[Hallicrafters] Bumblee Caps

[hallicrafterssr2000 at k9axn.com]

Questions regarding the history of these components.

1.  Who manufactured the Bumble bee, Black beauty, Black cat, etc
     capacitors?

2.  Did General instruments ever make paper caps and when did they
     start building Polyester caps?

3.  Does anyone have a good Bumble Bee cap in their possession?

The SX-100 and other early 50Kc I.F. systems used 10% non–inductive (High quality?)Bumble Bee caps on the band width switch.  I have not found a single one of those caps that were within measureable tolerance due to leakage.  

Note that the SX-117, HT-44, SR-150, and later radios used General instruments non-inductive Polyester, not paper caps, that are as good today as when they were built.  They look like the old paper caps but are not --- they also have the General instruments logo.

One of the most common mistakes when restoring the later radios is to replace all of the paper caps with ceramic disc caps.  Bad move, they are Polyester and stable, not paper, whereas the high K ceramic are unstable, unpredictable and totally inappropriate for these circuit designs.

When replacing the caps on the 50Kc band width switch, use Polypropylene or Polyethylene film not ceramic disc caps.  BTW, all of the Hallicrafters radios used non-inductive caps in the 50Kc bandwidth selection circuits. 

Kindest regards Jim K9AXN