>I asked a question about LINE OUT on mini disks and have done some
>more investigating. Bear in mind that I am not experienced with
>circuitry. I am using a Sharp DR-7. The manual does not give
>explicit directions
>regarding LINE OUT but in the specifications it lists a value for
>the LINEOUT.
>Specified output
> Maximum output level Load impedance
>Earphones - 8 mW + 8 mW 32 ohms
>LINE 250 mV (-12 dB) - 10 k ohms
>
>Are these different values?
>
>The recorder does not have a separate jack for LINE OUT but it looks
>to be incorporated with the headphone jack. The headphone jack has
>a 3.5mm four conductor plug and additional flat conductors in the
>elongated plug. I believe the four conductors are + and - for each
>channel. I think the additional connectors are for the remote
>commands.
Right. I downloaded the manual and had a look at it. I've never seen
this 4-pole headphone scheme before. I can't imagine any advantage to
the consumer of not having a common return for headphone channels. I
think it's marketing hype.
>The thing that is confusing me is how can I use the headphone jack
>with three conductor headphones or the remote with four conductor
>and have no apparent change in output volume when the specifications
>list different values for headphone and LINE OUT. I would not think
>the machine would not know the difference between a three conductor
>headphone and a three conductor patch cable.
It doesn't. They don't seem to say anything about "line out", but the
illustration implies that's what they mean when the 4-to-3 adaptor
cable is plugged in. I don't know what the point of that cable is,
since the jack is designed to work with 3-conductor plugs, too.
Perhaps it has a pad in it to protect the headphone amps from being
shorted. This can be a problem with hi-fi systems; many preamps and
receivers short out inputs when the selector switch is in a different
position, e.g. shorting the AUX IN when FM is being listened to.
Transferring with a 3-conductor cable right out of the headphone jack
will be fine.
-Dan Dugan
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