[Amps] Henry 2K-3 PS Mod

[k7rdx]

There`s a good possibility of future problems because the plate transformer 
may not be rated for capacitor input filtering with the increased heating 
effect.Also,the hv supply couldn`t be nearly as regulated as with the tuned 
choke design Henry intended for their amps to be powered with.I don`t think 
plate tune spacing would be an issue for Henry as most things they built 
were with much over-kill..Jim,K7RDX..
----- Original Message ----- 
From: "Vic K2VCO" <vic at rakefet.com>
To: "Kevin LaHaie" <klahaie at centricata.com>; "Amps reflector" 
<amps at contesting.com>
Sent: Friday, March 21, 2008 1:15 PM
Subject: Re: [Amps] Henry 2K-3 PS Mod


> Kevin LaHaie wrote:
>> Hello
>>
>> I am planning to convert the stock P/S in my Henry 2K-3 to a purely
>> capacitor filter primarily to increase the HV, but in addition some way
>> that capacitor filters are better for SSB.   My other, newer Henry's (2K
>> Classic X and 3K Classic X Mark II) still use the choke filter design,
>> albeit with higher voltages, and never had a complaint!
>
>> 1. What changes to the biasing is necessary with the higher plate voltage
>
> According to the 3-500z data sheet
> <http://home.c2i.net/clank/ham/pa/3-500z.html>, class AB2 operation at
> 3000v requires a cathode voltage of +10v, with 3500v requiring +15v. The
> 2K3 schematic shows a 1N2808B zener in the cathode circuit, which is a
> 10v 50w part.
>
> I would keep a couple of other things in mind. Gain will be higher with
> higher plate voltage, so any tendency to instability will be magnified.
>
> I don't know what the plate spacing of the tuning capacitor is, but make
> sure it is enough for the increased voltage.
>
> I am not sure this is a good idea. Why do you want to do this?
>
> -- 
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
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