I pulled the fan and noted no difference in sound levels. Perhaps a little less efficient dust collection when hooked up to my Oneida mini-gorilla. I have recorded db levels in the 105 to 108 range when planing wood with the 735 - my family above me would cringe. Great planer that screams.
Also removing the impeller will save about 2 amps, less likely to trip the internal breaker.
I think it was Jim Toplin in one of his books said he gave up his stationary planer for a benchtop model which he kept in the rafters and lowered with pulleys when he needed it.
Hobbyist woodworker
Maryland
Unpopular opinion: The DeWalt 734 is just as good as the 735, but at a cheaper cost. The advantages of the 735 (build in eject fan) and two speeds aren't enough to justify the price different, IMHO. The 735's build in dust ejection fan is a nice feature, IF you don't own a dust collector already. Even if you don't, the HF $200 special is going to be a better option. The dual speeds are nice, but not really necessary. In this case the 734 also shaves about 20# off the weight.