Not wanting to go at too many tangents, there is the Mullard EL35, which making reference to The Valve Museum
www.r-type.org the Mullard EL35 is down as an equivalent of the 6L6 and looking at the data I personally feel the EL35 was Mullard’s ‘pentode’ take on the 6L6.
A couple of the EL35’s I have here in the toy box have a mesh anode (as per the pictures on the Valve Museum site, so you can clearly see the grid structure and its defiantly a pentode.
http://www.r-type.org/exhib/aaa1624.htm
I recently tried a pair of the EL35’s from the toy box in the fixed bias 25-Watt guitar amplifier project. They worked OK, but lacked the power I expected.
Sadly, the valves I have here, all of which came with some other stuff many moons ago, really aren’t the best selection where two were duff another two were OK and ‘just usable’ with low emission (these are the pair I tried in the amplifier), however, the fifth is very good, however sadly, I have nothing useable to match with – If I saw another good EL35 at a sensible price I could revisit the EL35, but definitely not at the silly prices
I’m seeing on the internet sales sites!
Terry