COSSOR 77 2P valve - UK Vintage Radio Repair and Restoration Discussion Forum

jonnybear · 6th Jan 2012, 5:38 pm

Reading an old post I noticed several suggestions as a reasonable replacement for the 2p 2 volt valve, some suggested 6.3 volt valves with separate heater transformer, and there were 4 volt alternatives with 2 amp heaters putting 75% increase on the 4 volt heater winding.

Believe it or not the valve I used to get the Cossor 77 up and running was a EL81 (early line output valve) which has almost identical characteristics to the 2p, wiring it as a triode and wiring the 4 volt heater supply in series with the 2 volt heater windings that gave me the 6 volt heater supply for the valve, I know it is not 6.3 volt EL81s heater but it works beautifully.

6th Jan 2012, 5:38 pm	#1
jonnybear Octode Join Date: Nov 2010 Location: Cullompton, Devon, UK. Posts: 1,435	COSSOR 77 2P valve Reading an old post I noticed several suggestions as a reasonable replacement for the 2p 2 volt valve, some suggested 6.3 volt valves with separate heater transformer, and there were 4 volt alternatives with 2 amp heaters putting 75% increase on the 4 volt heater winding. Believe it or not the valve I used to get the Cossor 77 up and running was a EL81 (early line output valve) which has almost identical characteristics to the 2p, wiring it as a triode and wiring the 4 volt heater supply in series with the 2 volt heater windings that gave me the 6 volt heater supply for the valve, I know it is not 6.3 volt EL81s heater but it works beautifully.