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Re:SA 750 question...help!

The input pad and EQ genera;lly give your flat input to the first active, while the interstage EQ does your output tilt, and the interstage pad would only vary if the engineer built the design to add an AGC/ACM, or a thermal with anticipated future plant extension where a low gain dual would be the eventual requirements to manage the new longer cascade. For instance, today, the amp is the last in cascade, so no agc or thermal is needed. So instead of having to change out amps, face plates etc, to add on that new apartment complex or neirboorhood that is in the process of signing on, you pad the interstage by the insertion loss of the thermal or AGC. Then when the plant extension occurs, you add on the plant and new actives (now a long enough cascade to require the need for control), trim out the jumper on the board and plug in the Thermal or AGC and change the interstage pad to zero. It allows the least customer affecting way to manage your plant.
There was a time when the high gain duals out performed their advertised outputs. It was determined that the interstage amp was the culprit. The answer given then, was to add a 1 or 2 pad at the interstage. This helped keep the CTB's and CSO's optimal.
As atated above, the output pads help you to maintain an even output level to each output leg. Problem we saw was that the tilt often varied between dual amp outputs by as much as 2.5 dB (typicvally 1 dB). We had three amp cascades so we usually didn't bother with such a trivial problem. we kept the output feeding another amp at the correct tilt, and if both fed an amp, one leg simply left a little hotter on the top end. Look closely at the block diagram from SA. It will help you follow the reasoning behind all this. You gotta love the simplicity of HFC.
This is CABL.com posting #39859. Tiny Link: cabl.co/mkw3
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