[Amps] Alpha 78

[Paul]

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 at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Carol Richards
> Sent: Saturday, August 25, 2012 1:07 PM
> To: amps at 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