Dear sir, If you could spare a moment I would like to ask your attention to the following: A couple of years ago I came in possession of a 2280 Altec Incremental Power amplifier. The rack contains four amplifiers 2275, one driver 2252 and one driver 2250. As one channel on the 2252 is not functioning, the signal is routed through the 2250. Luckily, I obtained the technical instructions manual. My request, however: could you please shed some light on the high voltage opamps that were used on these card modules? I would be very glad with a circuit diagram of this part, if you have it. After so many years, it is not unlikely they will give up and I would like to be able to replace them. Also, I would like to know who made them for you. Thank you very much, best regards, David Orthel Amsterdam, Netherlands
