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Line out dock and portable amplifier - Page 3

post #31 of 45
Quote:
Originally Posted by Gryphus0204 View Post

I was planning to buy an amp for the v-moda m-100 which is comming up soon


Thanks.  Can I make a suggestion then.  As far as I am aware (just waded through the incredibly long M100 thread) - the M100 looks as though it will be fine without an amp, but will probably scale up with an amp.  Until we actually know for sure what it's impedance and specs are - why not simply wait until it's released.  Then wait and see what first impressions are like before committing to an amp.  There's enough hype around the M100 launch - and I'm guessing there will be quite a few head-fiers with a variety of amps at their disposal.  You'll be able to question them directly - and more importantly they'll have first hand experience with that particular headphone and the amps they have available.  Then you can get actual advice from someone who's heard that specific can with a specific amp.

 

In the meantime - you can still enjoy an unamped M100 - and then get the right amp - rather than relying on advice in this thread from people who have never heard the M100 because it hasn't been released yet.

 

Or - you could make it a popularity contest, take the advice available so far - and take your chances.

 

If it was me - I'd be more inclined to wait and buy wisely wink.gif.  Of course it's not me though smile.gif - so I'll back out now and let you decide .....

post #32 of 45

Then why does the signal from the LOD seem to be MAX AMPLIFIED at 100% volume??

 

Directly connecting my headphone to the LOD would result in mind numbing volumes. I thought its 'unamped' :)

post #33 of 45
Quote:
Originally Posted by wilzc View Post

Then why does the signal from the LOD seem to be MAX AMPLIFIED at 100% volume??

Directly connecting my headphone to the LOD would result in mind numbing volumes. I thought its 'unamped' smily_headphones1.gif

Because, not just you but many in the forum as well, misunderstand that amplifier must 'amplify' the signal all the time, which is actually not true at all. DAC's output is always (preferably) on line-level because that's the best possible signal with minimum distortion (which is the reason it is 'line-level' in the first place). Amplifier's job is to control the voltage and current supply to the headphone (*actually driving the headphone), giving headphone the adequate power it needs. Even with less than 1x of gain, an amplifier is still an amplifier. Just because someone calls himself Jesus doesn't mean he is divined, same reason. *Excuse me for the example.

Also, line-level and max amplified are two different things. Saying them are the same is like saying a muscular man must have hit the gym a lot. He could just happen to have a very physically demanding job. Just because a signal is high in amplitude doesn't mean it has been amplified.
Edited by ClieOS - 5/7/12 at 10:43am
post #34 of 45
Quote:
Originally Posted by wilzc View Post

Then why does the signal from the LOD seem to be MAX AMPLIFIED at 100% volume??

 

Directly connecting my headphone to the LOD would result in mind numbing volumes. I thought its 'unamped' :)

 

It's not that simple. 'Amped' or 'amplified' doesn't simply mean 'multiplied' - there's a part of a headphone amplifier called a 'preamp' stage. Depending on a circuit, this can either be very complex or as simple as just the potentiometer, either way the basic function of a preamp is to control how loud it goes. I can't remember the more technical part of this, but I think it actually controls (reduce) the voltage of the incoming (input) signal. A typical speaker system for example would have a preamp and a poweramp, and when these are integrated into a single box (but can be designed with separate power supplies), it's called an integrated amp. This is typically what headphone amplifiers are.

 

On playback devices, let's contrast a conventional HiFi or professional CDPlayer and a typical portable player. A CDPlayer might have dual DACs (one for each channel), an opamp/HDAM or tube output analog stage with a 2volt standard signal, and maybe a headphone amplifier stage with a tube or chip and the supporting circuit driving a headphone. The S:Flo is basically a miniaturized version of all this. Your typical portable player would have most if not all of these integrated into a single audio processing chip. Where the S:Flo would have two Wolfson WM8740, opamps in the analog stage after that for the lineout or into a Philips TDA1308 headphone driver, a Samsung or Cowon would have a single Wolfson WM8994.

 

Depending on the capabilities of a given audio processor and the circuit design, some players might still have some functions handled by another component after the integrated audio chip, in which case a 'bypass' lineout basically means you skip the potentiometer for the headphone out. Where the audio processor basically handles everything audio related, it either bypasses the preamp circuit in the chip, or if it uses fully digital preamplification*, simply shuts off any control over the volume. In some cases the thing with these do-it-all audio chips is they have a DAC and a headphone amp, but usually nothing like an opamp/HDAM in them (why would a manufacturer assume the typical user would have a headphone amp that needs a lineout?), so the "lineout" is basically just that - "full volume" in the sense that the digital preamp is off and you get the signal from the DAC at its max setting. In some cases the chip was either designed with this in mind or simply had clean enough output; my Cowon S9 and Galaxy S are good used this way with amps. In other cases, well, no; I hated the noisy and tinny analog "lineout" of my iPod Touch.

 

So basically, you are right that "unamped" in a sense is volume from the DAC, but there's a reason why full-size players have an opamp/HDAM or tube analog stage past the DAC, and not just the DAC directly soldered into the output jacks; and yet neither does "amped" have to be "louder" per se, but simply that a 2V low-level signal would have to be made into, say, high-level signal measured in Watts (or fractions of it, mW, for headphones).

 

 

 

*and not just digital control, but there is an actual preamp circuit somewhere in or out of the audio chip

post #35 of 45

I have actually read somewhere where someone claimed that the apple's line out using LOD cables are not 'true' line outs.

 

Which was the basis of why iMods exist. Not sure.

post #36 of 45
There are various design across different genarations of iPod, some are better than others. But as far as the current iDevices goes, I think it is a fair to say they are all quite good.
post #37 of 45

hey guy, thats a common misconception. the LOD does bypass a lot of circuitry which causes interference to the signal...but without using the internal amp and dac there would be no sound. A portable player doesnt produce the same sort of lineout that a Hifi player can-> this is because they are not intended for that use by the manufacturer.

