[Arny Krueger]

"Trevor Wilson" wrote in
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"Arny Krueger" wrote in message
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"Trevor Wilson" wrote
in message

As you correctly surmised, most non-headphone amp
equipped amplifiers use a 220 - 470 Ohm series resistor
to limit power to the headphones.

So far, so good.

What you may not know
is that most headphone amp equipped amplifiers use
similar value resistors in series with very cheap OP
amps to drive headphones.

Wrong.

**Cite your evidence.

I did, just below.

Most op-amp based headphone amps use far lower value
resistors, for pretty obvious reasons. They'd have to use a far more
expensive op amp and power supply if they used such a
large resistor. Series resistors are still often used,
but they are usually of a far lower value, for example
10-50 ohms. http://www.rane.com/pdf/hc4sch.pdf

http://www.rane.com/pdf/hc6sch.pdf

http://www.rolls.com/data/ha43man.pdf

http://www.headwize.com/projects/cmoy2_prj.htm

http://www.minidisc.org/schem.gif

http://sound.westhost.com/project109.htm

**Just reminder: We're discussing DOMESTIC audio
equipment. These guys use the cheapest, crappiest ICs
they can find. Usually, 4558 derivatives.

Cite your evidence - do what I did - post links to schematics.