We've already been listening to the amp. FWIW the squarewave response you linked does look pretty bad. Our tube amps can do better than that!
Obviously we're not letting this thing out without it doing what its supposed to do.
The thing is, you can have all sorts of issues when building a switching amplifier. The layout of the boards is critical- if not done right you can get stability problems. The little 'dimples' in the squarewaves you linked say to me that there is a suppressed oscillation in the amp somewhere. The squarewave should have been flat across the top, but its not! That's not a switching frequency thing as it is a stability thing.
Obviously we're not letting this thing out without it doing what its supposed to do.
The thing is, you can have all sorts of issues when building a switching amplifier. The layout of the boards is critical- if not done right you can get stability problems. The little 'dimples' in the squarewaves you linked say to me that there is a suppressed oscillation in the amp somewhere. The squarewave should have been flat across the top, but its not! That's not a switching frequency thing as it is a stability thing.