[R-390] Ballast Tube Thread

[Bob Camp]

Hi

So unless I'm very confused ( as if I wouldn't fit in here if I was 
...) any patents that Amperite got on the ballast tubes had expired by 
the time the 390's went into production.

Again - what makes these little gems so darn expensive to manufacture?

	Enjoy

		Bob Camp
		KB8TQ


On Jul 5, 2004, at 8:53 PM, JamesMiller wrote:

> History of Amperite company began with Ballast Tubes
>
> 1922---Amperite Business Incorporated in New York City, NY by Samuel
> Ruttenberg-produced cartridge-type Automatic Adjusting Resistors( 
> ballast
> current-regulators) for tube-operated AC/DC radio sets
>
> 1930(circa)---Amperite Began making hermetically-sealed ballast 
> regulators
> in vacuum tube form with helium and hydrogen gas...
>
>
>
> http://www.amperite.com/DesktopDefault.aspx?tabid=10
>
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