DHT tubes compatible with 5 Volt, 4 Volt and 2.5 Volt heater voltage?

[Nuforce]

Does anyone know of a chart etc that shows all DHT tubes compatible with 5,4 & 2.5v? I am aware of the obvious ones like 300B, 2A4, 45 but what other DHT tubes can accept these voltages?

Thanks

 

[cjfrbw]

6b4 are 2a3 with octal base and 6.3v filament. They work fine at 5v, too, as long as they are fairly new. They are usually Svetlanas/Sylvanias, and very well built, so they can operate at 300v anode w/o problem to put out about 4 watts. An octal to 4 pin adaptor will allow them to plug into the 4 pin sockets. They sound great, quite comparable to high quality 2A3 or 300b without the 'status audiophile' cost inflation.