What you are seeing is perfectly correct. The valve heaters are in series, so there should be 10V across each heater. There is. Measure the voltage between pins 4 and 5 of the individual valves to prove the point. There's no voltage on V2 pin 4 with
respect to chassis, because that's your reference point. At least I assume it is?
I would suggest that the valves are in fact lighting up, but you can't see it. Try looking in the dark from various angles.
Quote:
Originally Posted by TimMills
Thank you both.
So I've learnt something already! The big central contact post in the centre of the valve socket is not as I mistakenly called it the 'centre tap' .... 
I can confirm Pin 9 the real tap is free from connection to anything on v1 and v2.
the valves are new, hand picked and matched and these 2 measure 32 ohms across pins 4&5. does that seem ok?
Can you give me any ideas please why would I not see a voltage at pin 4 of v2 if theres 10v going in on pin 5?
many thanks |