What do you think about idea of using dedicated voltage regulator on each preamp board which would be fed from LM317/337 output?
This way I could go with higher voltage from the first regulator ( lets say +-34V ) so I could power also those JLMs high voltage op-amps. The challenge in this is to determin proper secondary voltage since everything is getting to close to the LM317 max input ( which is 40V, I think ).
PS would power 8 preamps that use only single-end +24V supply and consume around 110mA per preamp, in total 880mA. It would also power 8 various op-amp based pres which consume max. 60mA per rail. That would load my positive rail by 880mA + 480mA = 1.4A ( I did not calculated phantom here because it has its own winding which would be able to deliver 500mA ).
Negative rail will be loaded with 480mA in full working scenario.
If current per positive rail is max 1.4A and I have 39V at the input of the first regulator , it means I would have 5V of voltage drop * 1.4A which would give 7W of heat for the first positive regulator to dissipate. Pres that need either single end +24V or dual rails would have dedicated regulator on board locally, which would need to drop voltage by 10V. Since it is only feeding one pre that is consuming around 110mA of current, heat that local regulator needs to dissipate is 1.1W ( for single end ) and 0.6W per rail for dual-end.
Are my numbers approximately correct and what do you think about this kind of construction ?
Best
Robert