Amp repair...What to expect.

I love the sound of my sunfire 300 and I'm using both current and voltage outputs to the different drivers.
The right channel blew out, so I sent it for repair and told them to also upgrade the electronics. Now, the amp sounds nothing like it did before service. Loss of detail, 3D image was huge and is gone.
Theduke answered my question somewhat, but how many hours is the typical burnin period?

should not take long. maybe a week full of listening or running some music at low volume levels.

Minimum of 200-300 hours. Maybe as long as 400-500 hours.

Thanks, Mofi. It's frustrating because it's not like burning in a new tube or a cable, which can be an adventure. In this case we know the sound of our system and now it's a waiting game to get back to that sound we know so well.

Yea maybe 2...3 years indeed or what?
Rule of thumb is if it sounds bad out of the box, the burn-in won't fix that.