[Hallicrafters] Halli-Regenerative IF's vs True Q Multipliers.

[Philip B Atchley]

Hello Folks.
This is only partly related to Halli receivers, but I hope you will
indulge me.

I have a Lafayette HA-350 receiver coming that will be thoroughly
"chopped up" and converted to a single band longwave CW receiver for
Beacon chasing. (I won't go into the details but the physical/electrical
design of that set is particularly suited for the task). 

My question has more to do with the regenerative IF's often found in
Hallicrafters receivers.  The HA-350 has a 2.5kHz Mechanical filter for
selectivity with a 455kHz IF section.  I intend to leave that filter in
the circuit (1st IF stage) and install a Q Multiplier in the 2nd IF stage
for additional selectivity as I can't immediately afford to buy a 455kHz
CW filter.  

QUESTION:  How does the regen IF often found in cheaper Hallis such as
the S-120 compare in performace to a 'true' peaking Q Multiplier using a
single triode such as half of a 12AX7 etc?  By performance I mean
selectivity, stability etc, especially under changing AGC conditions.  

I see where in the S-120 the AGC is disabled when the regen is turned up.
 I prefer to keep the AGC engaged and have a separate AGC defeat switch. 
Since the HA-350 has a true product detector this should be no problem as
it's part of the oricinal design.  But will the REGEN IF change it's
Regen (Selectivity) with AGC action?  IF so I will probably go with a
separate Q mult tube as I'll have an empty tube socket. 

As this subject is probably of little interest to the group you might
reply direct to the email address below.  Thank you.

73 de Phil  KO6BB
Loving home provided for wayward Boatanchor Receivers
ko6bb at juno.com
Merced, Central California
37.18N  120.29W  CM97sh

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