What exactly is a "true line-out"?
Mar 27, 2004 at 10:17 PM Post #2 of 10
Generally.. on digital devices, it would be the "raw" analog signal right after it has been processed by the internal DAC (digital/analog converter). If it's right after the DAC.. it's a true line out.

Volume control doesn't necessarily have anything to do with it.

[edit: To answer your original question, you really have to look at the layout or the schematic.]
 
Mar 27, 2004 at 10:45 PM Post #3 of 10
A true line out (on a portable device) should have a separate jack from the headphone jack, in order to bypass the headphone amp circuits completely. The volume and EQ settings should not affect a line out - it should be as flat (pure) as possible. It should be marked appropriately as "line out" and mentioned in the manual.

On CD players that have this it's sometimes combined with a digital out. The Sony D-EJ2000 optical/line out isn't marked on the player, but tells you in the manual. In any case the line out should be separate from the headphone jack, otherwise at best it's a pseudo line out.
 
Mar 28, 2004 at 4:56 AM Post #5 of 10
Quote:

Originally posted by mikeg
The output of the Line Out of my iRiver IMP-350 SlimX is controlled by the volume control. Does this mean that it is not a true line out?


I can confirm that the iMP-350's so-called "line out" is not a true line out: Running RightMark on both the headphone out and the line out of that player produced virtually the exact same results for both outputs.
 
Mar 28, 2004 at 5:29 AM Post #6 of 10
Quote:

Originally posted by Eagle_Driver
I can confirm that the iMP-350's so-called "line out" is not a true line out: Running RightMark on both the headphone out and the line out of that player produced virtually the exact same results for both outputs.


Any idea why this unit bothers having a second (i.e., line out) output?
 
Mar 28, 2004 at 7:01 AM Post #7 of 10
The only TRUE line outs on portable players to the best of my knowledge, with the full, full sized player amount of voltage, is on the Sony D5, D7, and D14...

After that, the power was halved.. so makes the s/n ratio etc that much harder to get right.
 
Mar 28, 2004 at 1:22 PM Post #8 of 10
A "line out" signal is one which provides a nominal .775 V RMS signal (this is 1 mw into 600 ohms = 0 dBm). Peak level is usually +4 dBm, or about 1.23 volts. It has nothing to do with how it's connected internally, nor whether or not there's a means of level adjustment.

Any signal source which provides, or can be adjusted to provide, that level output can properly be called a "line out."

The term "line" originates in telephony, and later
broadcast audio.
 
Mar 28, 2004 at 1:44 PM Post #9 of 10
I'm not sure about the technical description, but the iRiver line-out is noticeably subdued (in terms volume AND dynamics) when compared with a D-555, Creative NJB3 and a Sony D-NE900 pseudo line out. Sounds muddier too.


The D-555 and NJB3 tie in best Line Out dynamics / volume. The NE900 is slightly worse, and the iMP-550 is left a way behind.


I still wonder why Headroom recommended these iRivers as suitable for amping. In my opinion you couldn't find a worse machine for doing that for the same money. Headphone out is a different matter... some may like the sound and it's not far removed from the HP/outs of many other current premium PCDP's but with a much better scope for EQ adjustment.
 
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