Driving headphones from a line-out
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ToyTrains

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I'm the proud owner of a new DEJ1000, but am very disappointed with the quality of the headphone amp. Vastly inferior to even my minidisc recorder. Anyhow, I was listening to it last night and just for fun plugged my Beyer DT311's directly into the line-out. Now I know that there is a severe impedance mismatch, but the sound was great! Clear, defined highs, smooth bottom-end, and fairly loud. Using that along with an in-line volume control seems to be perfect.

Any one have any thoughts on this? I do have a concern about damaging the line out through feedback from the 'phones, but am not sure about this.

BTW, the DT311's are older, I bought them in fall of 1994.
 
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Eagle_Driver

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First, I wouldn't try driving headphones directly from the line-out of any portable device.
Those line-outs have a reeeeeaaally high matching impedance (at least 10,000 ohms) - and your headphones have roughly a 250-ohm impedance. Thus, that line-out is really designed for an external audio device, such as an external amp or a tape/Minidisc deck.

Second, I agree that the headphone-out blows on the D-EJ1000. My particular one distorts/clips with most earbuds when the volume is turned up past half-way. So forget about using EX70LP's with the D-EJ1000, since they're both low-impedance and low-sensitivity. But strangely, it doesn't clip much with my Koss KSC-35 earclips or my Sennheiser HD590 'phones.

Unfortunately, in this $150-and-up non-MP3/non-"Sports" PCDP segment, the only other U.S.-market alternative to the Sony D-EJ1000 is the Panasonic SL-CT790, which (for the U.S. market) lacks even a line-out, let alone switchable anti-skip. I was really disappointed that this $150 model has compressed anti-skip that can't be turned off at all, and has only a mediocre-sounding headphone jack as its only audio output.
 
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dinosauract

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Eagle_Driver -

Is it possible to actually damage the portable device by connecting headphones to its line out? I wouldn't think it was. I could see possibly damaging the phones due to a clipped voltage signal if the mismatch is too great. But I think long before any damage is done, the sound quality would suffer so much that you wouldn't listen this way anyhow.

Its hard to know exactly what the output impedance of the Sony's line out jack is. This can vary tremendously from one design to another.

I think if it were me, and I liked the sound this way, I would go for it. Maybe I'm missing something though?
 
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sTaTIx

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Quote:

Originally posted by Eagle_Driver
Those line-outs have a reeeeeaaally high matching impedance (at least 10,000 ohms) - and your headphones have roughly a 250-ohm impedance.


And this is bad, because...?
 
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Eagle_Driver

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...the potential for screwed-up (incoherent) sound exists.
 
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skippy

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i think what eagle driver meant to say is that the line out was designed to be connected to equipment with high impedances, above 10kohms or so, not the acutal output impedance of the line out. since the impedance of the headphones are so low in comparison, the headphones will draw much more current. line outs aren't designed to power headphones and may not have good current capabilities. it's possible to fry the line out by drawing too much current, but i highly doubt it. most likely the sound will just distort.
 
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AssafL

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Using a Line Out is unlikely to cause damage. Line Outs on portables are usually designed to accomodate for the ignorant user who plugs his cans into the line out... It only takes a resisitor in series...
The advantage of a line out is the higher voltage (hence better at running a high impedance headphones).
 
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