Hi all,
Just got a pair of these rather unusual (and supposedly rare) VR tubes.
They're marked "SR2B CERBERUS" ,the later being the manufacturer.
What makes them unusual is the double anode feature (see the footnote 1 in the datasheet attached).
I'd like to put them on work,say as a reference VR in a regulated HV PS but I'm not sure how to wire the anode(s).
Any hints?
TIA!
Just got a pair of these rather unusual (and supposedly rare) VR tubes.
They're marked "SR2B CERBERUS" ,the later being the manufacturer.
What makes them unusual is the double anode feature (see the footnote 1 in the datasheet attached).
I'd like to put them on work,say as a reference VR in a regulated HV PS but I'm not sure how to wire the anode(s).
Any hints?
TIA!
As a reference VR in a regulated HV PS follow the data under A in the datasheet. Use only one of the anodes. You should calculate R so that about 5 mA flows through the SR2B. In the datasheet they take V = 135 V as example and so come to R = 10K. If the supply voltage to the VR is higher than 135 V, R must be higher too.
Depending on the circuit, the current of the voltage amplifer tube also flows through the VR so R should be corrected for that.
Depending on the circuit, the current of the voltage amplifer tube also flows through the VR so R should be corrected for that.
Thanks EL504! 
One more thing:not sure what the R1 (and R2,for that matter!) stands for.
Can you explain?Or,even better,relate these two resistances (resistors) to a specific schematic diagram?
Thanks!
One more thing:not sure what the R1 (and R2,for that matter!) stands for.
Can you explain?Or,even better,relate these two resistances (resistors) to a specific schematic diagram?
Thanks!
I am not sure about the meaning of R2 = 0,2M.
Take a look at the schematic of a headphones amplifier i made: "Aikido" headphones amp with ECC40 and E182CC
Suppose i wanted to use a SR2B instead of the 0B2. In this schematic there is no other current going trough the 0B2 than the current going through the 2 x 7K5 resistors (= 15K = R1).
The datasheet for the SR2B reccomends 5 mA if used as a reference VR. The voltage of the power supply (from which the VR is fed) is meant to be 300 V. The stabilized voltage of the SR2B = 86 V. So R1 has to drop 300 - 86 = 214 V at 5 mA. R = V/I = 214/0,005 = 42K8. So you can take R1 = 39K.
In this example i did not pay attention to the fact that the reference voltage of the 0B2 = 107 V while that of the SR2B = 86 V. Look at the example like you wanted the reference voltage to be 86 V. Beside that, i think the power supply of my amplifier would also work fine with a reference voltage of 86 V.
Take a look at the schematic of a headphones amplifier i made: "Aikido" headphones amp with ECC40 and E182CC
Suppose i wanted to use a SR2B instead of the 0B2. In this schematic there is no other current going trough the 0B2 than the current going through the 2 x 7K5 resistors (= 15K = R1).
The datasheet for the SR2B reccomends 5 mA if used as a reference VR. The voltage of the power supply (from which the VR is fed) is meant to be 300 V. The stabilized voltage of the SR2B = 86 V. So R1 has to drop 300 - 86 = 214 V at 5 mA. R = V/I = 214/0,005 = 42K8. So you can take R1 = 39K.
In this example i did not pay attention to the fact that the reference voltage of the 0B2 = 107 V while that of the SR2B = 86 V. Look at the example like you wanted the reference voltage to be 86 V. Beside that, i think the power supply of my amplifier would also work fine with a reference voltage of 86 V.