[greenhorn]

Can anybody explain me the following, please?

The logic says that a poor quality audio signal, when amplified, will remain of poor quality.

The signal coming from a jack output of a smartphone is of relatively poor quality. I mean, collecting the audio signal from the headphone output of a smartphone is more or less like collecting it from the headphone output of a CD player (instead of collecting it from the line outputs of the CD player).

However, when amplified through a portable amp, that smartphone signal clearly improves in quality.

How is this possible? It just contradicts the principle «you can’t make a silk purse out of a pig’s ear »… or « you can’t turn crap into gold » .

 

[msing539]

Are you referring to a 3.5 jack out vs. a portable usb c dac?

 

[greenhorn]

No DAC involved. All analog.

headphone analog output of a smartphone -> headphone amp (analog input) -> headphones

and it gives BETTER sonic results than:

headphone analog output of a smartphone -> headphones

Why?

 

[greenhorn]

Double post.

 

[ClieOS]

You don't think an amp will drive the headphone better than the smartphone? The two main factors why most smartphones don't drive headphones well are 1) poor quality (*SNR, dynamic range and crosstalk) analog signal and 2) poor output power. Adding an amp will (*should) improve factor 2.

 

[greenhorn]

You don't think an amp will drive the headphone better than the smartphone? The two main factors why most smartphones don't drive headphones well are 1) poor quality (*SNR, dynamic range and crosstalk) analog signal and 2) poor output power. Adding an amp will (*should) improve factor 2.

That’s my point.

The smartphone feeds a poor quality signal to the amp (which means that the amp receives a poor quality signal).

How can an amp « improve » it?

An amp can deliver a good signal to headphones IF it’s fed with a good signal itself. This is possible through a line level input. But a smartphone doesn’t have a line level output.

So the amp is fed from the headphone output of a smartphone, which - as everybody agrees - is a poor quality signal.

 

[Rackhour]

Are you sure you aren’t falling into the “louder = better” trap? An amplifier’s job is solely to amplify the sound. By that logic, annoyances become louder annoyances and good bits become even better bits.

What is your equipment chain like that made you realize this? Which phone, amp, headphone, etc.

 

[ClieOS]

That’s my point.

The smartphone feeds a poor quality signal to the amp (which means that the amp receives a poor quality signal).

How can an amp « improve » it?

An amp can deliver a good signal to headphones IF it’s fed with a good signal itself. This is possible through a line level input. Not from the headphone output of a smartphone, which - as everybody agrees - is a poor quality signal.

Let's go back to what I have said before - headphone sounds poor on a smartphone because of the sum of two things - (1) the poor analog signal decoded by the smartphone itself and (2) the poor performance of the smartphone output section driving the headphone. So when you listen to headphones on the smartphone, you are getting the sum of both (1) and (2). But by using an external amp, now you remove (2) and you should only get (1), thus the overall SQ should improve - how is that hard to understand? The point is, if you measured the basic SNR / dynamic range, etc of the amplified signal, you are still going to find the same (or often slightly worse) as the unamplified signal, and that's crap-in-crap-out. But now the headphone is better driven (by the external amp), and you'll get less crap in the end since (2) no longer adds more crap to the mix. The job of the amp is to drive the headphone with the proper voltage and current, it doesn't care about the SNR / dynamic / etc of the incoming signal. To the amp, there is no difference between poor SNR and good SNR, there are both voltage signals.

 

[greenhorn]

Are you sure you aren’t falling into the “louder = better” trap? An amplifier’s job is solely to amplify the sound. By that logic, annoyances become louder annoyances and good bits become even better bits.

What is your equipment chain like that made you realize this? Which phone, amp, headphone, etc.

Not sure at all. Maybe it’s just a placebo effect. It would be logical.

However, feeding youtube from an iPhone 6 to a Bowers & Wilkins P9 via a small Douk amp I just bought from aliexpress sounded (I think! ) much better (not louder!) than without the amp. And I just can’t understand why

 

[greenhorn]

Let's go back to what I have said before - headphone sounds poor on a smartphone because of the sum of two things - (1) the poor analog signal decoded by the smartphone itself and (2) the poor performance of the smartphone output section driving the headphone. So when you listen to headphones on the smartphone, you are getting the sum of both (1) and (2). But by using an external amp, now you remove (2) and you should only get (1), thus the overall SQ should improve - how is that hard to understand? The point is, if you measured the basic SNR / dynamic range, etc of the amplified signal, you are still going to find the same (or often slightly worse) as the unamplified signal, and that's crap-in-crap-out. But now the headphone is better driven (by the external amp), and you'll get less crap in the end since (2) no longer adds more crap to the mix. The job of the amp is to drive the headphone with the proper voltage and current, it doesn't care about the SNR / dynamic / etc of the incoming signal. To the amp, there is no difference between poor SNR and good SNR, there are both voltage signals.

Ah, now I understand better what you meant. Thanks for elaborating for a slow head-fier . Yes, it makes sense to me.

 

[coburn]

There may be another aspect to this. The amp will add power to both the signal and the noise. However, by amplifying both, it is easier for the human ear to distinguish signal from the noise. The s/n ratio is the same but psychological perception of the signal is interpreted as a 'cleaner' sound.

 

[Mooses9]

I definitely agree with no matter how good or bad the signL is, the perception of one's interpretation of the sound is really going to come down to it.

not to mention that is slightly the point of a Mp is to take a signal and make it better.

that goes for the complete chain amp,dac,cables,headphone,,/iem cables and then the headphones and iems of choice.

just my .02

 

[Claypole]

Could it be impedance related?

The output impedance of the phone might not be ideal for the headphones in question, but might be ideal for the headphone amplifier input. Then, the output impedance of the amplifier might be a better match for the headphones, giving a genuinely better sound.

 

[Mooses9]

well the one problem is that most amplifiers have low medium and high gains so one could adjust the gain output to correct the impedance input/output.