Suggestions for pure headphone amp around $200?

I am looking for suggestions for a new to me headphone amp with a budget around $200, maybe a little more for the right unit.
I do NOT need a headphone/dac, it will be fed by RCA analog from the line out of my BAT integrated.
One requirement is that it also has RCA analog outputs, so a pass through if you like, my present el cheapo Monolith head amp has this and it is near essential in my set up right now.
My present cans are HiFiman 4xx purchased from Drop.
I may be looking at better cans for Xmas so there is that to bear in mind for the new head amp.
Thanks and stay safe!