[Amps] 4CX1600B vs. GU84B

[Ian White, G3SEK]

Jeff Maass wrote:
>
>My club has, courtesy of Ten Tec,  a Ten Tec Titan II, which uses
>the Svetlana 4CX1600B. This tube has become expensive and
>scarce, and we are looking for an affordable spare 4CX1600B, or
>an affordable alternative.
>
>I've seen some references that identify the Svetlana GU84B as
>being the military analog, with a bit more dissipation rating, but
>needing more cooling air.
>

Some of these cross-references are vague to the point of being 
misleading (for example, some people call the GS35b a "Russian 8877", 
which it certainly isn't).

www.nd2x.net is the best source for data on Russian tubes, and it also 
features practical amplifiers. Data sheets are at:
http://www.nd2x.net/tube-1.html

The 4CX1600B data sheet is on the Svetlana site, at:
http://www.svetlana.com/graphics/products/pdf/4CX1600B.pdf

>Are they pin compatible?

The four grid pins look similar, but the central heater connection looks 
slightly different.

>Can the GU84B be used in a 4CX1600B
>amp without (or with) modifications?

"Maybe with" seems to be the answer.


-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
                            Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek