current requirements and power supplies

hi,

i currently have an older console (apsi 2000) with plenty of spare modules. i am thinking about taking some of the spares and making a small eight channel side car, or perhaps just a smaller eight channel mixer.

i am relatively new to building and modifying audio circuit (i?ve built the standard fuzz box kits etc), but do have a grasp of basic electronics theory.

anyhow i had a few questions i thought perhaps you folks could shed some light on.

first, how do i find out what the current requirements are for one of my modules?

second, i do have a schematic for the 24 channel board's power supply, i figure this would be a good place to start. however, i am wondering, could the smaller eight channel board run on that supply, or is a new power supply design necessary?

finally, i have read that increasing the operating voltage can lead to better audio (more head room as i understand it). how can i find out the limits of my modules components (is it as simple as checking the data sheets for the components) and figure out if i could/should try to beef up the voltage.

any insights or resources would be greaat

cheerio,
n

> could the smaller eight channel board run on that supply

Usually fine. May be relatively bulky for the chore.

> i have read that increasing the operating voltage can lead to better audio (more head room as i understand it). how can i find out the limits of my modules components (is it as simple as checking the data sheets for the components) and figure out if i could/should try to beef up the voltage.

You are not the first to think of this. I am sure if you study the parts used, you will find them working very close to some limiting rating already. People who design 24-channel mixers are usually not stupid enough to leave that trick undone.

OK, you may find +/-15V on +/-18V-rated parts. But that's barely 1.5dB different. And the +/-18V is supposed to be an absolute-max blow-up rating. It isn't wise to push it too closely. Now, a particular "+/-18V" part may work all day at +/-22V. In fact most will. But will it work for years? If you buy another lot next year, will they also beat their spec, or croak at 18.1V? I do have parts working at-rating for decades, but also other parts worked a little over their rating which die and have to be replaced every few years. In my headphone amp, this is tolerable. Multiple random burn-outs in a 24-ch board in a for-profit hourly-rates studio would be maddening.