08-14-2010, 05:05 PM
Perhaps National Union had a production line already set up for 41s, so those were cheaper than 6K6s produced by someone else. Or Philco wanted to give NU the business (Philco purchased a controlling interest in NU in 1940).
No factory made every tube; whichever one was geared up for a particular type at the time would make them for any other maker who needed them, with the other maker's logo.
No factory made every tube; whichever one was geared up for a particular type at the time would make them for any other maker who needed them, with the other maker's logo.
