It's like the'd' which is a voiced consonant, takes the feature the voicing feature of whatever comes before, so if it's a voiced consonant then it remains a voiced'd'.
It's unvo- it's voiced. And the voiced TH in an unstressed word can be made without the tongue tip coming through. 'Blame this', 'this', 'this', 'this'.
Now, I've made some videos about voiced and voiceless consonant sounds, so you can click on this link and it'll take you to those and show you the difference.