Headphones out to line out

I have the same sort of problem... left ear severely dinged, about 30 years ago, by over-pressure while testing a hearing aid compressor circuit, by hammering on the bench while the earphone was in my ear... blew a hole in my eardrum :-(

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Benjamin,

The most likely reason is that you have the volume of the MP3 player too high - try setting it lower then putting the volume of the amplifier up.

Most people find that MP3's encoded at 128Kbits/sec or higher are of reasonably good quality with rates above 192kbits/s being considered indistinguishable from CD quality.

I usually use 128K-192K for music and 32K for voice recordings and find they are perfectly acceptable in the home, in the car and on headphones.

kevin

You must have a lousy radio.

Kal

Considering that speech is pretty recognizable over POTS at 7-bits by

8KHz (and far less than that usefull for *many* years), 32K should work with some intelligent compression.

--
  Keith

Just a guess; Are you an Audiophool?

--
  Keith

My mp3 player only has a headphone jack. I suppose that is a current signal? When I hook it up to the amplifier it sounds fuzzy. I guess it's because it should be a voltage signal?

Is there a way to transform headphones to line out without turning the world upsidedown?

Benjamin

Hello Martin,

I don't have an MP3 player but I have heard that before. Why then is MP3 all the rage? Just because of the amount of songs that can be crammed into a gigabyte?

Regards, Joerg

MP3== fuzzy audio

martin

Hello Jim,

For speech they must be great. Even with music I am not too critical since I listen to shortwave and AM a lot. Quality checks I have to do on one ear since the other got a ding in the army when something went weeeooouuu-kaboom.

Regards, Joerg

Hello Kevin,

Cell phone companies seem to think that a fraction of that 32K should be acceptable :-(

Regards, Joerg

Benjamin,

I use the headphone out on my Creative NuVo to drive amplified speakers and it works pretty good. Remember that the signal out of the MP3 player might no be large enough to drive speakers directly. Are you running the headphone out into an amplifier? If so, did you adjust the volume on MP3 player to different levels?

MP3 ain't CD quality, but its as good/or better than most radio to me.

-- snipped-for-privacy@hotmail.com remove "xyz" to email me directly

MP3's aren't fuzzy, but I've heard quite a few with a strong wishy-washy sound (mp3's have many of the same artifacts as FFT-based noise reduction that audio editor programs use). But yes, mp3's give 'most' of the sound of a CD [it's apparently indistinguishable to many people] for ten percent of the storage of CD's.

To the original poster, it's not a current vs voltage thing. It's possible the mp3 player is output too high a voltage for the line input. Does the fuzziness go down or disappear when you turn down the volume on the mp3 player? If so, leave it down.

-----

There's no such thing as a 'current' signal the way you're thinking it seems in audio.

In any event all outputs have to have a voltage to make the current flow !

The headphone out *will* be a voltage signal btw. And indeed you can use it to drive a power amplifier with no modification.

I don't know why you have a problem, other than perhaps the fact that a decent external amplifier and speaker may accentuate the rather poor quality of mp3.

Graham

More likely because it enabled the download of loads of tracks for free off the net. And yes, the smaller storage size helped too.

Some ppl also like to be able to fit 50-100 tracks on a CD-ROM.

The detail that mp3 can lose is quite remarkable in some instances.

Graham

Did you get any compensation for that ?

Graham

Yep, You're right, it needed a capacitor ;-)

Seriously, I was already a consultant... dinged on my own dime.

The design is one I have posted on A.B.S.E in the past. Works quite nicely, even at 0.9V

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

That depeds on the compession of course. I have read about tests where "audiophiles" got to listen to an top-notch CD player and an MP3 recording. Many of them couldn't tell the difference and some even chose the MP3 recording to be the best.

Meindert

Any current source (if it is at all a current source) is transformed into a voltage source by a simple load resistor. To connect a 33 ohm resistor to the output as a dummy load and hook up the amp from there.

Meindert

Overdriving the amplifier into clipping because of too much voltage from the MP3 player, perhaps.

Turn the volume down on the player and see if it sounds any better.

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)