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From: len@qumix.UUCP (Leonard Labar)
Newsgroups: fa.info-mac
Subject: Mac speaker
Message-ID: <147@qumix.UUCP>
Date: Sun, 28-Oct-84 19:16:23 EST
Article-I.D.: qumix.147
Posted: Sun Oct 28 19:16:23 1984
Date-Received: Sat, 3-Nov-84 08:21:58 EST
Distribution: net
Organization: Qume Corp., San Jose, CA
Lines: 25


Subject: Mac speaker

Apple says not to try hooking up a large speaker directly to the jack
in the back since the Mac isn't supposed to be able to drive that much
of a load.  Well, not having "inside Mac" and not knowing better I
decided to try anyway.

First I tried using a cheap transistor radio as an amplifier and
hooking up a 4" low compression car speaker that I had laying around.
The results were terrible, even without the Mac.  It could barely drive
the speaker.  Then I tried matching it to the Mac.  After an hour of
trying different resistor and capacitor combinations I gave up.  The
Mac severly overdrived the radio input.

Then I hooked the 4" speaker directly to the Mac.  The results were
astounding.  Plenty of volume and very little distortion.  I used extra
parts on hand i.e. I took a tv earphone set and cut the earphone off.
Just about anything will do.  The speaker came in a plastic enclosure
which seems to help the sound quality.  This is portable and a lot
better than lugging my stereo out to the garage.

Note:  If you decide to try this.  The secret seems to be the 4" low
compression speaker.  I don't guarantee the results if you try anything
larger.