Regulation really needed for SF

[mashaffer]

In a class A small signal source follower circuit the total current out of the power supply should, it seems, be fairly constant. So the question is... if the PS is well filtered is voltage regulation really necessary?

[h_a]

You gave already your own reply...if it's well filtered there's no reason to regulate it. Unless it's not well filtered enough for you

For ClassA source followers you can always use another follower as regulator (with Zener stack at gate), its output impedance is not that great, but sufficient for ClassA (see Nelson Pass Zen articles).

But for line-level stages a lot of cheap regulators are available, so why not use them if you're worried?

Have fun, Hannes

[AndrewT]

but the supply current is only near constant in the quiescent (no signal) state.
The supply currents are modulated by the signal and can vary from zero to double the quiescent current.