compare 1970-2006 receivers in power amps

hello. I had a pioneer sx 1280 receiver. I have a sansui z 7500 receiver. I would think as time went on technolgy should be better. as cars have better gas milage better performance etc. I did own a denon avr 5700, when i got the unit home I was very disapointed with the sound quaility compare to the older pioneer or sansui receiver i had. So i pawn it:applaud: Some one please tell me why the older eq has so much more bass and treble and balls compare to the new stuff. I want to buy a new power amp that has deep bass and crisp highs. with out spending a arm and a leg. or do I have to buy a old 1970 era power amp to get the sound I am searching for.any input:blink: