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 is much more sensitive with these tubes.

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