Or you could just un hook the pre to amp.But does this unit have manufaturer suggesting burn in or (reliable) revier saying it needs it???If it's tube unit I certainly wouldn't waste the tubes doing it.Guess some pople invest in cable cookers and reverse RIAA boxe and so forth but I wouldn't just assume it needs it.At least I'd say don't wait to use it till it's been been used for 2000 hours like some neurotics do.
Chazz
Chazz