Anyone have experience of using Constant Current Source ? LND150/J113/1N5297

[frequencycentral]

Anyone have experience of using constant current source ? Specifically in place of an anode resistor in tube circuits?

I've been looking at this: http://headwize.com/projects/cavalli2_prj.php

"The tube is loaded with a constant current source (CCS) for two reasons:

1. The resulting non-linear performance associated with low voltage operation is partially offset by the high dynamic impedance of the CCS
2. A CCS has a much better PSRR than a simple resistor making it possible to have more ripple in the B+ and, therefore, simplifying the B+ PS."

There seem to be a number of options:

- LND150 MOSFET

- J113 JFET

- 1N5297 current regulator (CR) diodes

I guess it's obvious that I'm hoping to get more gain from a tube stage at low voltage.