I'm looking for information on a couple obscure vintage Japanese McAudi 2520/990 opamps. Does anyone have any information from these? There is basically no information online, but what I pieced together is that it's either a API 2520 clone or Jensen 990 clone. Possibly to have been used in a Sony MXP recording console I'm guessing or standalone microphone preamps. I have no idea what the voltage is for them. Is there any way to find it if this is 16v or 24v?
