I've had a Trek 2000 since about 2005 and recently replaced the FD, RD, cassette, chain, brake/shift levers, and all the cable/housing. All new 5700 series 105 parts, except for the chain which is Ultegra. Years ago I replaced the triple 105 crank that came with the bike with an FSA Team Carbon double 53/39. My old cassette was 9spd and the new is 10spd.

With the new setup I get a grinding noise when pedaling under load in my small chainring. Not an ear-splitter, but definitely sounds wrong. Shift up to the 53 and the noise is gone. The 39t doesn't appear to be worn out, and wasn't making the noise before swapping out all the above parts. The sound isn't the chain rubbing on the FD cage. Chain is lubed, everything is new and clean, I'm sure I sized the chain correctly, and I've put about 50 miles on the setup to see if maybe the chain just needed to get to know the chainring but it still sounds the same.

What should I check? Is there anything else with chain alignment that I might've missed? Thanks!