Here is a quick test of a russian СГ2С (SG2S) 75V voltage valve regulator:
The CCS is a classic cascoded DN2540 MOSFET. A russian PIO capacitor is bypassing the regulator and the input impedance is the Pete Millet’s interface impedance. HT is a well regulated variable power supply.
Need to capture input of power supply at the CCS input
Edit: after measuring the power supply noise level and finding that is near -90dB, came up to the conclusion that the above noise level is the VR noise. Quite good for a simple (but effective) voltage regulator. Gary Pimms used this configuration many times on his designs…
Upon request from Vyacheslav, here is the noise analysis for different current points:
As you can see it’s very linear. There is a 4dB difference between 5mA and 40mA.
Also tested ripple attenuation using a poor-regulated HT power supply. Here are the interesting results:
- 62dB @50Hz
- 80dB @100Hz