Does placing my Adsense publisher's account code over many website's will reduce earnings?
I mean by many websites, that sites are mine or I have exclusive rights to publish my ads there. Keep in mind that, some of those websites may has just 30 visits per day while others may exceed 1000 visits per day.
No. Google doesn't mind if you publish adv on one or more websites. However, on average you could see a decline in earnings adding more website as well as you could see a growth. The earnings are driven by what Google does and that is Google shows adv based on the content of your website and some info extracted by visitors. So, the money you can earn with a click really depends on those facts and not by the number of websites you publish adv.
