carl]

So I take it denons run really well outa iPhone 4

 

[Anaxilus]

Not to derail the O2/iDevice dialogue but just wanted to toss out an idea for a Voldemort project.  Electrostatic amp.  I'd really really be curious to hear what could be done on the cheap w/ his measurement routine.  If someone finds the idea compelling perhaps they could give a shout out over on the blog.

 

[mikeaj]

 
Quote:

Not to derail the O2/iDevice dialogue but just wanted to toss out an idea for a Voldemort project.  Electrostatic amp.  I'd really really be curious to hear what could be done on the cheap w/ his measurement routine.  If someone finds the idea compelling perhaps they could give a shout out over on the blog.

Now that's an interesting idea I haven't heard, but I doubt it would come to pass.  My impression is that he fancies himself foremost as the champion of the little guy--or starting audiophile, or just borderline regular consumers.  Hence there's the focus on FiiO amps and DACs, all those sub-$40 DAC reviews, the aggressive rhetoric (which probably turns off many who have been around for a while, but may make a stronger impression on those whose opinions have not hardened as much), and so on.  Additionally, he markets the O2 as a kind of one-size-mostly-fits-all solution.  I don't get the feeling he would ever spend time designing for a niche of the niche audio market, which may be unfortunate for the Stax crowd.