[geraldsmallbear]

I have an Audio-GD NFB-2 that needs it's output volume lowered. 
 
I had it raised by Kingwa a while ago and due to a new amp set-up I want to drop it back to the standard line-level output.
 
I'm not an electronics person so I'm asking for some help to get me started learning what I need to do and what precautions to take. 
 
I know where to find the schematics but mine was repaired by Kingwa and some of the internals have been changed. Perhaps the config is the same, just different parts?
 
I've been unable to get in touch with Kingwa. 
 
I'm using the USB input and going RCA out.