Help! Power question

PS. ... IF you are not familiar with electric wiring and experienced at handling it, an electrician is really the way you should go, with 1 word of caution.... if you are not familiar with the electricians reputation, ensure he checks everything, rather than just walk up to the panel and say you need a new one. ..   big job... big $... he likely wouldn't lie, but that doesn't mean it is the simplest solution to the problem you want fixed at this moment when securing connections might do the trick for $100 instead of a thousand.

The house may not have enough amperage available on the line entering the house to add a big air conditioner to the existing line?Particularly old houses just never had the idea of 100 amps being used..A response from a Googled question about lights dimming (which is similar)"" Start by checking your voltage as close to the source as possible (like at the meter base) when the A/C or heat cuts on. If you have an excessive voltage drop here, you may need to get your utility involved to check supply voltage, transformer loading, supply connections, service wire size. If the problem is beyond the meter, check your voltage drops moving towards the lights and A/C until you find the problem (small wire size or bad connections are most likely). ""

PPS...  I mistook your "surge protector" for "power conditioner"... that in mind, a surge protector only protects your equipment for HI power spikes by cutting them off....it can not effect low power dips.

TY all, very informative   ps: the new air is a 2.5 ton unit and "modern" the old unit was 25+ years old 3 ton and did not cause this problem
interesting
thanks again

That is interesting now that I understand it was a replacement and not a first time install. Hmmm ... it has to be the new unit simply has a much higher initial current draw to get going than the old one did.  Yet, everything we all stated still applies, except my comment that they may have used your breaker position from the audio line, since the positions from the old ac units breakers would be available.