The HDMI is a digital signal and the CRT is an analog display device, so your Sony must do some Digital-to-Analog conversions that might be creating the artifacts. Try using the component connections, which are analog, from the Denon to the Sony to see if there is any improvement.
With many analog (CRT) and less-than-perfect digital display devices (LCD, DLP, Plasma, etc.), the analog component connection will look "smoother" and have fewer artifacts than the digital connection (DVI, HDMI). Of course, using component will sacrifice some resolution, but life is full of compromises. Try both and see what looks best to you.