I am considering upgrading op amps in my lm 502 dac. However the dac has two selectabel outputs: transistor and tube. Does any one know if the op amps are in the commen path of the two outputs ore only the transistor output?
If you don't have a schematic for the unit, sometimes its possible look at the part numbers on all the chips, download datasheets for the parts so you know how the pins are mapped, then follow PCB traces around to figure out the interconnections between components. If you can sketch up a schematic at least of the part of the circuitry you are interested in, then the answer to your question should become clear. Sorry, don't have a better idea. However, I have sketched up schematics from following PCB traces before. Sometimes it can be practical to do, other times not.
