If the two controls are for the two channels it is a damn nuisance. When stereo was first introduced I, and some others, used two mono preamps, because there weren't any stereo ones. I stacked two Heathkit preamps, installed a stereo volume control in one of them and ran the signal from the other preamp up and back.
Some preamps (but I haven't seen any lately) had, for each channel, volume controls at the input and at the output. This lets you optimize the signal level going through the circuitry. My electronic crossover, Ashly, has this feature today, and I use it to allow a high signal level through the digital circuits of my Behringer DEQ2496 equalizers without overloading the crossover or power amps.
Some preamps (but I haven't seen any lately) had, for each channel, volume controls at the input and at the output. This lets you optimize the signal level going through the circuitry. My electronic crossover, Ashly, has this feature today, and I use it to allow a high signal level through the digital circuits of my Behringer DEQ2496 equalizers without overloading the crossover or power amps.