Quote:
Originally Posted by bowei006 View Post


 



line out dock is a cable. it is generally for ipods. the name itself is general but it also..implies for use with ipods as other devices either don't have an LOD or just have an Line out..not all. walkamns also have an LOD by fiio now

 

im going to assume u have an ipod:

in your ipod or portable media player you have an DAC and an amp. The DAC in your ipod is good and clean but the amp isn't. the amp muddies up the signal and adds distortion(higher volumes), hiss, noise and artifacts to the signal. What an LOD does is it bypasses the amp and internal headphone jack circuitry giving you a dirrect line from the DAC into your external amp. a LOD does not amplify. it is the bridge that connects the clean analog signal from the DAC and sends it to your external amp. you NEED to use an external amp with an LOD as since you bypaseed your internal amp..you now need an amp.

 

some LOD's have built in amps..by FiiO, you don't realy need to look at those.

 

amps amplify. lod's by themselves do not.

 

here is a video


Edited by Mr_Junesequa - 5/8/12 at 5:28am
post #38 of 45

sorry meant portable player. bottom line both the dac and amp need to be used to produce sound from 99.9% of portable players.


Edited by Mr_Junesequa - 5/8/12 at 5:29am
post #39 of 45
Quote:
Originally Posted by ProtegeManiac View Post

 

It's not that simple. 'Amped' or 'amplified' doesn't simply mean 'multiplied' - there's a part of a headphone amplifier called a 'preamp' stage. Depending on a circuit, this can either be very complex or as simple as just the potentiometer, either way the basic function of a preamp is to control how loud it goes. I can't remember the more technical part of this, but I think it actually controls (reduce) the voltage of the incoming (input) signal. A typical speaker system for example would have a preamp and a poweramp, and when these are integrated into a single box (but can be designed with separate power supplies), it's called an integrated amp. This is typically what headphone amplifiers are.

 

On playback devices, let's contrast a conventional HiFi or professional CDPlayer and a typical portable player. A CDPlayer might have dual DACs (one for each channel), an opamp/HDAM or tube output analog stage with a 2volt standard signal, and maybe a headphone amplifier stage with a tube or chip and the supporting circuit driving a headphone. The S:Flo is basically a miniaturized version of all this. Your typical portable player would have most if not all of these integrated into a single audio processing chip. Where the S:Flo would have two Wolfson WM8740, opamps in the analog stage after that for the lineout or into a Philips TDA1308 headphone driver, a Samsung or Cowon would have a single Wolfson WM8994.

 

Depending on the capabilities of a given audio processor and the circuit design, some players might still have some functions handled by another component after the integrated audio chip, in which case a 'bypass' lineout basically means you skip the potentiometer for the headphone out. Where the audio processor basically handles everything audio related, it either bypasses the preamp circuit in the chip, or if it uses fully digital preamplification*, simply shuts off any control over the volume. In some cases the thing with these do-it-all audio chips is they have a DAC and a headphone amp, but usually nothing like an opamp/HDAM in them (why would a manufacturer assume the typical user would have a headphone amp that needs a lineout?), so the "lineout" is basically just that - "full volume" in the sense that the digital preamp is off and you get the signal from the DAC at its max setting. In some cases the chip was either designed with this in mind or simply had clean enough output; my Cowon S9 and Galaxy S are good used this way with amps. In other cases, well, no; I hated the noisy and tinny analog "lineout" of my iPod Touch.

 

So basically, you are right that "unamped" in a sense is volume from the DAC, but there's a reason why full-size players have an opamp/HDAM or tube analog stage past the DAC, and not just the DAC directly soldered into the output jacks; and yet neither does "amped" have to be "louder" per se, but simply that a 2V low-level signal would have to be made into, say, high-level signal measured in Watts (or fractions of it, mW, for headphones).

 

 

 

*and not just digital control, but there is an actual preamp circuit somewhere in or out of the audio chip

thanks, I think that I need to read this more

Quote:
Originally Posted by wilzc View Post

I have actually read somewhere where someone claimed that the apple's line out using LOD cables are not 'true' line outs.

 

Which was the basis of why iMods exist. Not sure.

Clieos said something like that, more than 4 years ago

http://www.inearmatters.net/2008/12/to-amp-or-not-to-amp.html

 

take a look at here , maybe helps

 

http://www.head-fi.org/t/592032/line-out-difference-an-ipod-touch-3g-vs-ipod-classic-5g

post #40 of 45

fiio's amp is poor

post #41 of 45
Quote:
Originally Posted by IamChinese View Post

fiio's amp is poor

Easy for you to say something is poor, but what do you compare it to and how do you draw your conclusion from?
post #42 of 45

I want to compare it to other amp actually..

But my English is as poor as fiio's amp.blink.gif

You can compare it to ibasso'amp or RSA's amp..

biggrin.gifThen you know I am right

post #43 of 45

Seems fiio very popular here blink.gif

post #44 of 45
Quote:
...Then you know I am right

It is not about whether you are right or not, but the validity and fairness of your opinion to a product. You are essentially comparing more expensive amp to cheaper amp, what else do you expect? I could have said a Honda Civic is trash compared to a Ferrari, but it would be just as pointless as your previous comment in a car forum.
post #45 of 45
Quote:
Originally Posted by IamChinese View Post

Seems fiio very popular here blink.gif


The FIIO range are very good for the price, there are of course better amp at much higher price, but not everyone want or can afford them.

 

Also DAC in the ipad2 and new ipad can be bypassed with the camera connection kit, and works with some amps, but couple of portable amps I tried don't work.

 

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