[ARC5] Potentiometer value needed

[D C _Mac_ Macdonald]

I wonder if a concentric (dual) wirewound pot could be found to serve as both RF/IF gain AND audio gain controls.  OR a pair of miniature pots for that purpose? 
  
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk hotmail com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
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> From: brianclarke01 at optusnet.com.au
> To: kgordon2006 at frontier.com; radio-tuber at att.net
> Date: Sun, 10 Aug 2014 11:28:30 +1000
> CC: arc5 at mailman.qth.net
> Subject: Re: [ARC5] Potentiometer value needed
> 
> Hello Jim,
> 
> Because there is DC on the pot, if you use a carbon-tracked pot, it will 
> soon become noisy. It is far better to use a wirewound pot, as in the 
> original design.
> 
> If you plan to fit Ken's suggested AF gain control in the front of the 
> receiver, shield both audio leads.
> 
> 73 de Brian, VK2GCE.
> 
> On Sunday, August 10, 2014 7:47 AM, Ken suggested:
> 
> 
> > On 9 Aug 2014 at 14:21, Jim Falls wrote:
> >
> >> I have a lightly hacked (12 filament mod) silver BC-453-B with an on/off 
> >> switch,
> >> volume control and phone jacks in the front cubby hole. Current pot is 
> >> far to
> >> touchy and probably linear taper. What's a good value audio taper to use 
> >> for
> >> hi-Z phones/speakers? I'd like to try it with my TCS and others.
> >
> > Hi, Jim:
> >
> > That "gain control" is a combination RF/IF gain pot acting on the 
> > cathodes. I
> > have found that a 50K log (audio) taper pot works well there.
> >
> > Since you are, apparently, going to use that BC-453 as a "Q-5er" for your
> > TCS receiver, I suggest that you add an AF gain control to it.
> >
> > Use a 2 megohm (or a 1 meg) log-taper pot to replace R-20, the 12A6 grid
> > resistor, then connect the wire that attaches to the 12A6 grid connection
> > which comes from the flat .006 mfd capacitor to the pot wiper.
> >
> > Ken W7EKB