In English, Ds are almost always pronounced the same. A D at the end of a word is usually pronounced the same as a D in the middle or at the beginning of a word. For example, the D in “feed” is the same as the D in “feeding” or “feeds.” The D in “head” is pronounced the same as in “heading.” Both Ds in “headed” are pronounced the same. Both Ds in “did” are pronounced the same. The D in “dog” is the same as the D in “food.”
These words all sound different:
An exception to this is for some verbs in the past tense, ending in ed, the D sounds like a T. For example diced, tasked, wiped, and watched.
In English, D is a voiced sound:
Voiced and Unvoiced Sounds