Maybe so it's too late to return it?
Why does it take so many hours to brea in arc preamps and amps?
I recently purchased a like new ARC 5 SE pre amp. The unit had less than 200 hours on it. Everything I have read states that ARC preamps take up to 600 hours to fully break in. Why is this so and what improvements can I expect to hear as the unit accrues hours?