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Thread Starter 
Hey, guys. I just got a deal on two mono "commercial power amplifiers," circa 1981. They use the old screw-secured output connectors, which is fine. But I confess that this model has options that I am not confident I know how to correctly set-up. I'm apprehensive that I'm going to damage an amp or a speaker by fooling around with them.

Each amplifier seems to have three pairs of screw-secured wire outputs. From
left to right, they are **HI - LO||COM - + (over AMP)||25V - 70V**.

Here are my very poor guesses. I'm hoping to use each amp as a monoblock to power a single speaker. I can bi-amp if I need to, but I usually just use single-ended speaker cables to the jumpered speaker posts.

1. My understanding is that HI & LO are biamping outputs. One output
would go to my speaker's positive treble post, and the other would go to
the positive bass post. I'm not sure where the corresponding negative
wires would connect.
2. My guess is that COM & + over the "AMP" category would be for
non-bi-wired, singled-ended output to a speaker's single positive and
negative posts? COM would be negative, and + would be positive?
3. My conclusion is that because I'm not using a PA's distributed
audio system with multiple speakers connected to the amp, I should use
the 25V maximum output voltage rather than the 75V output setting for my two speaker system. But which speaker wire would be connected to the 25V terminal?

I know there are lots of folks here who are sound engineers and who have worked with decades of pro audio equipment. I'll just express my confidence that many people will know what to do, and offer my thanks in advance of your replies. Thanks!