[Hallicrafters] SX101A 50.75KC IF Amplifier

[Rodger]

Mark,

This is used to reduce the gain a little at this setting in order to 
avoid much higher gain at the 1 Khz. position as compared to the other 
selectivity positions.  Although the gain does vary a little between the 
various positions in a well aligned SX-101 the difference is fairly 
small.  This is used in other Halli receivers using the 50 Khz. IF 
including the SX-100 and SX-115 also.

Rodger WQ9E

Mark K3MSB wrote:
> If one looks at the schematics for the SX-101A, specifically the rear
> wafer (S5A Front) for the Selectivity switch, I notice that the
> Hallicrafters engineers switch in a 470 ohm resistor (R31) for the 1
> KHz selectivity setting only.    This adds an addition 470 ohms to
> cathode and grid of V6, for the 1 KHz setting only.
>
> I'm curious as to why they do this for just the 1 KHz setting only,
> and none of the others.
>
> Mark K3MSB
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