Steady Progress

A project log for Tube Television Tennis

'Pong' made with Vacuum Tubes

256byteram256byteram 08/30/2014 at 09:590 Comments

Two of them now!

It's a little wonky but I haven't filtered the B+ supplies from the various sections. The two objects are completely independent but I wired the controls together to see how well they track each other. So far the left one (the original) is slower than the right one. This is because of small differences in the components used, including the tubes. 

I measured the current consumed on the B+ rail. At 82V it drew 44mA. That's about 3.6W. Remember however the voltage regulator dissipates power and so do the filaments on the tubes. There's about 100V across the regulation tube so it's throwing out  4.4W and getting quite hot. In fact the tube I was using (a 6GV8 triode/pentode) was getting a little too hot so I wired in a separate pentode (6CM5, a common Australian horizontal output tube) in place of it, keeping the triode in circuit.

The filaments draw 3.75A, excluding the regulator filaments which have their own supply. The voltage is 8.2V, higher than what I'd like it to be. The transformer has taps on it for different line voltages. That makes the power consumed by the filaments 30.75W, and the overall consumption about 38.75W. Given the television chassis the mains transformer was taken out of would have taken more than 100W, I'm quietly confident the transformer won't let out any magic smoke in a hurry.