I had an Alpha 76CA with the same Hypersil transformer that is used on the
78.
I installed that transformer in my Alpha 76A equipped with a pair of
3CX800A7's and an auxiliary cooling fan, and about 3 hours into an RTTY
contest running 1.5Kw the transformer started to smell like it was very hot.
I dropped down to 1Kw output and no further problems.
FWIW, I found that the stock 76A transformer is better than the Alpha
Hypersil or a Peter Dahl Hypersil. This conclusion based on a higher plate
voltage while running 1.5Kw output.
My 76A requires about 105 watts drive for 1.5Kw output.
de Paul, W8AEF
ZF2JI/ZF2TA FO8DX/FO8PLA 8Q7AA XZ0A VU7RG/VU3PYM TX5C A52PP
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Carol Richards
> Sent: Saturday, August 25, 2012 1:07 PM
> To: amps@contesting.com
> Subject: [Amps] Alpha 78
>
> I am using an alpha 78 with a pair of 3cx800A's instead of the hard to
> get and afford 8874's. I get about 1200w output on cw. Not bad since
> the power supply only provides 2000V and I am only able to drive it with
> 100w.. My question is when I operate RTTY is it still safe to run the
> alpha at max output or should I cut back on the drive...This is especially
> important if I plan to operate a RTTY contest.
>
>
> Thanks,,,,
>
>
> Carol
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