I use this in conjunction with my XR Oscillator board for the modulating signal. This AM modulation board can get me up to 1.8MHz using 5.6k 10 turn pot with about 75pF.

Juggle the Level, Wave Shape and AM Biasing controls and you can get a nice symmetrical AM modulation. I put a 1k on the audio oscillator output to control the modulation depth.

The voltage regulator to set a stable voltage across the modulation bias. Running the modulating IC on the same 15V provides plenty of output signal. Since its only low frequencies I'm putting the AM output through another 1k pot for output level. A 600ohm resistor on the wiper to avoid basic impedance to NOT hit 0.

Run a cheap frequency meter across the output.