[ARC5] Potentiometer value needed

[Brian Clarke]

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