SB101 with 6HS6 RFAmpl.

[Stewart D Lyon]

Hi gang,
Does anyone have info on the mod that was made to the SB101 that replaces
the 6AU6 in the RF amplifier (V10) with a 6HS6 ?  My SB101 has the mod that
was done by me about 20 yrs ago and I have lost all info on it.  I think it
was probably a change in screen and cathode resistors but Chuck Penson
mentions added caps (?) in his book.

I would like to start a technical debate on the design of the SB101 & 301.
Why are the RF and IF tubes in the SB-301 remote-cutoff pentodes whereas in
the SB-100/2/3 sharp-cutoff pentodes are used??  Conventional wisdom is that
remote-cutoff tubes are desired for a stage that has AGC control.  I went
through the other Chuck's book on Hallicrafters and all their last designs
also used sharp-cutoff pentodes in the RF and IF amplifiers - same as the
101.  What's going on here? Is my RCA tube manual (my only source of tube
circuit design) wrong?  Of the 400+ subscribers to this forum their must be
enough experts to either start a healthy (and friendly) debate or enlighten
us unwashed.

73,  Stu - W6CUX

S. D. Lyon, Space Vector Corp.
email: slyon at spacevector.com
Phone: (818)734-2610 or (818)886-6500
FAX:   (818)886-3947