Marantz 6000 OSE direct to amp?

I've just bought a used Marantz 6000 OSE which has a variable output/volume control. I read a reviewers claim that the player improved dramatically when connected directly to his amp. I have a Classe Audio CAP-151 integrated amp in which the amp and preamp sections can be disconnected from each other so I connected the 6000 OSE directly to the amp portion. Incredibly enough the all around improvement in sound was amazing. My problem is that with the player's volume control turned all the way down the gain was still very high and in the late evening I need to be able to turn it down. Can anybody suggest a way to accomplish this.
TIA
DG
Fort Myers, Florida