From:	Stewart D Lyon [slyon@SPACEVECTOR.COM]
Sent:	Sunday, October 26, 1997 12:19 AM
To:	HEATH@LISTSERV.TEMPE.GOV
Subject:Soup Up the SB301 for $7

Soup up your SB301 for $7.00 or less.
If you are thinking of replacing the tubes in your -301,
the following may interest you. The tubes suggested will
provide a theoretical open-loop gain increase of 3 to 3.5.
I don't have the necessary test equipment to verify this 
but practically the receiver will be noticeably more sensitive. 

Position   Remarks     Type  Class       gm   Price**
V1(RFamp)  Orig.       6BZ6  SemiRemote  8K   ---
           Replacement 6GM6  SemiRemote  13K  $3.00

V6(1stIF)  Orig        6BA6  Remote      4.3K  ---
           Replacement 6AH6  Sharp       9K    $2.50
            or         6HR6  SemiRemote  8.5K  $4.00

Notes: Retune rf coils and T3 after replacement.
6AH6 provides smoother AGC action but tends to overload 
when used as a monitor of local CW xmtr.  
Do not change V7 type - circuit may oscillate!
BTW - The 6HR6 is a suitable replacement for the SB101 RFamp(V10) 
for the 6AU6 or 6HS6.
**Prices are from Vacuum Tubes Unlimited at
http://www.cinternet.net/~vactubes/index.html
73,  Stu W6CUX  (updated 7/17/00)