Upgrade SB-301

[Stu Lyon]

Been there, done that. Found that a 6HS6 is a better choice for the 2nd
mixer. I tried a 6AH6 in the 1st mixer. The best thing you can do for a
SB-301 is replace the 6BZ6 in the RFAmp with a 6GM6. Using a figure-of-merit
of gm/Rn, the 6GM6 is about 2.5 times "better" than a 6BZ6.

I tried the following line-up in my SB-301:
6GM6 - RfAmp: 6AH6 - 1st mix.: 6HS6 - 2nd mix.: 6HR6 - 1st IF. (6AU6 - 2nd
IF).
All this was mostly an exercise in how hot I could make the set without
turning it into a big oscillator. The set was really "hot" but all receiver
theory tells us that the sensitivity comes from the 1st stage. What we need
here is something with reasonable gain and low noise - and that's what the
6GM6 does. All the rest just makes the S-meter read higher.

After all this tube switching, I also ended up with some very hot fingers.

73, Stu W6CUX
Winnetka, CA
ARRL Life Member

Ed, what was all that garbage hung onto the back of your message?? Something
about "public key block". Hope you didn't give me a virus. Stu


----- Original Message -----
From: "Ed Gardner" <egardner at TWCNY.RR.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Thursday, September 14, 2000 6:08 PM
Subject: Re: SB-101 Factory Mod to Upgrade Receiver


> Anyone know if this mod will work on the SB-301? Its got 6AU6's in the
> first and second mixers.
>
> Ed

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