[TenTec] Fw: Help Requested

[Paul Christensen]

Mike Gipe, K1MG,  has given me permission to post the following message from
the QRP-l reflector.  I thought there may be some interest in his
explanation of the audio bridging amp as I believe it is of the type used in
both the Jupiter and Pegasus.  Several folks during the past few months have
inquired about the inability to ground one side of the amp.  Here's why...

-Paul, W9AC

----- Original Message -----
From: "Mike Gipe" <mgipe@reliablemeters.com>
To: "Low Power Amateur Radio Discussion" <qrp-l@Lehigh.EDU>
Sent: Thursday, October 18, 2001 18:44 PM
Subject: RE: Help Requested


> Bridge amplifiers are now pretty common in integrated audio amp ICs.
> Essentially, a bridge amplifier drives two outputs with a differential
> signal; whereas a normal amplifier drives a single output referenced to
> ground.  With the bridge amplifier, you connect the speaker between the
two
> differential outputs; in a regular amplifier, you connect the speaker
> between the amp and ground.
>
> The advantage of the bridge amp is that you can get twice the output
voltage
> swing with a given power supply voltage, thus yielding four times the
power
> out.  With the lower voltage systems that now predominate in new designs,
> this is very important.
>
> Mike K1MG