FutureT-at-aol-dot-com wrote on Tue Jan 21 23:10:35 1997:
>>I am not at all familiar with the nomenclature ECC803S, but I was
>>able to look up a type 803 transmitting tube in the RCA databook.
>>Although this tube is a pentode, at 2000 volt plate rating and 125
>> watt plate dissipation it is a heck of a lot of tube for $15,
>>assuming of course that what you have found is truly an 803. If it
>>is, I'd get one and try it. Tie all three grids together and pretend
>> it is a triode, might work. The filament on the 803 is 10 volts at 5
>> amps. The tube has a plate cap and a giant 5 pin base (same as a
>>4-125A/4D21, with a straight sided diameter of 2-9/16" and an overall
>>length of 9-1/4".
>I also do not know if the ECC803S is the same tube as an 803. I used an 803
>in a tube coil, (found 3 of them at hamfest for $3 each), I connected a 15k
>resistor from the high voltage supply to the screen grid, and a 45k resistor
>from the screen grid to the suppressor grid, the coil gave a 5 to 6" spark.
> By the way, an 845 tube gave a 7" spark, and a 304TL tube gave a 10" spark
>in the same tube coil, which happened to be powered by a microwave oven
ECC803S is a typical European valve type number. E = 6.3 V heater,
CC = Twin Triode, 8 = noval base, 03 = Serial number , S = Special (?).
ECC803S is replaceable by 12AX7S or 7025, which has a 1W plate dissipation.
Good for small signal audio, no good for tube Tesla coil driver.