View Single Post
Old 11th Feb 2019, 10:59 pm   #36
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
Default Re: Capacitors for Trio 9R 59D

I worked it out

Sets like the 9R 59 were not designed with much care over low hum. It was assumed that it wouldn't degrade the readability of the limited bandwidth signals it was aimed at. You should expext some, but not so much as to be distracting. There are causes such as a limited amount of HT filtering, unbalanced heaters and also chassis currents from the mounting of the transformer core screws. There are several areas where you could make a series of small improvements.

David (GM4ZNX)
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now