@california smith not exactly sure about your question, but you may want search the forum "conversion to euros". I have not tried. but I think you may experience some difficulty in actually trying to pay or exchange dollars. In general, I use my ATM card and get out enough euros for several days at a time. Especially if I am going to be in smaller towns. I use my credit card where I can. I have my bank do the conversion for me and always pay in euros. I never ever ask to pay in dollars ... it is an opportunity for some entity to make a buck. My credit card does not have foreign transaction fees, and my ATM fees are reimbursed.
Exchanging currency is often a long involved process, the banks may be closed just when you need them the most, and greenbacks will need a money belt, an emergency stash in your backpack, and some in your wallet for the day by day necessities. Credit cards make life much easier but if you go that way take two - never know when you will forget it in a shop, leave it on the bar, or forget it somewhere else.