[Chris J]

Quick question, I listen trough 3 different drives one Onkyo cd the other 2 are DVD drives and the O2 works great on all of them... seems to have plenty of power. What is the typical output of a stand alone cd player? I want to say it's 2V but am not sure. How does this affect the output while listening to a headphone like the DT880 600ohm? 
You can give me the 4th grade version so I can understand it

thanks

I'll give you the 8 Grade version...

Standard output voltage at full scale, i.e. the highest output you can get from the analog out (i.e. Line Out) of a typical CD player or DVD player is typically 2 Volts.
But the average level of music from the Line Out is closer to 0.2 or .04 Volts.

Simplest way to think of this is for me to tell you what I typically did when I had 600 Ohm DTs:
when I had a FiiO E17 I usually set the Gain to 16 dB or a gain of X 6.5
when I had a Matrix M Stage headphone amp I set the gain to either 10 or 18 dB so I could get a reasonable amount of volume control travel, somewhere around 12 o'clock
10 dB means a gain of X 3.1
18 dB means a gain of approx. X 8.5

0 dB of gain was never enough.
I was always turning the volume to approx. 5 o'clock
0dB of gain means 1 Volt at the input equals 1 Volt at the output (the headphone jack) when the volume control is set to full.

 

[Chris J]

Most, but not all, home stereo and theater components put out a 2 volt signal.  If you have your 02 set to 2.5x gain, you will have 5 volts max, at 6.5x gain, you will have 13 volts max.  That should be enough to properly drive nearly all dynamic headphones with plenty of headroom for peaks.

I just noticed you also answered his question, I'll have to edit my answer! :eek:

Just for comparison with my reply:

A gain of X2.5 = 8 dB of gain
A gain of X6.5 = 16 dB of gain

 

[Bill-P]

  I share some of your views, with shy recordings you only need more gain, otherwise, there's extra power in the amp that you can't use.
 
The main problem I see is that increasing the gain, what you get is a clipping machine, that will work best with shy recordings and just as good with loud recordings, but folks with no audio knowledge (the vast majority) would just crank up the volume and hear distortion at unhealthy levels.
 
That's indeed the case with Fiio E10, in 'High Gain' it starts clipping quite soon with most recordings (potentiometer at 70%).
And despite the E10 being much more powerful than a smartphone or ipod, and despite being a product for a much smaller and knowledgeable market, I've seen people with 250 Ohm Beyers complaining about clipping at those high levels.

 
That's not surprising.
 
The Fiio E10, IIRC, runs on USB power, which is about 5V. Unless Fiio used some clever trick with their power supply section, the voltage out of a USB port does fluctuate to be lower than 5V. So barring any other issue with noise and other things, that means the Fiio E10 can only guarantee about 2.5Vrms of output in the ideal case, but more likely around 2.0Vrms in most cases, or a gain of 2x in most cases. If you increase the gain, it'll cause the amp to clip, as there is no way it can deliver more than 2Vrms with only so much power to tap into. That's why an external amplifier with its own power supply, be it battery or walwart, would still do much better here.
 
There is a way to guarantee a higher voltage output coming from a USB slot, of course, but this requires more engineering chops, and it'll increase pricing, if nothing else, so that's something I think they would avoid.

 

[Chris J]

That's not surprising.

The Fiio E10, IIRC, runs on USB power, which is about 5V. Unless Fiio used some clever trick with their power supply section, the voltage out of a USB port does fluctuate to be lower than 5V. So barring any other issue with noise and other things, that means the Fiio E10 can only guarantee about 2.5Vrms of output in the ideal case, but more likely around 2.0Vrms in most cases, or a gain of 2x in most cases. If you increase the gain, it'll cause the amp to clip, as there is no way it can deliver more than 2Vrms with only so much power to tap into. That's why an external amplifier with its own power supply, be it battery or walwart, would still do much better here.

There is a way to guarantee a higher voltage output coming from a USB slot, of course, but this requires more engineering chops, and it'll increase pricing, if nothing else, so that's something I think they would avoid.

NWAVGuy measured 1.55 Volts max with 32 Ohm cans.

 

[Bill-P]

NWAVGuy measured 1.55 Volts max with 32 Ohm cans.

