I'm running a VP150 with an HK 635 and have never had any of the issues you are describing, nor have I ever felt the need to tweak the tone controls on the 635. I also believe there are a few of us with AVR635s around these parts and I don't recall ever reading problems such as yours on the board. To me it doesn't sound like a power problem ... I presume everything is connected correctly and properly calibrated? Have you nailed the problem to the 150 center and if so, have you checked the drivers in the speaker to make sure they are working like they should be? Also, do you have this issue whenever you are in 2 channel stereo mode?

If you want to check if it's a problem with the receiver you can connect one of your 60's as your center.

Rick
Our Room

smile