Perhaps the simplest solution would be an integrated that has the inputs that allow one to bypass the preamp and use the integrated solely as an amplifier (what's the term for this input?). What feature would I be looking for and could I get some recommendations up to $1500 used?The most common term is HT Bypass.
Here is a link to a comprehensive list of integrateds having this feature. As your looking to buy used you should be able to find one that addresses your needs with your budget.
http://www.audiophile.no/en/articles-tests-reviews/item/426-amplifiers-with-processor-input