I know the early chuch didn't use musical instruments in worship because I've researched very early church history. I'm no expert in it, but it's not a terribly difficult thing to research if you are interested in it. There are English translations available of the writings of early 2nd century church members. There are also "outsider" accounts of Christianity from the 1st and 2nd centuries (Pliny, Josephus, Suetonius), as well as the New Testament accounts. Musical instruments just weren't used in worship. I have not seen any account of their use earlier than the 600s. If you know of earlier accounts, I would very interested in them.
As to wearing togas and riding camels, perhaps I didn't communicate well. I did not mean to imply that we do everything that 1st century Christians did. First century Christians did some things because they were 1st century (for example, wear togas) and other things because they were Christians (for example, worship God). We are trying to imitate the things which they did because they were Christians. We don't particularly care about imitating the things they did merely because they lived in the 1st century.
Again, I am NOT implying that there is anything sinful about musical instruments themselves. I don't know whether or not the Primitive Baptists think musical instruments are sinful. I know that the Old Regular Baptists, like the churches of Christ, sing a cappella in worship for the reasons stated in my posts above, NOT because of any objections to instrumental music in general.