[AMPS] 4-1000A Project

[Wynand van Wyk]

Hi William.

The transformer is one of two which was originally designed to be used in
the power supply of the low frequency transmitter of a submarine.

It is built to the highest military standards.  28 cm high and 18 cm wide.
You have to put your back into it to lift it.

It was build in the United Kingdom under contract for the NATO forces (cold
war period) so that why I call it a NATO transformer.

I used a classic 1950 power supply design with two smoothing chokes in the
negative line.

I am currently working on the power supply so if you want to see it I'll
take videocaptures and e-mail them to you.

The linear amp is a normal cathode driven (grounded grid) rated at 2
kilowatt PEP input.

The design is the U-8 as appeared in RADCOM.  What made me use it was the
fact that it was designed to function by interchanging the valves without
major circuit changes.  So one can use 3-1000Z, 4-1000A, 4-250, 4-400,
4-500, 813, 811A, 4CX150A, 4CX250B or 4CX300A tubes.

One just change the base plate and filament connections.

It will be my pleasure to share ideas.  I have just started with a new three
tube amp based on experiments I did with four 4-250's.  I could not tame
them on 10meters due to the capacitance of the four valves.  So now going to
try three.  Got some old Collins receiver casings past weekend at fleamarket
which I'll use for this amp.

73

Wynand.

PS We could try and have a sked.  With the current sun spots anything is
possible.  I have a log periodic that can work from 20 - 6 meters.


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