John wrote:
All:

I want to use an AC/DC voltage source to replace a device that only
takes 4 D-cell batteries. What would the equivalent DC power and
current ratings be for an AC/DC supply?

Thanks in advance!

John

1.5, 3.0, or 6.0 volts, nominal, depending on how the batteries are aligned
with each other.

Take the device to your supplier (Radio Shack?) and trust the male behind
the counter to deduce what you need.