shunt regulator using VR tubes (with ccs like g pimm) and circuit load

[jarthel]

for example: I have set the CCS to output 60mA. But when I measure the load being used by the circuit, it is only 50mA.

questions:
1. What happens to the extra 10mA? Does it pass through the VR tubes going to ground?

2. would the result be the same if the VR tube has been replace by some other shunting tube regulator like those found in various places/guides such as sbench and tubecad?

thank you for the help.

 

[Gluca]

1. yes
2. dunno what sbench used, but I guess it is the same
3. lovely VRs, bypass them with a high quality film/teflon cap (max 0.1uF)
4. you want to pass 10ma or more thorough the VRs (less than 30ma depending on the type)

Ciao


EDIT: added point 4

 

[Sheldon]

2. would the result be the same if the VR tube has been replace by some other shunting tube regulator like those found in various places/guides such as sbench and tubecad?

They all work on the same principle. Upstream components either provide a constant current or use a current limiting resistor, and the regulator part controls the voltage to the amp by partitioning that current between the amplifier or ground. So they all operate with some current in excess of what the amplifier needs. The excess is shunted to ground. The extra stuff in Steve's circuits either increases the current capability of the regulator, or lowers the impedence, or improves the line regulation, or all three - at the cost of added complexity.

Sheldon