I forgot to answer to this point: the reason why I asked is that 99.99% of the commercial amps are based on expensive 12AX7, and that mod could be applied to commercial amps by substituing the RC on the cathode with this system.
@Tubelab_com
I will give this circuit a try, reducing R5 until it is stable on the whole range of U2.
U2 will be a log pot, R5 will be most probably switchable to have two different loadlines.
Let's see if the voltage drop on plate voltage due to the current drawn by g2 during peaks will be euphonic.
I will give this circuit a try, reducing R5 until it is stable on the whole range of U2.
U2 will be a log pot, R5 will be most probably switchable to have two different loadlines.
Let's see if the voltage drop on plate voltage due to the current drawn by g2 during peaks will be euphonic.