The CJ CAV-50 is the 40W per channel Ultralinear integrated.
To get it "up to par" with speakers worthy of diamond tweeters you need to sink in major $$$ to redo the power supply.
Do you want to stick with Integrated amp or go separate?
The only integrated amps I can think of that matches the class of 804D would be a VAC Phi or upgraded Avatar.
Otherwise a highly modified Jolida JD502 might work.
To get it "up to par" with speakers worthy of diamond tweeters you need to sink in major $$$ to redo the power supply.
Do you want to stick with Integrated amp or go separate?
The only integrated amps I can think of that matches the class of 804D would be a VAC Phi or upgraded Avatar.
Otherwise a highly modified Jolida JD502 might work.