Good point. I connected the Tape Out of the HK 3490 to the Aux input of a Bose Lifestyle 8 home theater speaker system. That I am aware of, this has no gain control. But the volume control seemed to work acceptably. What are the chances that the attenuation of the HK 3490 Tape Out is set just right to function as an Aux input to the Bose system?
By the way, why isn't there a standard that fixes the attenuation of all outputs at the same level (so that there is no need for gain control)?