[Amps] AL-1200 - MO Power??

[jeremy-ca]

For a net gain of close to nothing why bother? Nobody at the other end in a 
pileup or one on one will ever be able to tell the difference.

OTOH, Ive never had an AL-1200 thru here that couldnt easily do 2100-2200W 
with 100W drive.

Id suggest finding out whats wrong instead of defeating the design.

Carl
KM1H

----- Original Message ----- 
From: "Tony Brock-Fisher" <barockteer at aol.com>
To: <Amps at contesting.com>
Sent: Tuesday, May 20, 2008 4:00 PM
Subject: [Amps] AL-1200 - MO Power??


>I have had an AL-1200 for over a sunspot cycle. It has run well, but never 
>quite made the 'full boat' in terms of output. 1300 watts usually is what I 
>get. HV runs a tad low, around 3450 volts no load. I never drive it with 
>more the 100 watts (don't have a rig capable of more than that stock, and 
>no, I don't want to 'tweak' my Pro2 to make over 100 watts due to IMD 
>concerns).
>
> I am tempted to rewire the transformer primary to boost the HV. If I wire 
> it for 220 instead of 240, it would boost the HV to 3763V. 9.1% boost in 
> HV would give me a 19% increase in Po for 1547 watts out (naturally I 
> would dial back the Pro2 for legality).
>
> Yes, of course I have read the warning in the manual that says not to 
> rewire the primary for more than 3700 volts.
>
> I'm assuming that this warning is because the voltage rating of the string 
> of HV caps is only 3600 volts (8 x 450V). (Which seems like a pretty 
> marginal design in the first place).
>
> Supposin' I was to add another cap to the string, with the proper bleeder 
> resistor. Now the HV rating of the cap string would be 9 x 450 or 4050 
> volts. Total capacitance would go down from 210/8 (26.25 uFd) to 210/9 or 
> 23.3 uFd - not a huge deal.
>
> Does anyone see any problems with this idea? Any other concerns with 
> boosting the HV?
>
> -Tony, K1KP
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