[R-390] Anyone know what a 2C254 Audio Amplifier Module is?

[Bill Smith]

The module turns out to be the low-level audio stages of an ART-13
transmitter.  The toggle switch allows use of either a carbon or a dynamic
microphone.  I think the rotary switch is used to preset the sidetone level,
it selects one of six secondary taps on an output transformer.

The circuit is not push-pull, it turns out to be three amplifier stages in
series, a 12SJ7 is a preamplifier stage.  The first 6V6 with output
transformer is the driver for the 811 modulators and the second 6V6 with
another output transformer delivers sidetone audio.

73 de Bill, AB6MT
billsmith@ispwest.com

----- Original Message -----
From: "Kenneth Crips" <w7itc@hotmail.com>
To: <billsmith@ispwest.com>
Sent: Thursday, June 06, 2002 8:15 AM
Subject: Re: [R-390] Anyone know what a 2C254 Audio Amplifier Module is?


> There is a gentleman in FT Collins that builds Hi-Fi audio modules for
> R390A.  I have never seen one but I understand they sound great.
> could this audio Amp be one of those? If those 6V6's are in push-pull
> you are looking at about 8 watts or so audio output.  This is the setup
> My National 183D has.
>
> Meissner!
>
> Kenneth A. Crips W7ITC, Cheyenne, Wyoming
> Home of Chew Crew II, The Beez-Bomb,
> Chic' MOB (mother of Beezie), and
> the future home of Cowboy, whelped 4/11/2002
>
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at
http://explorer.msn.com/intl.asp.
>