[Amps] Svetlana 572B and FL-2100Z

[Alek Petkovic]

A friend of mine Has recently bought a FL-2100Z and it is fitted with 
Svetlana 572B tubes.

He has had a couple of bangs so far on 20m resulting in the loss of the 22 
Ohm parasitic suppressor resistors.

Also, a previous owner has put 33 Ohm wire wound resistors in the grid 
circuit. The originals were of course non inductive resistors which are 
very hard to source here in Australia.

I am sending him some new 33 Ohm resistors and some nichrome wire to make 
up some new suppressors plus a glitch resistor.

I am also sending him some new Cetron tubes and have advised him to get rid 
of the Svetlanas and put some extra resistance in the filament line to 
reduce the voltage to a safer value.

Has anybody had any experience with Svetlana 572B tubes? I was under the 
impression that they spelled trouble in hf amplifiers. Is this a fact?

73, Alek
vk6APK


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