[Drake] L-4B

[fkamp at comcast.net]

joe sloss wrote:
> 
> Is anyone aware of any articles or mods that will allow the 3-500Z filaments to reach operating temperature before the tube is hit with B+ ,  ie a delayed B+ arrangement.
> 

I used to have  high respect for the L-4B.  Upon hearing this
disclosure, I see that that respect may have been missplaced.

Even my lowly, homebrew set of 4-400s has this feature.  Makes you
wonder why Drake would have been immune to the need to design something
that could protect itself.

The 'how to do it' is close to trivial.  The 'why they did not consider
that' is another matter entirely.

I can offer 'how-tos' off line if you are interested.

Regards,
Frank Kamp
K5DKZ