[R-390] Ballast Tubes - Resistor

[Rbethman]

Group,

    I've pulled the resistor in my R-390A.

    It is a Sprague "KOOLOHM", 50 ohm 10W.

    It goes between pins 2 and 7.

    Mr. Camp - what say you?

Bob - N0DGN

David C. Hallam wrote:

>According to my RCA Tube Manual a 6BA6 is rated 6.3 V at 300 mA, so 2 tubes
>in series 12.6 V at 600 mA.  Supply voltage is 25.2 V so you want to drop
>12.6 V with 600 mA of current
>
>12.6/0.6 = 21 ohms
>
>21x0.36 = 7.6 watts
>
>A resistor ( 21 ohms at 10 watts would seem right
>
>David C. Hallam
>KC2JD
>
>
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>

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