Hi Wayne,
My apologies for the delay. I see from your schematic that you have copied the output structure from the eval board. There's nothing inherently wrong with doing this, but the resistor divider network on the AD8372 eval board was designed so that the eval board output would be matched to 50 ohm instruments, even though the AD8372 is seeing a differential output impedance of 250 ohms, which is optimal for performance. Long story short, but you are seeing exactly what I expect (and what I see when I use the eval board). Is this what you are looking for? Do you need to see 50 ohms in your system at this point? If not, you could scrap existing resistor output structure for something that looks like 250 ohms looking from the amp out, and also 250 ohms looking from the next stage back to the AD8372. Please let me know if there is anything else I can do to help you,
Steve