[ARC5] Receiver AC Power Supplies

[DSP3]

On 12/13/2014 10:09 AM, Mike Everette wrote:
> This is slightly off topic, but what you mentioned about the National 
> receivers reminds me of something I've observed with my NC-173.
>
> Using a metered Sencore variac/isolation transformer, I have seen a 
> "sweet spot" at about 105 to 107 volts AC input where the receiver 
> sensitivity peaks noticeably.  Above that voltage, even at 110 volts, 
> it falls off a bit.
>
> I haven't monitored any internal supply voltages to see what may be 
> happening; however, this is readily apparent just from listening to 
> the audio and incoming signals..
>
> 73
>
> Mike
> WA4DLF
>
> ------------------------------------------------------------------------
>
Tell you what Mike... I've not seen (but not tried, either) on the 
National but I have noticed that exact phenomena on ARC-5/274-N 
receivers at about 160v or so B+.  Curious???

Jeep - K3HVG