[QUOTE=Apparently, the Prowler has active EQ while the Valveking 112 has passive EQ. Is there a way to convert the Prowler's tone stack into the Valveking's?
Moreover, there is another difference near the end of the preamp. The difference is that the Prowler includes 4 extra diodes (all 1N4148). What are these diodes for?QUOTE]
I would not say the Prowler is "active".
That usually includes a transistor or an opamp in the circuit.
The whole preamp send circuit is different on the Prowler.
Not just the diodes.
The circuit is a buffer.
It is active.
The diodes are for clamping the input & output of the transistor.
It helps with noise imunity.