Mcintosh C39 and a MC7106 Bass / Treble Problem


Hi,
I am running a Mcintosh C39 and a MC7106 to 6 Vienna Acoustics Waltz Speakers. When I try to adjust the bass or the treble the dial does not seem to have any effect on the actual audio and the sound is coming just flat. Any ideas, am I missing something?
Thanks for the help!
cchiara1