Steve Thompson wrote:
> David Lisney wrote:
>
>>Hi, my own little tetrode amplifier uses a conduction cooled version of the
>>4CX250, the CCS1, my screen supply is merely a pair of BU208 television
>>transistors, one configured as a constant current source, the other as a
>>shunt regulator. If the screen of the valve "tries to hard" to climb towards
>>the anode voltage a thyristor clamps it down to chassis/cathode potential.
>
> snip
>
>>Possibly a further consideration with these valves is to protect the bases,
>>I don't know just how much they can stand voltage wise on the screen bypass
>>capacitors... maybe someone else can comment?
>
> I've just put a couple of bases on hipot. One is a Johnson
> 124-110, the other is by AEI (quite common at UK rallies).
> Both look very similar to the SK600 family.
>
> On both, discernable current (<1uA) starts to flow at a bit
> over 2kV.
>
> Steve
As far as I am aware (the data sheets are on my web site) the CCS1 need
a BeO base. I guess you could dispense with that if you used a small fan
to keep the base seals cool, but if you want to run it silent, I think
the base needs to be a special one.
I have a base and the screen decopuling capacitor is a sepparate unit -
another of my many projects that I hope to finish one day.
--
David Kirkby,
G8WRB
Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/
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