 
32 Ohm would cause a current limit, so I'd suspect the upper limit for lower current loads (higher impedance) may be higher, still.
 
Of course, it depends on what op amp is used as well, as some op amps can swing quite close to power supply, while some are so poor that they can only reach a certain percentage. If the Fiio E10 is really 1.55V max, that means it's even worse than I thought. They could have tried harder.
 

 

[Chris J]

32 Ohm would cause a current limit, so I'd suspect the upper limit for lower current loads (higher impedance) may be higher, still.

Of course, it depends on what op amp is used as well, as some op amps can swing quite close to power supply, while some are so poor that they can only reach a certain percentage. If the Fiio E10 is really 1.55V max, that means it's even worse than I thought. They could have tried harder.

10 kOhm load maxes out at 1.65 Vrms........sorry, that's all you can get from an SE output @ 5 Volts DC!

Don't forget:
5 divided by 2 is 2.5 Volts peak.
2.5 divided by square root of 2 is approx. 1.7 Vrms.

 

[Me x3]

   
32 Ohm would cause a current limit, so I'd suspect the upper limit for lower current loads (higher impedance) may be higher, still.
 
Of course, it depends on what op amp is used as well, as some op amps can swing quite close to power supply, while some are so poor that they can only reach a certain percentage. If the Fiio E10 is really 1.55V max, that means it's even worse than I thought. They could have tried harder.
 

 
That's because it's current limited down there.
 
Fiio E10 is capable of 2.5 Vrms into loads over 80 Ohm.
(Less than 1% THD)
 
2.6 Vrms into 600 Ohm load

 

[Me x3]

2.4 Vrms into 80 Ohm loads and 2.51 Vrms into 600 Ohm loads if you want less than 0,01% THD

 

[pp312]

I'm just wondering what they're writing about in the Headphone Amps Forum. Headphones probably.

 

 

[Argyris]

  I'm just wondering what they're writing about in the Headphone Amps Forum. Headphones probably.

 

 
Best post I've seen all day.

 

[macm75]

I posted this on the DIY forum a few days ago.  My amp is specific to high impedance HP's - DT880 is the 600ohm version.
Took me years to get to this point - trading lots of HP's - until I hit this combo - that was 3 or 4 years ago and I have not looked back since.  Sorry not necessarily discussion - more of appreciation.
 

 

[Argyris]

  I posted this on the DIY forum a few days ago.  My amp is specific to high impedance HP's - DT880 is the 600ohm version.
Took me years to get to this point - trading lots of HP's - until I hit this combo - that was 3 or 4 years ago and I have not looked back since.  Sorry not necessarily discussion - more of appreciation.
 

 
Actually, I like this kind of appreciation. That's a lovely looking amp there, the kind of device I'd like to have just for the looks, even if it didn't really improve my listening experience enough to justify the cost.
 
That's kind of how I feel about any amp upgrade at this point--I'm just fine with how my DT880 sounds at the moment, so it would feel like I was missing out on something I actually wanted a lot more if I went ahead and bought a different amp.
 
That all said, there's something about a nice simple box with the larger components sticking out on top that speaks to my aesthetic taste. I would personally put some kind of metal shield on mine, though, to protect the circuit from interference and, more importantly, to protect the components from possible damage or the occasional errant touch.

 

[Me x3]

  I'm just wondering what they're writing about in the Headphone Amps Forum. Headphones probably.

 

Please don't check that forum! Haha! =D
 
Back on topic: DT880s!
Great headphones by the way!
 

 

 

[Allucid]

It's funny, my iPhone 5 can drive my 600ohm Beyers really clean, with a lot of volume to spare.

 

[Brooko]

It's funny, my iPhone 5 can drive my 600ohm Beyers really clean, with a lot of volume to spare.

 
You'll get enough  volume because the DT880's aren't actually that hard to drive in terms of current.
 
But try (after volume matching) comparing (quick switching A/B) with them on iPhone 5 vs a decent amp like the NFB-12 or LD MKIV, and pay particular attention to the bass response. What the 600ohm need is a good voltage swing - and unfortunately the iPhone 5 is a little limited in this area.  It's only after volume matching and paying particular attention to the bass that you notice it.
 
Just my 2c.