I am not an hifi expert but I noted it to. Placed aftermarket insulators between floor and the case of left channel power amp, no insulators on right channel amp just its own feet, I played a cd with mono button on, balancing left to right and viceversa I could definitely hear better bass frequencies, tight and clean. After switching insulators to right channel amp there was still the same improvement, so I was sure it was not my room and furniture that influenced the difference.