Can a preamp's gain be lowered?

Bob, I completely agree with you, but Kevin at Upscale assured me that he's never had a problem mating an AE-3 DJH with amps that have less than 1v input sensitivity. My DAC has an output of 1.8v which is less than your average 2v. My speakers are 87 dB inefficient, so that may help tame the gain as well. I don't have the AE-3 in my possession, so this may be a moot exercise, but I'm preparing myself for the worse case scenario.

Thanks again.

My DAC seems to have too high an output - I've had preamp manufacturers lower the gain of an input for me. They were able to to -6db.

I built my own balanced attenuators for the input side of a tube preamp using Vishay resistors from Partsconnexion. I was able to try a few combinations first then zero in on the level of reduction that worked best. I also tried the Endlers, which were ok, but not as good as the ones I made. You could easily build them inside the preamp, and that way you would only have to reduce gain at one of the inputs. I would stick with the least amount of attenuation that works for you, since I believe that attenuation reduces dynamics.

I would second Mitch2 both on building own with the least attenuation that works and on reducing gain at individual inputs. The second point may be more important on older equipment where phono/tuner outputs are lower than on the digital source. Can make a big difference in "listenability".
If not here someone at the diyaudio.com will tell what value to use. It's pretty easy to diy and you can pick the parts. Good luck.