Re: the IIGS and speakers

[wrh3c@watt.seas.Virginia.EDU (William R. Hall)]

In article <42kcmd$lpt@nntp5.u.washington.edu>,
Ron Louie <ronlouie@u.washington.edu> wrote:
>
>	I've always had a bit of trouble with my external speaker 
>hookup...is there an explanation?  I bought a pair of cheap computer 
>speakers that connect in a single stereo mini-plug, which fits in the 
>headphone port....but they hardly play....unless I use a mono adapter.  
>Then...they hardly play...until I jiggle the plug and pull it half out 
>(this is the mono adapter, now)...and voila, great volume!  The set up is 
>umamplified, and I'm guessing they're 4 ohm speakers.  Should I just get 
>in there and replace the jack, or am I missing something?

  The jack is fine; the problem is the unamplified speakers you're
using.  The headphone port on the GS is meant for headphones, not
speakers.  The difference is that headphones have a higher impedance
(typically 32 ohms) than regular speakers (typically 8 or 4 ohms)
and require less power to get an audible signal.  The solution is
to use amplified speakers, or to connect a cable from the GS's
headphone port to a line-level input on your stereo amplifier.

  Additional note #1: You shouldn't need to use the mono adapter,
because the jack on the GS is a stereo jack, but with the same signal
applied to both the left and right channels.  This allows you to
connect stereo headphones and hear the audio in both ears.

  Additional note #2: I've noticed that the "plug jiggling" you
mention works on other speaker-equipped devices I've used over the
years.  I think this happens because of the way the jack and
internal speaker are wired:  when nothing is plugged into the
jack, the internal speaker produces sound, but when a plug is
inserted into the jack, the internal speaker is cut off.  If the
plug is inserted only part of the way into the jack, it is
possible to reach a point where connection has been made to the
signal at the jack, but the internal speaker has not yet been
disabled.  At this point, the audio amplifier is still driving
the internal speaker and is quite happy to drive your attached
speaker as well.  (Note: this is just my personal hypothesis.)
-- 
William R. Hall  |  wrh3c@watt.seas.Virginia.edu