[ARC5] Added 6F6 audio stage.

[Glen Zook]

I use a speaker from a long forgotten "hi fi" stereo system when checking ARC-5 / SCR-274N receivers.  There is plenty of audio when the audio output transformer is tapped for "low".

A few weeks ago, I "recapped" my BC-453, BC-454, and BC-455, and checked them using this speaker.  The speaker has a nominal impedance of 8-ohms.

Even more audio is possible if a matching transformer is used.  A small 12.6 VAC filament transformer with the primary connected to the audio transformer in the receiver and the secondary connected to the speaker works very well.  A 6.3 VAC transformer can also be used.  The 12.6VAC matches an 8-ohm speaker pretty well and a 6.3 VAC matches a 3.2-ohm speaker pretty well.  But, using either transformer with either speaker impedance will also work and the difference is not really noticeable!
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: David Stinson <arc5 at ix.netcom.com>
To: ARC-5 List <arc5 at mailman.qth.net> 
Sent: Friday, October 19, 2012 8:15 PM
Subject: Re: [ARC5] Added 6F6 audio stage.
 


> BUT youre only concerned about yourself, not others.

Never had anyone standing here gripe about it.

Sincerely- I've never had the problem of low audio 
in a properly-working receiver and I wonder why 
some folks do.  I'm probably missing something.