Grid Mount Assembly
GS-31 & GS-35 Coaxial Triodes

The GS31b and GS-35b triodes are two of a family of Russian tubes that have recently become available to the amateur constructor. They are an excellent, low cost component around which to design and build high power linear amplifiers. The GS1b is identical in most respects to the GS31b and can be substituted with out problems.

Several people have published circuits using these tubes, and a few amplifiers have already been built in the UK which are giving good results. The data provided here is graciously provided by G4HBA who is intending to build and present amplifiers on his web site as he develops it.

There have been comments which advocate securing this tube to the chassis directly with the grid connection by one means or another. It is important to realise that a substantial amount of heat is dissipated via the grid connection, and also for optimum rf performance a very good electrical connection to ground (chassis) is needed. The only way to satisfy both of these criterea is to make a grid mounting ring, or block into which the tube seats firmly. This method of mounting is electrically and mechanically sound and works exceedingly well.

Drawings and photographs of the grid ring designed and manufactured by G4HBA are shown here. Several have been manufactured and comments received have all been good. Skill in using a lathe, or access to some one who can use a lathe is required. I am fortunate to work for a precision metalwork engineering company with well equiped workshops. The material used is alluminium plate 1 inch thick, and brass sheet about 1 mm thick. The drawings and photographs give a good idea of what is involved.

  • Drawing & photos of mounting block of the G4HBA grid ring mount assembly

  • Drawing & photos of clamp ring of the G4HBA grid ring mount assembly

  • Mount by DL6YEH (scroll down)

  • Grid Ring mount by OZ1GOK (SK) - OZ1DPR can help with this mount:

G4HBA Grid Ring Mount parts & GS-31b