Ampdog
R.I.P. 23 June 2022
I have just 'dissected' an ECL82, and found a strange pentode construction.
Firstly, though the valve is normally called a triode-pentode, Russian types (e.g. Winged C) use a beam type pentode (2 grids), whereas others (Mullard) use the classic 3 grid pentode construction. Such a variation is rare though not unique. E.g. there are 6CA7s (EL34 equivalent) also using the beam construction, though most 6CA7s are pentodes. I have even read about a beam (marked) EL34, but only once.
What is strange in my example of the ECL82 though is that the screen grid uses only every second grid wire turn, i.e. half as many grid wires as the G1. The grids are still aligned as per beam type construction.
Apart from a singe mention, Google renders no information about this. Anybody here who can comment?
Firstly, though the valve is normally called a triode-pentode, Russian types (e.g. Winged C) use a beam type pentode (2 grids), whereas others (Mullard) use the classic 3 grid pentode construction. Such a variation is rare though not unique. E.g. there are 6CA7s (EL34 equivalent) also using the beam construction, though most 6CA7s are pentodes. I have even read about a beam (marked) EL34, but only once.
What is strange in my example of the ECL82 though is that the screen grid uses only every second grid wire turn, i.e. half as many grid wires as the G1. The grids are still aligned as per beam type construction.
Apart from a singe mention, Google renders no information about this. Anybody here who can comment?
