Yeppers - older design for the purpose of being able to even use FM too...
The Modulator delivers phase modulation too - Deviation is thru RV5
So even though full collector voltage - the CARRIER power is set up to be limited.
AM side is set for 1/2 - while FM mode is uses the AM "carrier" but it is deviation-driven - no envelope.
So you're limited to bipolar at the moment - but MOSFET can work - just carrier power is not present in which the little EKL devices can work independently - they will need a "trickle" or tickle-voltage to raise the MOSFET drive power.
A simple 10K or even 5K pot can do this...you'll need 3 parts - two to buffer and one to adjust...
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This is from a filtered power source anywhere that is convenient - this supplies the trickle voltage.
1K buffer input keeps the supply side of this feeder from sagging - the 1K output keeps the EKL from interacting too heavily with this sourcing of power to just raise the drive voltage - 1K acts similar to a high impedance
You can try using a simpler divider - but how many parts are you going to make as possible combinations?
This gets you started and lets you experiment and adjust voltage to acheive certain effects of power and how much of the power can be developed before the audio and signal present - is pinched off.
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Once you know the value - you can measure across to find a TOTAL resistance needed and make the divider permanent once you have set the right voltage. But Total amount to use - needs are thru a divider, not just one big resistor...
So you will still need two resistors - to find that value of both you measure from the aspect of the EKL requiring this power.
So measure from the output Buffer Resistor - to Source Buffer Resistor the pot has given you a resistor value of it's own divider two fixed with one wiper - to obtain this "ground" and "source" values thru itself.
We should have done this right from the start - it can save you time later when knowing you didn't have enough carrier power to make the EKL work as a stand alone - this gets you variable power.
