The nominal supply voltage is +15V and -15V.
The AD797 op-amps are fed from 12V passive regulators and
there is also a 5V regulator for the HC-MOS IC's.
The RF amplifiers which run at about 0.12A each are fed directly from the input voltage through RC filters to avoid heating the regulators too much in case the unit is powered by a bit more than 15V.
The gate voltage for the RF amplifiers is stabilised with a zener diode and decoupled to source voltage.