[ARC5] [BoatAnchors] Receiver Tube Substitution

[Richard Knoppow]

     Mixers and converter stages don't really work well with AVC.
    For those who wonder a mixer works with a separate oscillator while 
a converter does both.
    I've seen a couple of articles about the 6K8 from about the time it 
was introduced, supposed to be a great improvement over previous 
converter/mixer tubes.

On 12/18/2016 4:38 PM, Scott Robinson wrote:
> On 12/18/16 1:58 PM, Richard Knoppow via BoatAnchors wrote:
>>    The BC-779 and other Super Pro receivers used a 6K8 mixer, even
>> noisier than the 6SA7. It was about the best of a bad lot at the time.
>
> ...and Scott comments:
>
> The real bad apple is the 6A8, in which the AVC pulls the LO like a
> fiend: at 18 MHz, one good wood radio (GE G-106, for those interested)
> pulled 20 kHz due to AVC action. By only changing out the 6A8 for a 6K8,
> which was designed to fix this problem, the pulling was reduced to 1
> kHz, a major improvement.
>
> I have not measured the sensitivity of this receiver, so I don't know if
> it was affected by this change. It does have a 6K7 RF amp.
>
> Peace,
>
> Scott
>
>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL