>
>Hello,
> I just acquired a Heathkit SB-220 Amplifier that uses a pair of 3-500Z
>Tubes. The specification and manual do not indicate what the maximum
>allowable Plate
// 400mA per tube
>and Grid
// Grid dissipation is 20w max. This equates to c. 220mA per tube.
However, if you tune for max RF out with max. drive applied, all will be
well. Since the 220's power supply is not adequate for AØ, tuning up
with 50wpm dits is preferable.
> Current can be. The specification from Eimac
>indicates 500 ma per tube
// unsliced bologna.
>which would be a total of 1 amp for a pair.What
>can I run without damaging the amplifier ( or what should i avoid is the
>real question ??)
>
// 300mA indicated is c. 800mA on voice peaks.
cheers
>
There's an article on circuit improverments for the SB-220 in the
November-December, 1990 *QST*. This article is also on my Web site.
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
end
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