[Amps] 3-1000Z - Filament Voltage

[Bob Maser]

You can't hurt a 3-1000Z unless you roll it off a desktop onto a concrete 
floor.  Just set the filament voltage to 7.5 and go with it.  I ran a pair 
of these tubes back in the 60's and 70's and never even checked the filament 
voltages.  Heck, they will even run for a time w/o a blower.

Bob W6TR
----- Original Message ----- 
From: "rob" <VE6TR at telus.net>
To: <amps at contesting.com>
Sent: Tuesday, May 09, 2006 10:22 PM
Subject: [Amps] 3-1000Z - Filament Voltage


> Greetings,
>
> I have a Harris RF-104 with a 3-1000Z tube.  I have several questions 
> regarding the filament voltage.
>
> The Eimac spec. sheet that I have lists the filament voltage as a nominal 
> value of 7.5 volts with no min or max values
> shown (unlike the 3-500Z spec. sheet which has min/max values).  The 
> Harris RF-104 that houses and powers the
> tube has a spec. of 7.8 volts.  As I've had to adjust the filament 
> transformer taps to achieve 7.8 volts (due to different
> line voltage here), I was wondering if:
>
> 1.  There a preferred voltage to run the filament at?
>
> 2.  There a loss of tube life running the filament voltage too low or 
> high?
>
> 3.   There a practical tolerance for the filament voltage?
>
> Any information would be appreciated.
>
> ... 73
>
> Rob Brennen VE6TR
>
>
>
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