Start with having the source signal be at max or 95% of max. Then look into the gear’s manual and determine the output standard (home audio or pro) and ensure the entire signal chain is all using the same, some gear has a little toggle to bridge this gap as a small switch on the back. Sometimes labelled as (0 / -10) Toggling this alone may be all you need to do, as your signal source should be loud enough. You also want to start with a strong signal, so that the signal is much higher than the noise floor, if you amplify a weak signal you also amplify the noise floor so you want them to be very disparate. But to do exactly what you’re asking for, you could just have a series of pre-amps boosting the signal, but this isn’t the solution. Getting gear that either has the switch or is designed for the other class of gear in use is what you would want to procure. Second hand you could do so without spending a ton. Finding the switch or it’s equivalent is where to start, it may be on the mixers front panel hidden among all the knobs, but usually on the back Best of luck!
