ATC SEMITEC DIODE, CURRENT REGULATOR

[Celsius]

I was looking a CCS for low current tubes and I found this diode regulator, who have experience with this type of regulator, will be noise...

Is a zenner diode with fix current.

 

[zigzagflux]

They do function, but have voltage limits that often preclude their use in tube circuits. They also don't perform nearly as well as the 10M45 or IXYS parts. LM334 is a better option than just a current limiting diode.

 

[Celsius]

They do function, but have voltage limits that often preclude their use in tube circuits. They also don't perform nearly as well as the 10M45 or IXYS parts. LM334 is a better option than just a current limiting diode.

But for cathode biasing is under parameters. 1v to 50v or 1v to 100v depends of the series.

 

[zigzagflux]

But the impedance of the diode is probably one or two orders of magnitude lower than a LM334, LM317, or other similar device. This is not ideal. Also the capacitance of the diode is likely much higher than the same, also not ideal.

If you want to try it go right ahead. Just saying the cost difference is minuscule for a significant performance increase.

 

[dsavitsk]

CRDs are basically just JFETs with the gate tied to the source and sorted for Idss. Impedance isn't terrible necessarily, but they are generally expensive, and they can be bettered for less money. They do save space and eliminate the need for external components, however.

 

[kevinkr]

I've not had very good results with CRDs in any sort of AC amplifier circuit, there is generally a lot of capacitance across the terminals and the tolerance on current regulation is broad.
They can also be quite noisy. (They might work ok in a cathode follower circuit, but I would hesitate to use them anywhere else.)

A cheap cascode of DN2540 betters one of these CRD in all respects and may not cost much more.

Maybe SY will weigh in here at some point, he is well versed in the advantages of a slightly more sophisticated current regulator.