[Milsurplus] RAL Hum

[Hue Miller]

>RAL Owners:
>With the regeneration and rf gain all the way down, does your RAL have any 
>low residual 60 cycle hum?  Mine does, and I think it is induced into the 
>audio inductors from the heater wiring.  When I approach with the soldering 
>gun it increases enormously, and with dc on the heaters it disappears.  I 
>have Chinese 600 Ohm cans with a pretty good frequency response, and I 
>suspect with many headphones one couldn't hear it.
>
>TNX
>Richard, AA1P

I don't recall if i had posted this RAL factoid to  this list or only
GB, but there's a paragraph in a Navy maintenance book ( 900,103 ?? )
that mentions using preferred tubes in the RAL detector and/or RF
stages. Some brands of tubes had the heater wound in a different
pattern, which created more AC hum. That sound familiar? ( I'm not
making this up. )  If necessary, altho the book is not at my fingertips,
i can look up the item or again, or come to think of it, maybe just
locate the original post. -Hue Miller